Att G.19_Ventilator-Associated Event

Att G.19_Ventilator Associated Event.pdf

The National Healthcare Safety Network (NHSN)

Att G.19_Ventilator-Associated Event

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Device-associated Module
VAE

Ventilator-Associated Event (VAE)
For use in adult locations only
Table of Contents:
Introduction
Settings
Requirements
Definitions
Reporting Instructions
Figures 1-4, VAE Algorithm
Numerator Data
Denominator Data
Data Analyses
References
Appendix of Antimicrobial Agents
Frequently-Asked Questions

1
3
3
3
16
18
23
23
23
25
27
29

Introduction: Mechanical ventilation is an essential, life-saving therapy for patients with
critical illness and respiratory failure. Studies have estimated that more than 300,000 patients
receive mechanical ventilation in the United States each year [1-3]. These patients are at high
risk for complications and poor outcomes, including death [1-5]. Ventilator-associated
pneumonia (VAP), sepsis, Acute Respiratory Distress Syndrome (ARDS), pulmonary embolism,
barotrauma, and pulmonary edema are among the complications that can occur in patients
receiving mechanical ventilation; such complications can lead to longer duration of mechanical
ventilation, longer stays in the ICU and hospital, increased healthcare costs, and increased risk of
disability and death. Mortality in patients with acute lung injury on mechanical ventilation has
been estimated to range from 24% in persons 15-19 years of age to 60% for patients 85 years and
older [4].
Surveillance for ventilator-associated events in the National Healthcare Safety Network (NHSN)
prior to 2013 was limited to VAP. For the year 2012, VAP incidence for various types of
hospital units ranged from 0.0-4.4 per 1,000 ventilator days [6]. However, there is currently no
valid, reliable definition for VAP, and even the most widely-used VAP criteria and definitions
are neither sensitive nor specific [7-10].
A particular difficulty with many commonly-used VAP definitions, including the NHSN PNEU
definitions (revised in 2002), is that they require radiographic findings of pneumonia. Evidence
suggests that chest radiograph findings do not accurately identify VAP. The subjectivity and

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variability inherent in chest radiograph technique, interpretation, and reporting make chest
imaging ill-suited for inclusion in a definition algorithm to be used for the potential purposes of
public reporting, inter-facility comparisons, and pay-for-reporting and pay-for-performance
programs. Another major difficulty with available VAP definitions is their reliance on specific
clinical signs or symptoms, which are subjective and may be poorly or inconsistently
documented in the medical record. The NHSN PNEU protocol includes multiple definition
pathways and special criteria for selected patient populations (e.g., children,
immunocompromised patients), increasing its complexity.
The limitations of VAP surveillance definitions have implications for prevention. Valid and
reliable surveillance data are necessary for assessing the effectiveness of prevention strategies. It
is notable that some of the most effective measures for improving outcomes of patients on
mechanical ventilation do not specifically target pneumonia prevention [11-14].
In 2011 CDC convened a Working Group composed of members of several stakeholder
organizations to address the limitations of the NHSN PNEU definitions and propose a new
approach to surveillance for Ventilator-Associated Events (VAE) for NHSN [15]. The
organizations represented in the Working Group include: the Critical Care Societies
Collaborative (the American Association of Critical-Care Nurses, the American College of Chest
Physicians, the American Thoracic Society, and the Society for Critical Care Medicine); the
American Association for Respiratory Care; the Association of Professionals in Infection Control
and Epidemiology; the Council of State and Territorial Epidemiologists; the Healthcare Infection
Control Practices Advisory Committee’s Surveillance Working Group; the Infectious Diseases
Society of America; and the Society for Healthcare Epidemiology of America.
The VAE surveillance definition algorithm developed by the Working Group and implemented
in the NHSN in January 2013 is based on objective, streamlined, and potentially automatable
criteria that identify a broad range of conditions and complications occurring in mechanicallyventilated adult patients [16]. Several modifications to the VAE definitions have been made
since January 2013. These modifications address issues raised by NHSN users and discussed
with the Working Group. There are three definition tiers within the VAE algorithm: 1)
Ventilator-Associated Condition (VAC); 2) Infection-related Ventilator-Associated
Complication (IVAC); and 3) Possible VAP (PVAP). Data indicate that streamlined, objective
algorithms to detect ventilator-associated complications (similar to the VAC tier of the VAE
algorithm) are easily implemented, can make use of electronic health record systems to automate
event detection, and identify events that are clinically important and associated with outcomes
such as ICU and hospital length of stay and mortality [16,17]. Research suggests that most VACs
are due to pneumonia, ARDS, atelectasis, and pulmonary edema [16]. These are significant
clinical conditions that may be preventable.
NOTE: The VAE definition algorithm is for use in surveillance; it is not a clinical definition
algorithm and is not intended for use in the clinical management of patients. Examples provided

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throughout this protocol and in the VAE “Frequently-Asked Questions” are for illustration
purposes only and are not intended to represent actual clinical scenarios.
Settings: Inpatient locations eligible to participate in VAE surveillance are those adult locations
in acute care hospitals, long term acute care hospitals, and inpatient rehabilitation facilities where
denominator data (ventilator and patient days) can be collected for patients. Such locations may
include critical/intensive care units (ICU), specialty care areas (SCA), step-down units, wards,
and long term care units. A complete listing of adult inpatient locations can be found in Chapter
15.
NOTE: It is not required to monitor for VAEs after discharge if a patient is transferred to another
facility while still on mechanical ventilation. However, VAEs discovered within 2 calendar days
of discharge (where the day of discharge is day 1) should be reported to NHSN. No additional
ventilator days are reported.
Requirements: Surveillance for VAE in at least one inpatient location in the healthcare
institution for at least one calendar month as indicated in the Patient Safety Monthly Reporting
Plan (CDC 57.106). The VAE algorithm is only applicable to mechanically-ventilated patients in
adult locations.
Definitions:
VAE: VAEs are identified by using a combination of objective criteria: deterioration in
respiratory status after a period of stability or improvement on the ventilator, evidence of
infection or inflammation, and laboratory evidence of respiratory infection. The following pages
outline the criteria that must be used for meeting the VAE surveillance definitions (Figures 1-4).
To report VAEs, use the Ventilator-Associated Event form (CDC 57.112 ) and Instructions for
Completion.
NOTE: Patients must be mechanically ventilated for more than 2 calendar days to be
eligible for VAE. The earliest day on which VAE criteria can be fulfilled is day 4 of
mechanical ventilation (where the day of intubation and initiation of mechanical
ventilation is day 1). The earliest date of event for VAE (the date of onset of worsening
oxygenation) is day 3 of mechanical ventilation. Line lists of VAE data elements
demonstrating scenarios that meet and do not meet the VAE definitions are presented in
“Frequently-Asked Questions (FAQs)” number (no.) 2 at the end of this chapter.
NOTE: The baseline period of stability or improvement on the ventilator is defined as the
2 calendar days immediately preceding the first day of increased daily minimum PEEP or
FiO2, and must be characterized by ≥ 2 calendar days of stable or decreasing daily
minimum FiO2 or PEEP values (i.e., the daily minimum PEEP or FiO2 on the second day
of the baseline period of stability or improvement must be equal to or less than the daily
minimum PEEP or FiO2 on the first day of the baseline period of stability or

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improvement). The definitions of “daily minimum PEEP” and “daily minimum FiO2” are
included below. Note that the minimum daily PEEP or FiO2 used for VAE surveillance is
the lowest setting during a calendar day that was maintained for at least 1 hour.
For the purposes of VAE surveillance, PEEP values between 0 cmH2O and 5 cmH2O will
be considered equivalent. This means that patients with daily minimum PEEP values
from 0 to 5 cmH2O must then have an increase in the daily minimum PEEP to at least 8
cmH2O, sustained for at least 2 calendar days, to meet the VAC definition.
EXAMPLE: In the example below, the baseline period is defined by mechanical
ventilation (MV) days 1 through 4 (shaded in light gray), and the period of worsening
oxygenation by MV days 5 and 6 (shaded in darker gray), where the daily minimum
PEEP is ≥ 3 cmH2O greater than the daily minimum PEEP during the baseline period.
Note that there is no VAC on MV day 3, because PEEP values 0-5 cmH2O are considered
equivalent for the purposes of this surveillance.
MV Day
1
2
3
4
5
6

Daily minimum
PEEP (cmH2O)
0
0
5
5
8
8

Daily minimum
FiO2 (oxygen concentration, %)
1.00 (100%)
0.50 (50%)
0.50 (50%)
0.50 (50%)
0.50 (50%)
0.50 (50%)

VAE

VAC

EXAMPLE: In the example below, the baseline period is defined by mechanical
ventilation (MV) days 1 through 4 (shaded in light gray), and the period of worsening
oxygenation by MV days 5 and 6 (shaded in darker gray), where the daily minimum
PEEP is ≥ 3 cmH2O greater than the daily minimum PEEP during the baseline period. In
this example, note that MV days 1-4 are considered a baseline period even though the
daily minimum PEEP increases from 0 to 3 to 5 cmH2O during this time period—because
PEEP values from 0-5 cmH2O are considered equivalent for the purposes of this
surveillance.
MV Day
1
2
3
4
5
6

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Daily minimum
PEEP (cmH2O)
0
0
3
5
8
8

Daily minimum
FiO2 (oxygen concentration, %)
1.00 (100%)
0.50 (50%)
0.50 (50%)
0.50 (50%)
0.50 (50%)
0.50 (50%)

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VAC

Device-associated Module
VAE

EXAMPLE: In the example below, the baseline period is defined by mechanical
ventilation (MV) days 3 and 4 (shaded in light gray), and the period of worsening
oxygenation by MV days 5 and 6 (shaded in darker gray), where the daily minimum FiO2
is ≥ 0.20 (20 points) over the daily minimum FiO2 during the baseline period.

MV Day
1
2
3
4
5
6

Daily minimum
PEEP (cmH2O)
8
6
5
5
6
6

Daily minimum
FiO2 (oxygen concentration, %)
1.00 (100%)
0.50 (50%)
0.40 (40%)
0.40 (40%)
0.70 (70%)
0.70 (70%)

VAE

VAC

EXAMPLE: In the example below, there is no VAC, because the FiO2 on MV day 4 is
higher than the FiO2 on MV day 3 (and therefore not stable or decreasing) – even though
the FiO2 on MV days 3 and 4 meets the 20-point threshold when compared with the daily
minimum FiO2 on MV days 5 and 6.
MV Day
1
2
3
4
5
6

Daily minimum
PEEP (cmH2O)
8
6
5
5
6
6

Daily minimum
FiO2 (oxygen concentration, %)
1.0 (100%)
0.50 (50%)
0.35 (35%)
0.40 (40%)
0.70 (70%)
0.70 (70%)

VAE

No event

NOTE: Patients on high frequency ventilation or extracorporeal life support are
EXCLUDED from VAE surveillance.
NOTE: Patients who are receiving a conventional mode of mechanical ventilation while
in the prone position and patients who are receiving a conventional mode of mechanical
ventilation while receiving nitric oxide therapy, helium-oxygen mixtures (heliox) or
epoprostenol therapy are INCLUDED in VAE surveillance.
NOTE: Patients on Airway Pressure Release Ventilation (APRV) or related modes (see
FAQ nos. 22 and 23), are INCLUDED, but the VAE period of stability or improvement
on the ventilator and the period of worsening oxygenation should be determined by
changes in FiO2 only, since changes in PEEP as indicated in this surveillance algorithm

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may not be applicable to APRV. In addition, patients with VAE who are on APRV or
related modes of mechanical ventilation should be indicated as such on the VAE Form
(CDC 57.112).
NOTE: VAEs are defined by a 14-day period, starting on the day of onset of worsening
oxygenation (the event date, day 1). A new VAE cannot be identified or reported until
this 14-day period has elapsed. See FAQ no. 4.
Date of event: The date of onset of worsening oxygenation. This is defined as the first calendar
day in which the daily minimum PEEP or FiO2 increases above the thresholds outlined in the
VAE definition algorithm (i.e., day 1 of the required ≥ 2-day period of worsening oxygenation
following a ≥ 2-day period of stability or improvement on the ventilator).
EXAMPLE: A patient is intubated in the Emergency Room for severe communityacquired pneumonia and admitted to the MICU (day 1). The patient stabilizes and
improves on days 2-5, with a daily minimum FiO2 of 0.35 (35%) on days 4 and 5. On day
6, the patient experiences respiratory deterioration, and requires a minimum FiO2 of 0.60
(60%) on days 6 and 7, meeting the criteria for a VAC. The date of the VAC event is day
6.
NOTE: The “date of event” is NOT the date on which all VAE criteria have been met. It
is the first day (of a ≥ 2-day period) on which either of the worsening oxygenation
thresholds (for PEEP or FiO2) is met.
VAE Window Period: This is the period of days around the event date (i.e., the day of onset of
worsening oxygenation) within which other VAE criteria must be met. It is usually a 5-day
period and includes the 2 days before, the day of, and the 2 days after the VAE event date (i.e.,
the first day of worsening oxygenation, the day of VAE onset). There is an exception, however,
in which the VAE Window Period is only 3 or 4 days, as follows:
In cases where the VAE event date corresponds to MV day 3 or day 4, the window period
described above may only be a 3-day or a 4-day window, because it can NOT include any
days before the 3rd day of MV. For example, if the VAE event date is MV day 3, then the
window period includes only the day of VAE onset and the 2 days after VAE onset
(because the 2 days before VAE onset are before the 3rd day of MV).
Positive End-Expiratory Pressure (PEEP): “A technique used in respiratory therapy in which
airway pressure greater than atmospheric pressure is achieved at the end of exhalation by the
introduction of a mechanical impedance to exhalation” [18]. In patients on mechanical
ventilation, PEEP is one of the key parameters that can be adjusted depending on the patient’s
oxygenation needs, and is typically in the range of 0 to 15 cmH2O. A sustained increase (defined
later in this protocol) in the daily minimum PEEP of ≥ 3 cmH2O following a period of stability
or improvement on the ventilator is one of two criteria that can be used in meeting the VAC

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definition. For the purposes of this surveillance, PEEP values from 0 to 5 cmH2O are considered
equivalent.
Fraction of inspired oxygen (FiO2): The fraction of oxygen in inspired gas. For example, the
FiO2 of ambient air is 0.21; the oxygen concentration of ambient air is 21%. In patients on
mechanical ventilation, the FiO2 is one of the key parameters that can be adjusted depending on
the patient’s oxygenation needs, and is typically in the range of 0.30 (oxygen concentration of
30%) to 1.0 (oxygen concentration of 100%). A sustained increase (defined later in this protocol)
in the daily minimum FiO2 of ≥ 0.20 (20%) following a period of stability or improvement on the
ventilator is the second of the two criteria that can be used in meeting the VAC definition.
Daily minimum PEEP: The lowest value of PEEP during a calendar day that is set on the
ventilator and maintained for at least 1 hour. This requirement that the daily minimum PEEP be
the lowest setting maintained for at least 1 hour will ensure that units monitoring and recording
PEEP settings hourly or more frequently than once per hour are able to apply the VAE
surveillance PEEP criterion in a standardized way. In the event that ventilator settings are
monitored and recorded less frequently than once per hour, the daily minimum PEEP is simply
the lowest value of PEEP set on the ventilator during the calendar day. In circumstances where
there is no value that is documented to have beenmaintained for at least one hour (e.g., the lowest
value of PEEP is set late in the calendar day, mechanical ventilation is discontinued early in the
calendar day, PEEP settings are changed very frequently throughout the calendar day) the daily
minimum PEEP should default to thelowest PEEP setting during the calendar day (regardless of
how long that setting was maintained). For example, a patient who is intubated and started on
mechanical ventilation at 11:30 pm on June 1, with a PEEP setting of 10 cmH2O from 11:30 pm
to midnight, would have a daily minimum PEEP of 10 cmH2O on June 1 for the purposes of
VAE surveillance
NOTE: In units tracking PEEP settings every hour or more frequently than every hour,
there must be sufficient consecutive recordings of a specific PEEP setting to meet the
minimum required duration of 1 hour. For example, in units tracking PEEP every 15
minutes, 5 consecutive recordings of PEEP at a certain level would be needed to meet the
required 1 hour minimum duration (e.g., at 09:00, 09:15, 09:30, 09:45 and 10:00). In
units tracking PEEP every 30 minutes, 3 consecutive recordings of PEEP at a certain
level would be needed to meet the required 1 hour minimum duration (e.g., at 09:00,
09:30, and 10:00). In units tracking PEEP every hour, 2 consecutive recordings of PEEP
at a certain level would be needed to meet the required 1 hour minimum duration (e.g., at
09:00 and 10:00).

EXAMPLE: The patient is intubated at 6 pm. PEEP is set at the following values through
the remainder of the calendar day:
Time
6 pm
7 pm
8 pm
9 pm
10 pm
11 pm
10
8
5
5
8
8
PEEP
(cmH2O)

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In this example, the daily minimum PEEP for the purposes of VAE surveillance is 5
cmH2O. PEEP settings are being monitored and recorded every hour. There are two
consecutive hours where the PEEP setting is noted to be 5 cmH2O (8 pm and 9 pm), and
therefore required minimum duration of 1 hour is met.
EXAMPLE: The patient is intubated at 6 pm. PEEP is set at the following values through
the remainder of the calendar day:
Time
PEEP
(cmH2O)

6 pm
8

7 pm
8

8 pm
5

9 pm
8

10 pm
5

11 pm
8

In this example, the daily minimum PEEP for the purposes of VAE surveillance is 8
cmH2O. PEEP settings are being monitored and recorded every hour. Although the
lowest PEEP is 5 cmH2O, it is recorded at two non-consecutive time points only (8 pm,
then 10 pm), and so the required 1 hour minimum duration is not met. There are two
consecutive hours where the PEEP setting is noted to be 8 cmH2O (6 pm and 7 pm), and
therefore the required minimum duration of 1 hour is met to allow use of this setting as
the daily minimum value for VAE surveillance.

EXAMPLE: PEEP is set at the following values through the course of a calendar day:
Time
PEEP
(cmH2O)

12 am
5

4 am
8

8 am
5

12 pm
8

4 pm
8

8 pm
10

In this example, the daily minimum PEEP is 5 cmH2O. PEEP settings are being
monitored and recorded every 4 hours; therefore the lowest recorded PEEP setting for the
calendar day is the value used in VAE surveillance.
EXAMPLE: You are reviewing a patient’s ventilator settings on Wednesday morning to
determine the daily minimum PEEP values for Monday and Tuesday. The MICU
monitors and records PEEP settings for mechanically ventilated patients every 30
minutes. You see that the lowest PEEP setting on Monday (5 cmH2O) was recorded at
11:30 pm when the episode of mechanical ventilation was initiated for this patient. Te
patient remained at this PEEP setting for an additional 30 minutes on Tuesday morning,
and was then maintained on PEEP 10 cmH2O for the rest of the day on Tuesday. What do
you record as the daily minimum PEEP for Monday and for Tuesday? In this example,
the only PEEP setting recorded on Monday was 5 cmH2O. Because there is no value on
Monday that has been maintained for at least one hour, the lowest (and only) setting of 5

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cmH20 is recorded as the daily minimum PEEP for that calendar day.On Tuesday, the
daily minimum PEEP should be recorded as 10 cmH2O, which is the lowest PEEP setting
maintained for at least 1 hour on Tuesday.
Day
Monday
Tuesday
Tuesday
Tuesday
Tuesday
Tuesday

Time
23:30
00:00
00:30
01:00
01:30
02:00 through 23:30

PEEP (cmH2O)
5
5
5
10
10
10

Daily minimum FiO2: The lowest value of FiO2 during a calendar day that is set on the ventilator
and maintained for at least 1 hour. This requirement that the daily minimum FiO2 be the lowest
setting maintained for at least 1 hour will ensure that units monitoring and recording FiO2
settings hourly or more frequently than once per hour are able to apply the VAE surveillance
FiO2 criterion in a standardized way. In the event that ventilator settings are monitored and
recorded less frequently than once per hour, the daily minimum FiO2 is simply the lowest value
of FiO2 set on the ventilator during the calendar day. Similarly, in circumstances where there is
no value that has been maintained for at least one hour (e.g., the lowest value of FiO2 is set late
in the calendar day, mechanical ventilation is discontinued early in the calendar day) the daily
minimum FiO2 is the lowest value of FiO2 set on the ventilator during the calendar day.
NOTE: In units tracking FiO2 settings every hour or more frequently than every hour,
there must be sufficient consecutive recordings of a specific FiO2 setting to meet the
minimum required duration of 1 hour. For example, in units tracking FiO2 every 15
minutes, 5 consecutive recordings of FiO2 at a certain level would be needed to meet the
required 1 hour minimum duration (e.g., 09:00, 09:15, 09:30, 09:45 and 10:00). In units
tracking FiO2 every 30 minutes, 3 consecutive recordings of FiO2 at a certain level would
be needed to meet the required 1 hour minimum duration (e.g., 09:00, 09:30, and 10:00).
In units tracking FiO2 every hour, 2 consecutive recordings of FiO2 at a certain level
would be needed to meet the required 1 hour minimum duration (e.g., 09:00 and 10:00).

EXAMPLE: The patient is intubated at 6 pm. FiO2 is set at the following values through
the remainder of the calendar day:
Time
FiO2

6 pm
1.0

7 pm
0.8

8 pm
0.5

9 pm
0.5

10 pm
0.8

11 pm
0.8

In this example, the daily minimum FiO2 for the purposes of VAE surveillance is 0.5.
FiO2 settings are being monitored and recorded every hour. There are two consecutive
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hours where the FiO2 setting is noted to be 0.5 (8 pm and 9 pm), and therefore required
minimum duration of 1 hour is met.

EXAMPLE: The patient is intubated at 6 pm. FiO2 is set at the following values through
the remainder of the calendar day:
Time
FiO2

6 pm
0.8

7 pm
0.8

8 pm
0.5

9 pm
0.8

10 pm
0.5

11 pm
0.8

In this example, the daily minimum FiO2 for the purposes of VAE surveillance is 0.8.
FiO2 settings are being monitored and recorded every hour. Although the lowest FiO2 is
0.5, it is recorded at two non-consecutive time points only (8 pm, and then 10 pm), and so
the required 1 hour minimum duration is not met. There are two consecutive hours where
the FiO2 setting is noted to be 0.8 (6 pm and 7 pm), and therefore the required minimum
duration of 1 hour is met to allow use of this setting as the daily minimum value for VAE
surveillance.

EXAMPLE: FiO2 is set at the following values through the course of a calendar day:
Time
FiO2

2 pm
1.0

4 pm
0.60

6 pm
0.40

8 pm
0.50

10 pm
0.55

12 am
0.60

In this example, the patient was intubated at 2 pm. The daily minimum FiO2 is 0.40. FiO2
settings are being monitored and recorded every 2 hours; therefore, the lowest recorded
FiO2 setting for the calendar day is the value used in VAE surveillance.
EXAMPLE: You are reviewing a patient’s ventilator settings on Friday morning to
determine the daily minimum FiO2 value for Thursday, the day of mechanical ventilation
initiation. The ICU monitors and records FiO2 settings for mechanically ventilated
patients every 15 minutes. Based on the information recorded in the table below, what
should you record as the daily minimum FiO2 for Thursday? In this example, since there
is no setting that is maintained for at least 1 hour during the calendar day, the daily
minimum FiO2 for Thursday is 0.50 (50%). This is the lowest value of FiO2 set on the
ventilator during the calendar day.
Day
Thursday

January 2015

Time
09:00
09:15
09:30
09:45

FiO2
0.80
0.60
0.60
0.50

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Day

Time
10:00
10:15
10:30
10:45
11:00
11:15
11:30
11:45
12:00 to 23:45

FiO2
0.50
0.50
0.50
0.55
0.55
0.55
0.55
0.60
0.60

Ventilator: A device to assist or control respiration, inclusive of the weaning period, through a
tracheostomy or by endotracheal intubation.
NOTE: Lung expansion devices such as intermittent positive-pressure breathing (IPPB);
nasal positive end-expiratory pressure (nasal PEEP); and continuous nasal positive
airway pressure (CPAP, hypoCPAP) are not considered ventilators unless delivered via
tracheostomy or endotracheal intubation (e.g., ET-CPAP).
Episode of mechanical ventilation: Defined as a period of days during which the patient was
mechanically ventilated for some portion of each consecutive day.
NOTE: A break in mechanical ventilation of at least one full calendar day, followed by
reintubation and/or reinitiation of mechanical ventilation during the same hospitalization,
defines a new episode of mechanical ventilation.
EXAMPLE: A patient is intubated and mechanical ventilation is initiated at 11 pm on
hospital day 1. The patient remains intubated and mechanically ventilated from hospital
days 2-10. The patient is extubated at 9 am on hospital day 11, and remains extubated on
hospital day 12. The patient is reintubated and mechanical ventilation is reinitiated on
hospital day 13. The patient remains intubated and mechanically ventilated from hospital
day 14-18. This patient has had two episodes of mechanical ventilation (days 1-11 and
days 13-18), separated by at least one full calendar day off of mechanical ventilation.
New antimicrobial agent: Defined as any agent listed in the Appendix that is initiated on or after
the third calendar day of mechanical ventilation AND in the VAE Window Period (i.e., the
period typically defined by the 2 calendar days before, the day of, and the 2 calendar days after
the onset date of the VAE). The agent is considered new for the purposes of this definition if it
was NOT given to the patient on either of the 2 days preceding the current start date.
EXAMPLE: A patient is intubated and mechanically ventilated on hospital day 1 in the
MSICU. Ceftriaxone and azithromycin are started on day 1 and administered daily. After
3 days of improving respiratory status, the patient’s oxygenation deteriorates on days 4

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and 5, with a daily minimum PEEP that is 4 cmH2O higher than it was on days 2 and 3.
Criteria for the VAC definition are met; the date of the event is hospital day 4.
Ceftriaxone is discontinued and meropenem is begun on day 5. Azithromycin is
continued. In this case, meropenem is a new antimicrobial agent: 1) it was begun on day
5 of mechanical ventilation, and 2) within the VAE Window Period (on the day after
VAE onset), and 3) it was not given to the patient on either of the 2 days preceding the
current start date. By contrast, ceftriaxone and azithromycin would not be considered new
antimicrobial agents, since they were begun on day 1 of mechanical ventilation and
continued daily into the VAE Window Period.
The antimicrobial agent(s) must have been given by one of the routes of administration outlined
in Table 1, and therapy with one or more new antimicrobial agents must be continued for at least
4 calendar days (referred to as 4 “qualifying antimicrobial days” or “QADs”). For further
guidance on identification of new antimicrobial agents and on how to determine whether the
requirement for 4 QADs is met, refer to FAQs nos. 6-10 at the end of this chapter.

Table 1. Definitions of routes of administration
Route of Administrationa
Intravenous
Intramuscular
Digestive Tract
Respiratory Tract

Definitionb
An intravascular route that begins with a vein.
A route that begins within a muscle.
A route that begins anywhere in the digestive tract extending
from the mouth through rectum.
A route that begins within the respiratory tract, including the
oropharynx and nasopharynx.

Other routes of administration are excluded (e.g., antibiotic locks, intraperitoneal, intraventricular, irrigation, topical).
Definitions per SNOMED Reference Terminology

Qualifying Antimicrobial Day (QAD): A day on which the patient was administered an
antimicrobial agent that was determined to be “new” within the VAE Window Period. Four
consecutive QADs are needed to meet the IVAC antimicrobial criterion—starting within the
VAE Window Period. Days on which a new antimicrobial agent is administered count as QADs.
Days between administrations of a new antimicrobial agent also count as QADs as long as there
is a gap of no more than 1 calendar day between administrations. For example, if levofloxacin is
given on VAE Day 1, has not been given in the 2 preceding calendar days, and is given again on
VAE Days 3, 5 and 7, there are 7 QADs—because the days between levofloxacin doses also
count as QADs. By contrast, days between administrations of different antimicrobial agents do
NOT count as QADs; for example, if levofloxacin is given to the patient on VAE Days -2 and -1
only, no antimicrobials are given on VAE Day 1, and meropenem is given only on VAE Day 2
(remember there is no VAE Day 0), then there are not 4 consecutive QADs. VAE Days -2 and -1
count as 2 consecutive QADs, but VAE Day 1 cannot be counted as a QAD because it is a day
between different antimicrobial agents.

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Purulent Respiratory Secretions: Defined as secretions from the lungs, bronchi, or trachea that
contain >25 neutrophils and <10 squamous epithelial cells per low power field [lpf, x100].
NOTE: Some clinical laboratories may use different results reporting formats for direct
examinations of respiratory secretions. Additional instructions for using the purulent
respiratory secretions criterion are provided in Table 2, below.

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Table 2. Instructions for using the purulent respiratory secretions criterion, based on
laboratory reporting of respiratory secretion direct examination results.
How do I use the purulent respiratory
secretions criterion if …
My laboratory reports counts of “white blood
cells” or “polymorphonuclear leukocytes” or
“leukocytes” rather than counts of
“neutrophils”?
My laboratory reports semi-quantitative
results (not quantitative results) for numbers
of neutrophils and squamous epithelial cells?
My laboratory cannot provide additional
information on how its semi-quantitative
reporting corresponds to quantitative
reporting ranges for neutrophils and
squamous epithelial cells?
My laboratory reports only the numbers of
neutrophils present, without reporting the
number of squamous epithelial cells?

My laboratory uses different reporting
thresholds for neutrophils and squamous
epithelial cells (e.g., maximum report of ≥ 20
neutrophils per low power field [x100], or
minimum report of ≤ 15 squamous epithelial
cells per low power field [x100])?
My laboratory processes respiratory
specimens such as bronchoalveolar lavage
fluid using a centrifugation procedure (e.g.,
“cytospin”), and there is no quantitation or
semi-quantitation of neutrophils or white
blood cells in the direct examination report?

January 2015

Instruction
Assume that counts of cells identified by these
other descriptors (e.g., “white blood cells”) are
equivalent to counts of neutrophils, unless the
laboratory tells you this is not the case.
Check with the laboratory to get information
about what quantitative ranges the semiquantitative reports correspond to.
Use the following direct examination results to
meet the purulent respiratory secretions
criterion: heavy, 4+, or ≥25 neutrophils per low
power field (lpf) [x100], AND rare, occasional,
few, 1+ or 2+, or ≤10 squamous epithelial cells
per lpf [x100] [19].
In this situation, the purulent secretions
criterion may be met using the specified
quantitative and semi-quantitative thresholds
for neutrophils alone (i.e., heavy, 4+, or ≥25
neutrophils per lpf [x100]).
In this situation, the purulent secretions
criterion may be met using the laboratory’s
specified maximum quantitative threshold for
neutrophils, and/or minimum quantitative
threshold for squamous epithelial cells.
In this situation, a report indicating the
presence of white blood cells, without
quantitation, is sufficient to meet the purulent
secretions criterion.

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Location of attribution: The inpatient location where the patient was assigned on the date of the
VAE, which is further defined as the date of onset of worsening oxygenation.
EXAMPLE: Patient is intubated and ventilated in the Operating Room on hospital day 1,
and then is admitted post-operatively to the SICU on hospital day 1, still on the
ventilator. On hospital day 3, the patient experiences the onset of worsening
oxygenation, manifested by an increase in the daily minimum FiO2 of ≥ 0.20 (20%). On
day 4 (also the 4th day of mechanical ventilation) the patient meets criteria for a VAC.
This is reported to NHSN as a VAC for the SICU.
EXCEPTION:
Transfer Rule: If a VAE develops on the day of transfer or the day following transfer
from one inpatient location to another in the same facility or to a new facility (where the
day of transfer is day 1), the event is attributed to the transferring location. This is called
the Transfer Rule, and examples are shown below:
EXAMPLE: Patient on a ventilator in the SICU who has had improving oxygenation for
3 days is transferred to the MICU, still on the ventilator. On the day of transfer, after the
patient has arrived in the MICU, the patient experiences an acute decompensation,
requiring an increase of 0.30 (30 points) in FiO2 that persists during the following
calendar day. VAC criteria are met on calendar day 2 in the MICU. Because the onset of
worsening oxygenation occurred on the day of transfer to the MICU, the VAC event is
attributed to the SICU.
EXAMPLE: Patient is extubated in the MICU and transferred to the medical stepdown
unit on hospital day 6. The next day, while in the stepdown unit (day 7), the patient
experiences worsening oxygenation and is reintubated and transferred back to the MICU.
Criteria for VAC are met the next day (day 8). In this case, the day prior to extubation
and the day of extubation (hospital days 5 and 6) count as the required 2-day period of
stability or improvement. The day of reintubation (day 7) and the following day (day 8)
count as the required 2-day period of worsening oxygenation. Because the onset of
worsening oxygenation occurred on the day following transfer out of the MICU, the
event is reported to NHSN as a VAC for the MICU.
EXAMPLE: Patient intubated and mechanically ventilated for 8 days in the MSICU of
Hospital A is transferred for further care on day 8 to the MSICU of Hospital B. The
patient was stable on the ventilator in Hospital A from days 3-8. On the day of transfer to
Hospital B (day 1 in Hospital B), the patient’s respiratory status deteriorates. The day
after transfer (day 2 in Hospital B), the patient meets criteria for VAC. The date of the
event is day 1 in Hospital B, the first day of the period of worsening oxygenation meeting
VAE PEEP or FiO2 thresholds. The infection preventionist (IP) from Hospital B calls the
Hospital A IP to report that this patient was admitted to Hospital B with a VAC. This

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VAC should be reported to NHSN for and by Hospital A, and attributed to the Hospital A
MSICU. No additional ventilator days are reported by Hospital A.
REPORTING INSTRUCTIONS (additional guidance may be found in the FAQs at the end of
this chapter):
 Conducting in-plan VAE surveillance means assessing patients for the presence of ALL
events included in the algorithm—from VAC to IVAC to PVAP. At this time, a unit
conducting in-plan VAE surveillance cannot decide, for example, that only surveillance
for VAC (and not for IVAC or PVAP) will be performed.
 There is a hierarchy of definitions within VAE:
o If a patient meets criteria for VAC and IVAC, report as IVAC.
 If a patient meets criteria for VAC, IVAC and PVAP, report PVAP.Pathogens are not
reported for VAC or IVAC events.
 Secondary BSIs are not reported for VAC or IVAC events (refer to VAE Additional FAQ
document for guidance).
 Pathogens may be reported for PVAP events, provided they are isolated or identified
from appropriate specimen types according to the requirements of the algorithm and are
NOT on the list of excluded organisms and culture results:
o Excluded organisms and culture results that cannot be used to meet the PVAP
definitions are as follows: “Normal respiratory flora,” “normal oral flora,” “mixed
respiratory flora,” “mixed oral flora,” “altered oral flora” or other similar results
indicating isolation of commensal flora of the oral cavity or upper respiratory tract;
Candida species or yeast not otherwise specified; coagulase-negative Staphylococcus
species; and Enterococcus species, when isolated from cultures of sputum,
endotracheal aspirates, bronchoalveolar lavage, or protected specimen brushings.
These organisms can be reported as PVAP pathogens if isolated from cultures of lung
tissue or pleural fluid.
o Additionally, because organisms belonging to the following genera are typically
causes of community-associated respiratory infections and are rarely or are not
known to be causes of healthcare-associated infections, they are also excluded, and
cannot be used to meet the PVAP definition when isolated from any eligible
specimen type (to include lung and pleural fluid): Blastomyces, Histoplasma,
Coccidioides, Paracoccidioides, Cryptococcus and Pneumocystis.
 There are three criteria that can be used to meet the PVAP definition:
o Criterion 1: Positive culture meeting specific quantitative or semi-quantitative
threshold (Table 3);
o Criterion 2: Purulent respiratory secretions AND a positive culture NOT
meeting the quantitative or semi-quantitative thresholds specified in Table 3;
o Criterion 3: Positive diagnostic test for Legionella species or selected
respiratory viruses (Figure 4).
 See Table 3 for the required quantitative culture thresholds meeting the PVAP definition.
Note that if your laboratory reports semi-quantitative culture results, you should check

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with your laboratory to confirm that semi-quantitative results match the quantitative
thresholds noted in Table 3.
Table 3. Threshold values for cultured specimens used in the PVAP definition
Specimen collection/technique
Lung tissue
Bronchoscopically (B) obtained specimens
Bronchoalveolar lavage (B-BAL)
Protected BAL (B-PBAL)
Protected specimen brushing (B-PSB)
Nonbronchoscopically (NB) obtained (blind) specimens
NB-BAL
NB-PSB
Endotracheal aspirate (ETA)

Values
≥ 104 cfu/g tissue*
≥ 104 cfu/ml*
≥ 104 cfu/ml*
≥ 103 cfu/ml*
> 104 cfu/ml*
≥ 103 cfu/ml*
≥ 105 cfu/ml*

cfu = colony forming units, g = gram, ml = milliliter
*Or corresponding semi-quantitative result.



Secondary BSIs may be reported for PVAP events, provided that at least one organism
isolated from the blood culture matches an organism isolated from an appropriate
respiratory tract specimen (including respiratory secretions, pleural fluid and lung tissue).
The respiratory tract specimen must have been collected on or after the 3rd day of
mechanical ventilation and within 2 calendar days before or after the day of onset of
worsening oxygenation to be considered as a criterion for meeting the PVAP definitions.
In addition, the positive blood culture must have been collected during the 14-day event
period, where day 1 is the day of onset of worsening oxygenation (refer to VAE
Additional FAQ document for guidance).
o In cases where PVAP is met with only the histopathology criterion and no culture is
performed, and there is also a positive blood culture, a secondary BSI is not reported.
o In cases where a culture of respiratory secretions, pleural fluid or lung tissue is
performed and does not grow an organism that matches an organism isolated from
blood, a secondary BSI is not reported.
NOTE: Candida species or yeast not otherwise specified, coagulase-negative
Staphylococcus species, and Enterococcus species cultured from blood cannot be
deemed secondary to a PVAP, unless the organism was also cultured from pleural
fluid or lung tissue.

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Figure 1: Ventilator-Associated Events (VAE) Surveillance Algorithm
Patient has a baseline period of stability or improvement on the ventilator, defined by ≥ 2 calendar days of stable or decreasing daily minimum*
FiO2 or PEEP values. The baseline period is defined as the 2 calendar days immediately preceding the first day of increased daily minimum PEEP or
FiO2.
*

Daily minimum defined by lowest value of FiO2 or PEEP during a calendar day that is maintained for at least 1 hour.

After a period of stability or improvement on the ventilator, the patient has at least one of the following indicators of worsening oxygenation:
*
1) Increase in daily minimum FiO2 of ≥ 0.20 (20 points) over the daily minimum FiO2 in the baseline period, sustained for ≥ 2 calendar days.
*
†
2) Increase in daily minimum PEEP values of ≥ 3 cmH2O over the daily minimum PEEP in the baseline period , sustained for ≥ 2 calendar days.
*
†

Daily minimum defined by lowest value of FiO2 or PEEP during a calendar day that is maintained for at least 1 hour.
Daily minimum PEEP values of 0-5 cmH2O are considered equivalent for the purposes of VAE surveillance.

Ventilator-Associated Condition (VAC)

On or after calendar day 3 of mechanical ventilation and within 2 calendar days before or after the onset of worsening oxygenation, the patient
meets both of the following criteria:
3

1) Temperature > 38 °C or < 36°C, OR white blood cell count ≥ 12,000 cells/mm or ≤ 4,000 cells/mm .
AND
2) A new antimicrobial agent(s) (see Appendix for eligible antimicrobial agents) is started, and is continued for ≥ 4 calendar days.

Infection-related Ventilator-Associated Complication (IVAC)
On or after calendar day 3 of mechanical ventilation and within 2 calendar days before or after the onset of worsening oxygenation, ONE of the
following criteria is met (taking into account organism exclusions specified in the protocol):
1) Criterion 1: Positive culture of one of the following specimens, meeting quantitative or semi-quantitative thresholds as outlined in
protocol, without requirement for purulent respiratory secretions:
5

Endotracheal aspirate, ≥ 10 CFU/ml or corresponding semi-quantitative result
4

Bronchoalveolar lavage, ≥ 10 CFU/ml or corresponding semi-quantitative result
4

Lung tissue, ≥ 10 CFU/g or corresponding semi-quantitative result
3

Protected specimen brush, ≥ 10 CFU/ml or corresponding semi-quantitative result
2) Criterion 2: Purulent respiratory secretions (defined as secretions from the lungs, bronchi, or trachea that contain >25 neutrophils and
†
<10 squamous epithelial cells per low power field [lpf, x100]) plus a positive culture of one of the following specimens (qualitative
culture, or quantitative/semi-quantitative culture without sufficient growth to meet criterion #1):

Sputum

Endotracheal aspirate

Bronchoalveolar lavage

Lung tissue

Protected specimen brush
†
If the laboratory reports semi-quantitative results, those results must correspond to the above quantitative thresholds. See
additional instructions for using the purulent respiratory secretions criterion in the VAE Protocol.
3) Criterion 3: One of the following positive tests:

Pleural fluid culture (where specimen was obtained during thoracentesis or initial placement of chest tube and NOT from an
indwelling chest tube)

Lung histopathology, defined as: 1) abscess formation or foci of consolidation with intense neutrophil accumulation in
bronchioles and alveoli; 2) evidence of lung parenchyma invasion by fungi (hyphae, pseudohyphae or yeast forms); 3) evidence
of infection with the viral pathogens listed below based on results of immunohistochemical assays, cytology, or microscopy
performed on lung tissue

Diagnostic test for Legionella species

Diagnostic test on respiratory secretions for influenza virus, respiratory syncytial virus, adenovirus, parainfluenza virus,
rhinovirus, human metapneumovirus, coronavirus

January 2015
*Excludes the following:

10-18 Pneumonia (PVAP)
Possible Ventilator-Associated

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Figure 2: Ventilator-Associated Condition (VAC)
Patient has a baseline period of stability or improvement on the ventilator, defined by ≥ 2
calendar days of stable or decreasing daily minimum* FiO2 or PEEP values. The baseline
period is defined as the 2 calendar days immediately preceding the first day of increased
daily minimum PEEP or FiO2.
*

Daily minimum defined by lowest value of FiO2 or PEEP during a calendar day that is maintained for at least 1 hour.

AND
After a period of stability or improvement on the ventilator, the patient has at least one of
the following indicators of worsening oxygenation:
1) Increase in daily minimum* FiO2 of ≥ 0.20 (20 points) over the daily minimum
FiO2 in the baseline period, sustained for ≥ 2 calendar days.
2) Increase in daily minimum* PEEP values of ≥ 3 cmH2O over the daily minimum
PEEP in the baseline period†, sustained for ≥ 2 calendar days.
*

Daily minimum defined by lowest value of FiO2 or PEEP during a calendar day that is
maintained for at least 1 hour.
†

Daily minimum PEEP values of 0-5 cmH2O are considered equivalent for the
purposes of VAE surveillance.

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Figure 3: Infection-related Ventilator-Associated Complication (IVAC)
Patient meets criteria for VAC
AND

On or after calendar day 3 of mechanical ventilation and within 2 calendar days before or
after the onset of worsening oxygenation, the patient meets both of the following criteria:
1) Temperature > 38 °C or < 36°C, OR white blood cell count ≥ 12,000 cells/mm3 or
≤ 4,000 cells/mm3.
AND
2) A new antimicrobial agent(s)* is started, and is continued for ≥ 4 calendar days.
*See Appendix for eligible agents.

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Figure 4: Possible Ventilator-Associated Pneumonia (PVAP)
Patient meets criteria for VAC and IVAC
AND
On or after calendar day 3 of mechanical ventilation and within 2 calendar days before or after
the onset of worsening oxygenation, ONE of the following criteria is met (taking into account
organism exclusions specified in the protocol*):
1) Criterion 1: Positive culture of one of the following specimens, meeting quantitative or
semi-quantitative thresholds as outlined in protocol, without requirement for purulent
respiratory secretions:





Endotracheal aspirate, ≥ 105 CFU/ml or corresponding semi-quantitative result
Bronchoalveolar lavage, ≥ 104 CFU/ml or corresponding semi-quantitative result
Lung tissue, ≥ 104 CFU/g or corresponding semi-quantitative result
Protected specimen brush, ≥ 103 CFU/ml or corresponding semi-quantitative result

2) Criterion 2: Purulent respiratory secretions (defined as secretions from the lungs,
bronchi, or trachea that contain >25 neutrophils and <10 squamous epithelial cells per
low power field [lpf, x100])† plus a positive culture of one of the following specimens
(qualitative culture, or quantitative/semi-quantitative culture without sufficient growth to
meet criterion #1):





†

Sputum
Endotracheal aspirate
Bronchoalveolar lavage
Lung tissue
Protected specimen brush

If the laboratory reports semi-quantitative results, those results must correspond to
the above quantitative thresholds. See additional instructions for using the purulent
respiratory secretions criterion in the VAE Protocol.
3) Criterion 3: One of the following positive tests:
 Pleural fluid culture (where specimen was obtained during thoracentesis or initial
placement of chest tube and NOT from an indwelling chest tube)
 Lung histopathology, defined as: 1) abscess formation or foci of consolidation
with intense neutrophil accumulation in bronchioles and alveoli; 2) evidence of
lung parenchyma invasion by fungi (hyphae, pseudohyphae or yeast forms); 3)
evidence of infection with the viral pathogens listed below based on results of
immunohistochemical assays, cytology, or microscopy performed on lung tissue
 Diagnostic test for Legionella species
 Diagnostic test on respiratory secretions for influenza virus, respiratory syncytial
virus, adenovirus, parainfluenza virus, rhinovirus, human metapneumovirus,
coronavirus
*

Excludes the following: Normal respiratory/oral flora, mixed respiratory/oral flora or equivalent; Candida species or yeast not
otherwise specified; coagulase-negative Staphylococcus species; Enterococcus species (unless isolated from cultures of lung
tissue or pleural fluid). Also excludes the following community-associated respiratory pathogens: Blastomyces, Histoplasma,
Coccidioides, Paracoccidioides, Cryptococcus and Pneumocystis.

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Numerator Data: The Ventilator-Associated Event form (CDC 57.112) is used to collect and
report each VAE that is identified during the month selected for surveillance. The Instructions
for Completion of Ventilator-Associated Event Form includes brief instructions for collection
and entry of each data element on the form. The VAE form includes patient demographic
information and information on the start date and location of initiation of mechanical ventilation.
Additional data include the specific criteria met for identifying VAE, whether the patient
developed a secondary bloodstream infection, whether the patient died, and, where applicable,
the organisms detected and their antimicrobial susceptibilities.
REPORTING INSTRUCTION:
 If no VAEs are identified during the month of surveillance, the Report No Events box must
be checked on the appropriate denominator summary screen, e.g., Denominators for
Intensive Care Unit (ICU)/Other locations (Not NICU or SCA), etc.
Denominator Data: Device days and patient days are used for denominators (see Chapter 16
Key Terms). Ventilator days, which are the numbers of patients managed with ventilatory
devices, are collected daily, at the same time each day, according to the chosen location using the
appropriate form (CDC 57.117 and 57.118). These daily counts are summed and only the total
for the month is entered into NHSN. Ventilator and patient days are collected for each of the
locations monitored. When denominator data are available from electronic sources (e.g.,
ventilator days from respiratory therapy), these sources may be used as long as the counts are not
substantially different (+/- 5%) from manually-collected counts, pre-validated for a minimum of
3 months. Collection of an additional denominator, episodes of mechanical ventilation (EMV), is
optionally available for VAE surveillance beginning in January 2015. The total number of
episodes of mechanical ventilation for each patient eligible for VAE surveillance is reported.
The Instructions for Completion of Ventilator-Associated Event Form includes brief instructions
for collection and entry of each data element on the form.
NOTE: All ventilator days are counted, including ventilator days for patients on mechanical
ventilation for < 3 days, and patients on high frequency ventilation and other therapies excluded
from VAE surveillance. Patients with tracheostomies who are undergoing weaning from
mechanical ventilation using tracheostomy collar trials are included in ventilator day counts as
long as they spend some portion of the day on mechanical ventilation at a time that overlaps with
the daily time during which ventilator day counts are performed.
NOTE: In addition to the total number of patients on ventilators on each day of surveillance, the
number of patients on ventilators who are on the APRV mode of mechanical ventilation or
related modes (which is a subset of all patients on ventilators) should also be indicated on the
appropriate form (CDC 57.117 and 57.118). See FAQ nos. 22 and 23.
Data Analyses: The VAE rate per 1000 ventilator days and the rate per 100 episodes of
mechanical ventilation are calculated by dividing the number of VAEs by the number of

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ventilator days or the number of episodes of mechanical ventilation and multiplying the result by
1000 (ventilator days) or 100 (episodes of mechanical ventilation). Rates that may be appropriate
for use in public reporting, inter-facility comparisons, and pay-for-reporting/pay-for-performance
programs are the overall VAE rate (where the numerator consists of all events meeting at least
the VAC definition) and the “IVAC-plus” rate (where the numerator consists of all events
meeting at least the IVAC definition). Rates that may be appropriate for internal use within an
individual unit or facility include rates of specific event types (e.g., events meeting only the VAC
definition, events meeting only the IVAC definition, events meeting only the PVAP definition),.
The Ventilator Utilization Ratio is calculated by dividing the number of ventilator days by the
number of patient days. These calculations will be performed separately for the different types of
ICUs, SCAs, and other locations in the institution.
***The information that follows regarding the Standardized Infection Ratio (SIR) is for
informational purposes only, until a baseline period of VAE reporting has been established.***
The SIR is calculated by dividing the number of observed events by the number of expected
events. The number of expected events, in the context of statistical prediction, is calculated using
VAE rates from a standard population during a baseline time period as reported in the NHSN
Report.
NOTE: The SIR should be calculated only if the number of expected VAEs (numExp) is ≥
1.
SIR = Observed (O) VAEs / Expected (E) VAEs
While the VAE SIR can be calculated for single locations, the measure also allows you to
summarize your data by multiple locations, adjusting for differences in the incidence of VAEs
among the location types. For example, you can obtain one VAE SIR adjusting for all locations
reported. Similarly, you can obtain one VAE SIR for all specialty care areas in your facility.
Descriptive analysis options of numerator and denominator data are available in the NHSN
application, such as line listings, frequency tables, and bar and pie charts. VAE rates and run
charts are also available. Guides on using NHSN analysis features are available from:
http://www.cdc.gov/nhsn/PS-Analysis-resources/reference-guides.html.

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References
1) Behrendt CE. Acute respiratory failure in the United States: incidence and 31-day survival. Chest
2000;118:1100-5.
2) Kahn JM, Goss CH, Heagerty PJ, et al. Hospital volume and the outcomes of mechanical ventilation. N Engl J
Med 2006;355:41-50.
3) Wunsch H, Linde-Zwirble WT, Angus DC, Hartman ME, Milbrandt EB, Kahn JM. The epidemiology of
mechanical ventilation use in the United States. Crit Care Med 2010;38:1947-53.
4) Rubenfeld GD, Caldwell E, Peabody E, et al. Incidence and outcomes of acute lung injury. N Engl J Med
2005;353:1685-93.
5) Esteban A, Anzueto A, Frutos F, et al. Characteristics and outcomes in adult patients receiving mechanical
ventilation: a 28-day international study. JAMA 2002;287:345-55.
6) Dudeck MA, Weiner LM, Allen-Bridson K, et. al. National Healthcare Safety Network (NHSN) Report, Data
Summary for 2012, Device-associated Module. Am J Infect Control 2013;41:1148-66.
7) Klompas M. Does this patient have ventilator-associated pneumonia? JAMA 2007;297:1583-93.
8) Klompas M. Interobserver variability in ventilator-associated pneumonia surveillance. Am J Infect Control
2010;38:237-9.
9) Klompas M, Kulldorff M, Platt R. Risk of misleading ventilator-associated pneumonia rates with use of
standard clinical and microbiological criteria. Clin Infect Dis 2008;46:1443-6.
10) Zilberberg MD, Shorr AF. Ventilator-associated pneumonia: the clinical pulmonary infection score as a
surrogate for diagnostics and outcome. Clin Infect Dis 2010;51 Suppl 1:S131-5.
11) Girard T, Kress JP, Fuchs BD, et al. Efficacy and safety of a paired sedation and ventilator weaning protocol for
mechanically ventilated patients in intensive care (Awakening and Breathing Controlled trial): a randomised
controlled trial. Lancet 2008;371:126-34.
12) Strøm T, Martinussen T, Toft P. A protocol of no sedation for critically ill patients receiving mechanical
ventilation. Lancet 2010;375:475-80.
13) The Acute Respiratory Distress Syndrome Network. Ventilation with lower tidal volumes as compared with
traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. N Engl J Med
2000;342:1301-8.
14) Schweickert WD, Pohlman MC, Pohlman AS, et al. Early physical and occupational therapy in mechanically
ventilated, critically ill patients: a randomised controlled trial. Lancet 2009;373:1874-82.
15) Magill SS, Klompas M, Balk R, et al. Developing a new, national approach to surveillance for ventilatorassociated events. Critical Care Medicine 2013;41:2467-75.
16) Klompas M, Khan Y, Kleinman K, et al. Multicenter evaluation of a novel surveillance paradigm for
complications of mechanical ventilation. PLoS One 2011;6:e18062.
17) Klompas M, Magill S, Robicsek A, et al. Objective surveillance definitions for ventilator-associated pneumonia.
Crit Care Med;2012, in press.
18) Stedman’s medical dictionary. (28th ed). (2005). Philadelphia: Lippincott, Williams, & Wilkins.
19) Garcia, LS (Ed.). (2010). Clinical Microbiology Procedures Handbook. Herndon, VA: ASM Press, page
3.2.1.16.

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Appendix. List of Antimicrobials Agents Eligible for IVAC, PVAP
Antimicrobial Agent
AMIKACIN
AMPHOTERICIN B
AMPHOTERICIN B LIPOSOMAL
AMPICILLIN
AMPICILLIN/SULBACTAM
ANIDULAFUNGIN
AZITHROMYCIN
AZTREONAM
CASPOFUNGIN
CEFAZOLIN
CEFEPIME
CEFOTAXIME
CEFOTETAN
CEFOXITIN
CEFTAROLINE
CEFTAZIDIME
CEFTIZOXIME
CEFTRIAXONE
CEFUROXIME
CIPROFLOXACIN
CLARITHROMYCIN
CLINDAMYCIN
COLISTIMETHATE
DORIPENEM
DOXYCYCLINE
ERTAPENEM
FLUCONAZOLE
FOSFOMYCIN
GEMIFLOXACIN
GENTAMICIN
IMIPENEM/CILASTATIN
ITRACONAZOLE
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LEVOFLOXACIN
LINEZOLID
MEROPENEM
METRONIDAZOLE
MICAFUNGIN
MINOCYCLINE
MOXIFLOXACIN
NAFCILLIN
OSELTAMIVIR
OXACILLIN
PENICILLIN G
PIPERACILLIN
PIPERACILLIN/TAZOBACTAM
POLYMYXIN B
POSACONAZOLE
QUINUPRISTIN/DALFOPRISTIN
RIFAMPIN
SULFAMETHOXAZOLE/TRIMETHOPRIM
SULFISOXAZOLE
TELAVANCIN
TELITHROMYCIN
TETRACYCLINE
TICARCILLIN/CLAVULANATE
TIGECYCLINE
TOBRAMYCIN
VANCOMYIN, intravenous only
VORICONAZOLE
ZANAMIVIR

January 2015

10-26

Device-associated Module
VAE

VAE FREQUENTLY-ASKED QUESTIONS
1) When should I use VAE? Are there circumstances in which I should still use PNEU?
 VAE surveillance is location based, and restricted to adult inpatient units only.
 Pediatric and neonatal units are excluded from VAE surveillance (even in circumstances
where a pediatric unit may occasionally care for patients who are 18 years of age and
older).
 Locations mapped to mixed age CDC location codes are excluded from VAE
surveillance.
 Ventilated patients who are 18 years of age and older and who are cared for in pediatric
units should be included in PedVAP surveillance.
NOTE: it is NOT recommended to include in VAE surveillance young children housed in adult
ICU locations who are not thought to be physiologically similar to the location’s adult patient
population. Facilities may want to evaluate their location mapping to be sure that locations are
mapped appropriately to the correct CDC location codes. In circumstances where the populations
of adults and children cared for in the same physical location is more mixed (e.g., 50% adult
patients and 50% pediatric patients), it is recommended that facilities weigh the possibility of
establishing a virtual pediatric location for the purposes of surveillance. More information on
virtual locations and location mapping can be found here:
http://www.cdc.gov/nhsn/PDFs/pscManual/15LocationsDescriptions_current.pdf


While on high frequency ventilation or extracorporeal life support, patients are
EXCLUDED from VAE surveillance.
NOTE: Patients who are receiving a conventional mode of mechanical ventilation while
in the prone position and patients who are receiving a conventional mode of mechanical
ventilation while receiving nitric oxide therapy, helium-oxygen mixtures (heliox), or
epoprostenol therapy are INCLUDED.
NOTE: Patients on Airway Pressure Release Ventilation (APRV) and related modes of
mechanical ventilation (see FAQ nos. 22 and 23) are INCLUDED; however, during
periods of time while the patient is on APRV, the VAE period of stability or
improvement on the ventilator and the period of worsening oxygenation should be
determined by changes in FiO2 only, since changes in PEEP as indicated in this
surveillance algorithm may not be applicable to APRV. In addition, patients with VAE
who are on APRV or a related mode of mechanical ventilation at the time of VAE onset
should be indicated as such on the VAE Form (CDC 57.112).




In-plan surveillance for ventilator-associated PNEU may still be conducted for pediatric
patients ONLY (“PedVAP” surveillance).
The PNEU definitions are still available for those units seeking to conduct off-plan
PNEU/VAP surveillance for patients of any age.

January 2015

10-27

Device-associated Module
VAE

2) I am having difficulty visualizing how to arrange the VAE data elements to facilitate easy
identification of events. Can you provide some additional guidance?
 For units in which VAE surveillance will be conducted manually, we recommend that
you organize the necessary data elements in a table or spreadsheet to assist in identifying
VAEs. There are a number of different ways in which to organize the data – you may
consider limiting your spreadsheet to just include the daily minimum PEEP and FiO2
values, and then, if a VAC event is identified, utilize other data sources to gather
information on the data elements included in the IVAC, PVAP definitions. Alternatively,
you may choose to include columns for all data elements (from VAC through PVAP) in a
single spreadsheet.
NOTE: For most patients under surveillance for VAE, the only data elements you will
need to record are the ventilator days, minimum daily PEEP, and minimum daily FiO2.
The maximum and minimum daily temperatures and white blood cell counts only need to
be recorded for those patients who are identified as having met criteria for VAC. The
antimicrobial criterion only needs to be assessed for those patients with VAC and with an
abnormal temperature or white blood cell count that meets the criteria within the IVAC
definition. Microbiology and related data elements included as criteria in the PVAP
definitions only need to be assessed for those patients who have met the IVAC definition.
NOTE: Keep in mind that the baseline period of stability or improvement on the
ventilator is defined as the 2 calendar days immediately preceding the first day of
increased daily minimum PEEP or FiO2, and must be characterized by ≥ 2 calendar days
of stable or decreasing daily minimum FiO2 or PEEP values (i.e., the daily minimum
PEEP or FiO2 on the second day of the baseline period of stability or improvement must
be equal to or less than the daily minimum PEEP or FiO2 on the first day of the baseline
period of stability or improvement). Keep in mind, too, that PEEP values of 0 to 5
cmH2O are considered equivalent for the purposes of VAE surveillance. This means that
any daily minimum value of 0 to 5 cmH2O will be evaluated as if it were 5 cmH2O when
determining whether a VAC has occurred or not. Also, the daily minimum PEEP or FiO2
is defined as the lowest setting during a calendar day that is maintained for at least 1
hour.
EXAMPLE: In the table below, the data elements used to meet VAC, IVAC and PVAP
definitions are organized in a fashion that facilitates identification of an event,
highlighted in the shaded region. In this example, MV days 3 and 4 constitute the
baseline period, with stable minimum PEEP of 5 cmH2O on each day. On MV days 5 and
6, the daily minimum PEEP is 8 cmH2O, which meets the VAC criterion for worsening
oxygenation. If we scan across the table, we can see that the IVAC temperature/white
blood cell count criterion is not met (there are no temperatures < 36°C or > 38°C, and no
white blood cell counts ≤ 4,000 cells/mm3 or ≥ 12,000 cells/mm3) – so even though the
patient was started on a new antimicrobial agent and continued on that agent for 4
calendar days, IVAC is not met. Therefore, this event would be reported as a VAC, with
the date of event being MV day 5.
January 2015

10-28

Device-associated Module
VAE

Patient

MV Day

PEEPmin

FiO2min

Tempmin

Tempmax

WBCmin

WBCmax

Abx

Specimen

Polys / Epis

Organism

VAE

1.0

37.1

37.6

4.3

None

0.60

36.8

37.2

4.6

None

0.40

37.0

37.9

5.4

None

0.40

36.5

37.3

9.2

Yes

0.50

36.3

36.9

8.4

Yes

ETA

≥ 25 / ≤ 10

S.aureus

VAC

0.40

37.2

37.5

8.5

8.8

Yes

0.40

37.8

37.9

7.6

Yes

MV = mechanical ventilation. PEEPmin = Daily minimum PEEP. FiO2min = Daily minimum FiO2. Tempmin = Daily minimum temperature. Tempmax = Daily
maximum temperature. WBCmin = Daily minimum white blood cell count. WBCmax = Daily maximum white blood cell count. Abx = antimicrobial agents. Polys
/ epis = Polymorphonuclear leukocytes and squamous epithelial cells from respiratory specimen.

EXAMPLE: In the table below, by scanning across the data elements, you can see that
there are no periods in which there is a stable, 2-day baseline period followed by a 2-day
period where the PEEP or FiO2 are increased 3 cmH2O or 20 points over baseline. On
MV days 2 and 3, the PEEP values are 7 cmH2O and 6 cmH2O respectively, and then
increase to 9 cmH2O on MV days 4 and 5 – but the difference between day 4 or day 5 and
day 2 is only 2 cmH2O, rather than the required 3 cmH2O. Also, the gradual increase in
FiO2 from the time of initiation of mechanical ventilation means that there are not two
days on which the FiO2 is at least 20 points higher than on the 2 previous days. Therefore,
although the temperature and white blood cell counts exceed the required thresholds for
IVAC on several occasions, and the patient appears to have received a new antimicrobial
agent for several days in the setting of a positive blood culture, the VAC definition is not
met, and so no VAE is reported.
Patient

MV Day

PEEPmin

FiO2min

Tempmin

Tempmax

WBCmin

WBCmax

Abx

Specimen

Polys / Epis

Organism

VAE

0.30

37.1

37.6

4.3

None

0.30

36.8

37.2

4.6

None

0.45

37.0

37.9

5.4

None

0.45

36.5

37.3

9.2

None

0.60

36.3

36.9

8.4

None

ETA

≥ 25 / ≤ 10

S.aureus

0.60

37.2

37.5

8.5

8.8

None

0.75

37.8

37.9

7.6

None

0.75

38.2

38.4

10.5

11.9

Yes

Blood

S. aureus

0.80

38.5

38.9

12.7

Yes

0.75

37.4

38.1

12.9

Yes

0.70

37.2

37.9

9.4

Yes

0.60

37.3

37.5

9.5

Yes

0.60

37.2

37.8

8.2

Yes

0.60

37.0

37.7

8.6

Yes

3) Is there a hierarchy of reporting for VAE? How do I know whether to report a VAC, an
IVAC or a PVAP?
January 2015

10-29

Device-associated Module
VAE



Conducting in-plan VAE surveillance means assessing patients for the presence of ALL
events included in the algorithm—from VAC to IVAC to PVAP. At this time, a unit
participating in in-plan VAE surveillance cannot decide, for example, that only
surveillance for VAC (and not for IVAC or PVAP) will be performed.
There is a hierarchy of definitions within VAE:
o If a patient meets criteria for VAC and IVAC, report as IVAC.
o If a patient meets criteria for VAC, IVAC and PVAP, report PVAP.

4) How do I determine the duration of a VAE? Can a patient have more than one VAE during a
hospitalization?
 Patients may have multiple VAEs during a single hospitalization. The event period is
defined by the 14-day period that starts on the date of onset of worsening oxygenation.
VAE criteria met during that 14-day period are attributed to the current VAE.
EXAMPLE: Patient is intubated and mechanical ventilation is initiated in the MICU (day
1). The patient is stable during the following 4 calendar days (days 2 through 5). On days
6 and 7 the patient’s minimum daily FiO2 is increased more than 0.20 (20 points) over
baseline, therefore meeting the VAC FiO2 threshold. The VAC episode is defined by the
period encompassing days 6 through 19 (14 days, starting on day 1 of worsening
oxygenation, which in this case is day 6). If the patient were to experience a period of
stability or improvement on the ventilator on days 18 and 19, followed by another 2-day
period of worsening on days 20 and 21, a new VAE would be reported, since the second
period of worsening oxygenation has occurred more than 14 days after the start of the
initial period of worsening oxygenation.
5) Sometimes patients are intubated, extubated, and reintubated several times during a single
hospitalization. How do I define an episode of mechanical ventilation, and can a VAE occur
in a patient who has recently been extubated?
 An episode of mechanical ventilation is defined as a period of days during which the
patient was mechanically ventilated for some portion of each consecutive day during the
period.
EXAMPLE: A patient is intubated and mechanically ventilated on hospital day 1. The
patient remains on mechanical ventilation from hospital day 2 through 12 noon on
hospital day 6. At noon on hospital day 6, the patient is extubated. The patient remains
extubated on hospital day 7, and is then reintubated on hospital day 8. In this case, the
first episode of mechanical ventilation is defined by days 1 through 6. Since the patient
was extubated on day 6 and remained extubated for a full calendar day on day 7, the reintubation of the patient on day 8 defines the start of a second episode of mechanical
ventilation. See figure, below.
Hosp Day No.
MV Episode
MV Day No.

January 2015

1
1
1

2
1
2

3
1
3

4
1
4

5
1
5

10-30

6
1
6—extubated

7
---

8
2
1--reintubated

9
2
2

10
2
3

Device-associated Module
VAE

Hosp Day No.

6
at noon

1 full calendar day off mechanical ventilation, followed by reintubation,
defines a new episode of mechanical ventilation.

EXAMPLE: A patient is intubated and mechanically ventilated on hospital day 1. The
patient remains on mechanical ventilation from hospital day 2 through hospital day 6 at
12 noon. At noon on hospital day 6, the patient is extubated. The patient is reintubated at
9 pm on hospital day 7, and remains intubated and mechanically ventilated till 2 pm on
day 10. The patient is extubated at 2 pm on day 10 and remains extubated until hospital
discharge on day 15. In this case, there is only a single episode of mechanical ventilation,
defined by days 1 through 10, because the patient was extubated on day 6 but reintubated
the next calendar day (day 7). See figure, below.
Hosp Day No.
MV Episode

1
1

2
1

3
1

4
1

5
1

MV Day No.

6
1
6—extubated at
noon

7
1
7—reintubated
at 9 pm

8
1

9
1

10
1
10—extubated
at 2 pm

Patient was reintubated on the calendar day following extubation (days 6-7). Because there is not 1
calendar day off mechanical ventilation, there is only 1 episode of mechanical ventilation.



A VAE can occur in a patient who has been extubated and is then reintubated, subject to
the amount of time the patient was off the ventilator, as noted in the examples below.
EXAMPLE: A patient is intubated and mechanically ventilated on hospital day 1. The
patient remains on mechanical ventilation from hospital day 2 through 12 noon on
hospital day 6. At noon on hospital day 6, the patient is extubated. The patient remains
extubated on hospital day 7, and is then reintubated on hospital day 8. In this case,
because the patient has been extubated for 1 full calendar day (day 7), the “VAE clock”
starts over with reintubation on hospital day 8. To meet VAE during this second episode
of mechanical ventilation, the patient would have to have at least 2 days of stability or
improvement and at least 2 days of worsening oxygenation on the ventilator; therefore,
the earliest date on which the patient could meet VAE criteria would be hospital day 11
(stable or improving settings on days 8 and 9, increased ventilator settings on days 10 and
11). The VAE event date would be reported as day 10—the first day of worsening
oxygenation meeting VAE criteria. See figure, below.

Hosp Day No.
MV Episode

1
1

2
1

3
1

4
1

5
1

MV Day No.

VAE Criterion

January 2015

6
1
6—extubated
at noon

7
--

10-31

8
2
1-reintubated
Day 1 of
stability or
improvement

9
2

10
2

11
2

Day 2 of
stability or
improvement

Day 1 of
worsening
oxygenation

Day 2 of
worsening
oxygenation

Device-associated Module
VAE

EXAMPLE: A patient is intubated and mechanically ventilated on hospital day 1. The
patient remains on mechanical ventilation from hospital day 2 through 12 noon on
hospital day 6, when the patient is extubated. The patient is reintubated at 9 pm on
hospital day 7. In this case, there is no “new” episode of mechanical ventilation, since
there was not a full, ventilator-free calendar day. Therefore, the period of worsening
oxygenation may be determined to have started on day 7, the day of reintubation, as long
as PEEP or FiO2 criteria are met. PEEP and FiO2 data from hospital days 5 and 6
(through the time of extubation) may be used to determine whether a period of stability
and improvement occurred, and these data may be compared to PEEP and FiO2 data
obtained from the time of reintubation on day 7 and beyond to determine whether at least
2 days of worsening oxygenation occurred. The earliest that the patient could meet VAE
criteria would be day 8 (assuming stable or improving ventilator settings on days 5 and 6,
and two days of worsening oxygenation meeting criteria on days 7 and 8). The VAE
event date would be reported as day 7—the first day of worsening oxygenation meeting
VAE criteria. See figure, below.
Hosp Day No.
MV Episode

1
1

2
1

3
1

4
1

5
1

MV Day No.

5
Day 1 of
stability or
improvement

VAE Criterion



6
1
6—extubated
at noon
Day 2 of
stability or
improvement

7
1
7—reintubated
at 9 pm
Day 1 of
worsening
oxygenation

8
1

9
1

10
1

Day 2 of
worsening
oxygenation

A patient may also meet criteria for VAC while intubated, and then meet criteria for
IVAC (or PVAP) following extubation.
EXAMPLE: A patient is intubated and mechanically ventilated on hospital day 1. The
patient remains on mechanical ventilation till 11 am on hospital day 10, when the patient
is extubated. Criteria for VAC are met during the episode of mechanical ventilation,
based on 2 days of stability or improvement (MV days 5 and 6) followed by 2 days of
worsening oxygenation (MV days 7 and 8). The date of the event is MV day 7, the day of
onset of worsening oxygenation. Within the 2 days before and 2 days after the day of
onset of worsening oxygenation, the patient has a temperature of 38.4°C, and a new
antimicrobial agent is started (meropenem, on MV day 9—see FAQ no. 6-10). The new
antimicrobial agent is continued for at least 4 days (hospital days 8 through 11).
Therefore, even though the patient was extubated on hospital day 10 and remained
extubated on hospital day 11 (the day on which all IVAC criteria were fulfilled), the
event should be reported as an IVAC. See figure, below.

Hosp Day No.
MV Day No.

4
4

VAE Criterion
-Antimicrobial

Ceftriaxone

January 2015

5
5

6
6

7
7

8
8

Day 1 of
stability or
improvement
Ceftriaxone

Day 2 of
stability or
improvement
Ceftriaxone

Day 1 of
worsening
oxygenation
Ceftriaxone

Day 2 of
worsening
oxygenation
Meropenem

10-32

9
9

10
Extubated
at 11 am

11
--

Temp 38.4°C

Meropenem

Device-associated Module
VAE

Hosp Day No.
agent

Patient has fulfilled all IVAC criteria, and
IVAC should be reported. Date of the
IVAC event is hospital day/MV day 7.

6) What antimicrobial agents are included in the IVAC definition?
 See the Appendix for a list of the antimicrobial agents eligible for consideration in the
IVAC definition (as well as the PVAP definitions).
 See Table 1 for eligible routes of administration.
7) How do I figure out if an antimicrobial agent is “new” for the IVAC definition?
 A new antimicrobial agent is defined as any agent listed in the Appendix that is initiated
on or after 3 days of mechanical ventilation AND in the VAE Window Period (defined
by the two days before, the day of, and the two days after the onset date of the VAE—as
long as all of these days are on or after the 3rd day of mechanical ventilation). The agent
is considered new for the purposes of this definition if it was NOT given to the patient on
either of the 2 days preceding the current start date. The agent must be administered via
one of the routes listed in Table 1. See the example in the figure below:
MV Day No.
VAE Criterion

7
Onset (day 1) of worsening
oxygenation meeting VAE PEEP
or FiO2 thresholds

8
Day 2 of worsening oxygenation
meeting VAE PEEP or FiO2
thresholds

Example of the 5-day period during which the first dose of a new antimicrobial
agent must be given to meet requirements of IVAC definition

January 2015

10-33

Device-associated Module
VAE

EXAMPLE: A single dose of intravenous vancomycin is given to a patient on the
VAE onset date (which is the day of onset of worsening oxygenation meeting
VAE criteria, in this case MV day 7), and was not given to the patient during the
2 previous days (MV days 5 and 6). Vancomycin is therefore considered a new
antimicrobial agent (see figure below).

MV Day No.
VAE Criterion

4
--

Antimicrobial
agent

None

5
Day 1 of
stability or
improvement

6
Day 2 of
stability or
improvement

None

7
Day 1 of
worsening
oxygenation
Single dose of
vancomycin
ordered and
administered

8
Day 2 of
worsening
oxygenation

None

Single dose of
vancomycin
ordered and
administered

A single dose of vancomycin is ordered and administered to the patient within the
period defined by the two days before, the day of, and the two days after the VAE onset
date. Note that no vancomycin was given in the 2 preceding days, and so vancomycin is
a “new” antimicrobial agent for the purposes of the VAE definition.

EXAMPLE: If meropenem is given to a patient on the VAE onset date (which is
the day of onset of worsening oxygenation meeting VAE criteria, in this case MV
day 7), and was not given to the patient during the 2 previous days (MV days 5
and 6), then meropenem is considered a new antimicrobial agent (see figure
below). Note that the patient is also receiving ceftriaxone, and receives doses
during the 5-day period around the onset of worsening oxygenation (first dose
during the 5-day period was on MV day 5). However, because ceftriaxone was
given to the patient the day before the 5-day period (on MV day 4), ceftriaxone
does not count as a new antimicrobial agent for the purposes of the IVAC
definition.

MV Day No.
VAE Criterion

4
--

Antimicrobial
agent

Ceftriaxone

5
Day 1 of
stability or
improvement

6
Day 2 of
stability or
improvement

7
Day 1 of
worsening
oxygenation

8
Day 2 of
worsening
oxygenation

Ceftriaxone

Meropenem

First dose of meropenem during the 5-day period around the onset of worsening
oxygenation. Note that no meropenem was given in the 2 preceding days, and so
meropenem is a “new” antimicrobial agent for the purposes of the VAE definition.

January 2015

10-34

Device-associated Module
VAE

8) I have figured out that a new antimicrobial agent was given to the patient. How do I
determine whether it was continued for 4 days?
 Make sure you are using the Medication Administration Record. You need to know
which antimicrobial agents were actually administered to the patient. Antimicrobial
orders or dispensing information is not sufficient.
 You do not need to know the dose or frequency of administration.
 Four consecutive Qualifying Antimicrobial Days (QADs)—starting within the VAE
Window Period—are needed to meet the IVAC criterion. A QAD is a day on which the
patient was administered an antimicrobial agent that was determined to be “new” within
the VAE Window Period. Days between administrations of a new antimicrobial agent
also count as QADs as long as there is a gap of no more than 1 calendar day between
administrations of the same antimicrobial agent. For example, if levofloxacin is given on
VAE Day 1, has not been given in the 2 preceding calendar days, and is given again on
VAE Days 3, 5 and 7, there are 7 QADs—because the days between levofloxacin doses
also count as QADs.
 The requirement for 4 consecutive QADs can be met with 4 days of therapy with the
same antimicrobial (with a gap of no more than 1 calendar day between administrations
of that antimicrobial)—or it can be met with 4 days of therapy with multiple
antimicrobial agents, as long as each antimicrobial was started within the VAE Window
Period.

EXAMPLE: In the figure below, meropenem would meet the antimicrobial
criterion of the IVAC definition because at least one dose was given on 4
consecutive days.
MV Day No.
VAE Criterion

1
--

3
Day 2 of
stability or
improvement
Ceftriaxone

4
Day 1 of
worsening
oxygenation
Meropenem

5
Day 2 of
worsening
oxygenation
Meropenem

Ceftriaxone

2
Day 1 of
Stability or
improvement
Ceftriaxone

Antimicrobial
agent
QAD

Meropenem

Yes

EXAMPLE: In the figure below, the 3 drugs shown in bold lettering all qualify as
new antimicrobial agents, and therefore the antimicrobial criterion of IVAC is
met, since the patient is given 4 consecutive days of new antimicrobial agents.
MV Day No.
VAE Criterion

1
--

Ceftriaxone

2
Day 1 of
Stability or
improvement
Ceftriaxone

3
Day 2 of
stability or
improvement
Ceftriaxone

4
Day 1 of
worsening
oxygenation
Meropenem

5
Day 2 of
worsening
oxygenation
Imipenem

Antimicrobial
agent
QAD

Yes

January 2015

10-35

Piperacillin/
tazobactam
Yes

Device-associated Module
VAE

EXAMPLE: In the figure below, levofloxacin is a new antimicrobial agent (it was
started during the VAE Window Period, on MV day 3, and was not given in the 2
days preceding the first day of administration). There are gaps of no more than 1
calendar days between days on which levofloxacin is given, and so the
intervening days also count as QADs. In this example, there are 5 QADs (MV
days 3-7); therefore the antimicrobial criterion of IVAC is met.
MV Day No.
VAE Criterion

Antimicrobial
agent
QAD

1
--

2
Day 1 of
Stability or
improvement

3
Day 2 of
stability or
improvement
Levofloxacin

4
Day 1 of
worsening
oxygenation

Yes

5
Day 2 of
worsening
oxygenation
Levofloxacin

Yes

Levofloxacin
Yes

9) There are many patients in my ICU with renal insufficiency and/or who are receiving
hemodialysis. These patients may receive certain antimicrobial agents on an infrequent
dosing schedule (for example, every 48 hours). How do I determine whether they have
received 4 consecutive days of new antimicrobial therapy?
 See above. You do not need to know the patient’s renal function, the dose of the
antimicrobial agent, or the frequency of administration. The antimicrobial criterion rules
remain the same, regardless of whether patients have renal dysfunction or not.
10) What if the patient is being given one-time doses of intravenous vancomycin? How do I take
that into account when using the IVAC surveillance definition?
 The rules for determining whether the antimicrobial criterion is met do not require that
you know the dose or frequency of administration.
 Make sure that vancomycin qualifies as a new antimicrobial agent—that it was not given
in the 2 days preceding the day on which vancomycin was given during the VAE
Window Period.
 Check to see whether there are 4 consecutive QADs with vancomycin; if there are gaps
of no more than 1 calendar day between days on which vancomycin is given, the
intervening days may be counted as QADs. If there are gaps of longer than 1 calendar
day between days of vancomycin therapy, the requirement for 4 consecutive QADs
cannot be met using vancomycin alone—but make sure to check whether the 4
consecutive QAD requirement is met by considering any other antimicrobials being
administered to the patient.
EXAMPLE: A patient is given a single dose of vancomycin 1 gram IV on MV
day 5. Since vancomycin was started on or after day 3 of mechanical ventilation,
and no vancomycin was administered on MV days 2, 3 or 4, vancomycin qualifies
as a new antimicrobial agent. A second, single dose of vancomycin 1 gram IV is
administered on MV day 8. Because there is a gap of more than 1 calendar day
between days of vancomycin administration (there is a gap of 2 days in this
January 2015

10-36

Device-associated Module
VAE

example), the requirement for 4 consecutive QADs is not met, and therefore the
IVAC antimicrobial criterion is not met.
MV Day No.
VAE Criterion

2
--

3
--

Antimicrobial
agent

None

4
Day 1 of
Stability or
improvement
None

QAD

5
Day 2 of
stability or
improvement
Vancomycin 1
gram IV x 1
dose
Yes

6
Day 1 of
worsening
oxygenation
None

7
Day 2 of
worsening
oxygenation
None

Vancomycin 1
gram IV x 1
dose
Yes

None

11) Can I report pathogens or secondary BSIs for VAC and IVAC?
 Pathogens are NOT reported for VAC or IVAC events.
 Secondary BSIs are NOT reported for VAC or IVAC events.
EXAMPLE: A patient hospitalized and mechanically-ventilated in the MICU for
14 days develops worsening oxygenation following a 7-day period of stability on
the ventilator. VAC criteria are met on hospital day 15 (stable ventilator settings
on days 12 and 13, increased ventilator settings on days 14 and 15). The onset
date is day 14. The white blood cell count is noted to be 15,500 cells/mm3 on day
14. Meropenem and intravenous vancomycin are begun on day 15, administered
through the patient’s right-sided central line, which was inserted on ICU
admission. The antibiotics continue to be administered on day 18, meeting IVAC
criteria. Endotracheal aspirate cultures done on days 15 and 16 grow scant upper
respiratory flora. A blood culture collected on day 15 is positive for Klebsiella
oxytoca. There are no other signs or symptoms of infection. This patient should be
reported as having an IVAC and a central line-associated BSI. The BSI cannot be
reported as secondary to the IVAC event.
12) Can I report pathogens for PVAP?
 Pathogens may be reported for PVAP events, provided they are isolated or identified
from appropriate specimen types according to the requirements of the algorithm and are
NOT on the list of excluded organisms and culture results:
o Excluded organisms and culture results that cannot be used to meet the PVAP
definitions are as follows: “Normal respiratory flora,” “normal oral flora,”
“mixed respiratory flora,” “mixed oral flora,” “altered oral flora” or other
similar results indicating isolation of commensal flora of the oral cavity or
upper respiratory tract; Candida species or yeast not otherwise specified;
coagulase-negative Staphylococcus species; and Enterococcus species, when
isolated from cultures of sputum, endotracheal aspirates, bronchoalveolar
lavage, or protected specimen brushings.

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NOTE: When Candida species or yeast not otherwise specified, coagulase-negative
Staphylococcus species or Enterococcus species are isolated from cultures of lung tissue
or pleural fluid, these organisms may be reported as PVAP pathogens.
Additionally, because organisms belonging to the following genera are usually causes of
community-associated respiratory infections and rarely or are not known to be causes of
healthcare-associated infections, they are also excluded, and cannot be used to meet the
PVAP definition when isolated from any eligible specimen type (to include lung and
pleural fluid): Blastomyces, Histoplasma, Coccidioides, Paracoccidioides, Cryptococcus
and Pneumocystis.


See Table 3 for the required quantitative culture thresholds associated with various
specimen types in the PVAP definition. Note that if your laboratory reports semiquantitative culture results, you should check with your laboratory to confirm that semiquantitative results match the quantitative thresholds noted in Table 3.

13) Can I report secondary BSIs for PVAP?
 Secondary BSIs may be reported for PVAP events, provided that the organism isolated
from the blood culture matches an organism isolated from an appropriate respiratory tract
specimen (including respiratory secretions, pleural fluid and lung tissue). The respiratory
tract specimen must have been collected within 2 calendar days before or after the day of
onset of worsening oxygenation to be considered as a criterion for meeting the PVAP
definitions. In addition, the positive blood culture must have been collected during the
14-day event period, where day 1 is the day of onset of worsening oxygenation.
o In cases where PVAP is met with only the histopathology criterion and no culture
is performed, and there is also a positive blood culture, a secondary BSI is not
reported.
o In cases where a culture of respiratory secretions, pleural fluid or lung tissue is
performed and does not grow an organism that matches an organism isolated from
blood, a secondary BSI is not reported.
NOTE: Candida species or yeast not otherwise specified, coagulase-negative
Staphylococcus species, and Enterococcus species cultured from blood cannot be
deemed secondary to a PVAP, unless the organism was also cultured from pleural
fluid or lung tissue.
EXAMPLE: Patient hospitalized and mechanically ventilated in the MICU for 14
days develops worsening oxygenation following a 7-day period of stability on the
ventilator. VAC criteria are met on hospital day 15 (stable ventilator settings on days
12 and 13, increased ventilator settings on days 14 and 15). The onset date is day 14.
The white blood cell count is noted to be 15,500 cells/mm3 on day 14. Meropenem
and vancomycin are begun on day 15, administered through the patient’s right-sided
central line (inserted on ICU admission). The antibiotics continue to be administered
on day 18, meeting IVAC criteria. Endotracheal aspirate specimens collected on days
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15 and 16 grow ≥ 105 CFU/ml Klebsiella oxytoca. A blood culture collected on day
15 is positive for K. oxytoca. This patient should be reported as having a PVAP with a
secondary BSI due to K. oxytoca.
EXAMPLE: Patient hospitalized and mechanically ventilated in the MICU for 14
days develops worsening oxygenation following a 7-day period of stability on the
ventilator. VAC criteria are met on hospital day 15 (stable ventilator settings on days
12 and 13, increased ventilator settings on days 14 and 15). The onset date is day 14.
The white blood cell count is noted to be 15,500 cells/mm3 on day 14. Meropenem
and vancomycin are begun on day 15, administered through the patient’s right-sided
central line (inserted on ICU admission). The antibiotics continue to be administered
on day 18, meeting IVAC criteria. A thoracentesis is performed on day 15 at the
patient’s bedside using aseptic technique. Pleural fluid is sent for culture and grows
Candida albicans. A blood culture collected on day 16 is positive for C. albicans.
This patient should be reported as having a PVAP with a secondary BSI due to C.
albicans.
EXAMPLE: Patient hospitalized and mechanically ventilated in the MICU for 14
days develops worsening oxygenation following a 7-day period of stability on the
ventilator. VAC criteria are met on hospital day 15 (stable ventilator settings on days
12 and 13, increased ventilator settings on days 14 and 15). The onset date is day 14.
The white blood cell count is noted to be 15,500 cells/mm3 on day 14. Meropenem
and vancomycin are begun on day 15, administered through the patient’s right-sided
central line (inserted on ICU admission). The antibiotics continue to be administered
on day 18, meeting IVAC criteria. An endotracheal aspirate collected on day 15 is a
good quality specimen, with ≥ 25 neutrophils and ≤ 10 squamous epithelial cells per
low power field, and grows Staphylococcus aureus (qualitative result). A blood
culture collected on day 24 is positive for S. aureus and for coagulase-negative
staphylococci (CoNS). This patient should be reported as having a PVAP, with S.
aureus reported as the pathogen. A secondary BSI should also be reported for the
PVAP, since the positive blood culture was collected within the 14-day period of the
VAE, and an organism isolated from blood (S. aureus) matched an organism isolated
from culture of the endotracheal aspirate. The CoNS also isolated from the blood
culture on day 24 is not reported as a pathogen for the PVAP because it is an
excluded organism.
14) Can I only report pathogens if they are isolated in cultures of appropriate specimens? What
about pathogens identified by non-culture-based diagnostic testing?
 PVAP incorporates results of non-culture-based microbiological diagnostic testing. For
PVAP, pathogens that are grown in culture OR selected pathogens that are identified as a
result of other laboratory testing (e.g., antigen testing, PCR, immunohistochemistry, etc.)
should be reported. Do not limit reporting to just those organisms isolated in culture. For
example, influenza A identified by polymerase chain reaction (PCR) in a patient meeting
PVAP criteria should be reported as a pathogen for that event.
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15) The “PVAP” criterion 3 includes “positive diagnostic tests” for Legionella species, and
selected viruses. What kinds of diagnostic tests can be used to meet the definition?
 Diagnostic testing practices may vary from facility to facility and change over time as
better tests are developed. Listed here are some examples of diagnostic tests for specific
pathogens included in the PVAP definition. Positive results of these tests may be used in
meeting the PVAP definition. Your facility may use other testing methods; positive
results obtained using these methods may also be appropriate for use in meeting the
PVAP definition. If you have a question regarding a diagnostic test method, check with
your laboratory.
 For Legionella species, positive results of any of the following, performed on the
appropriate specimen: urinary antigen, Legionella-specific respiratory culture, paired
serology (4-fold rise in titer between acute and convalescent specimens), direct
fluorescent antibody stain, immunohistochemistry stain, or nucleic acid detection assays
(such as PCR) performed on a respiratory specimen.
 For respiratory viruses (influenza, respiratory syncytial virus [RSV], parainfluenza
viruses, human metapneumovirus, coronaviruses, rhinoviruses and adenovirus), positive
results for any of the following:
o Performed on an appropriate respiratory specimens – PCR or other viral
nucleic acid detection methods, antigen detection methods, including rapid
tests, viral cell culture, or
o Performed on appropriate pathologic specimens – immunohistochemical
assays, cytology, microscopy, or
o Performed on appropriately timed paired sera (acute and convalescent) –
serological assays demonstrating seroconversion or a significant rise in
antibody titer.
16) What about pneumonitis that occurs in a mechanically-ventilated patient and is determined to
be due to herpes simplex virus (HSV) or cytomegalovirus (CMV)? Can these infections be
reported as VAEs?
 In most cases pneumonitis due to HSV and CMV represents reactivation of a latent
infection, and therefore would not be considered healthcare-associated, according to the
NHSN definition of a healthcare-associated infection.
17) Are there any culture results or microorganisms that CANNOT be used to meet the PVAP
definitions?
 The following pathogens and culture results may NOT be used to meet the definitions
and may NOT be reported as causes of PVAP when they are obtained from cultures of
sputum, endotracheal aspirates, bronchoalveolar lavages or protected specimen
brushings:
o Culture results reported as “Normal respiratory flora,” “normal oral flora,”
“mixed respiratory flora,” “mixed oral flora,” “altered oral flora” or other similar
results indicating isolation of commensal flora of the oral cavity or upper
respiratory tract.
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o Candida species or yeast not otherwise specified
o Coagulase-negative Staphylococcus species
o Enterococcus species
NOTE: These organisms are excluded because they are common upper respiratory tract
commensals, colonizers or contaminants, and are unusual causes of VAP. Their exclusion
from the surveillance definitions should NOT be used in clinical decision-making
regarding patient treatment. Providers must independently determine the clinical
significance of these organisms isolated from respiratory specimen cultures and the need
for treatment.
NOTE: When Candida species or yeast not otherwise specified, coagulase-negative
Staphylococcus species or Enterococcus species are isolated from cultures of lung tissue
or pleural fluid, these organisms may be reported as PVAP pathogens.



Additionally, because organisms belonging to the following genera are typically causes
of community-associated respiratory infections and are rarely or are not known to be
causes of healthcare-associated infections, they are also excluded, and cannot be used to
meet the PVAP definition when isolated from any eligible specimen type (to include lung
and pleural fluid): Blastomyces, Histoplasma, Coccidioides, Paracoccidioides,
Cryptococcus and Pneumocystis.
When sputum, endotracheal aspirate, bronchoalveolar lavage or protected specimen
brushing culture results are mixed and contain one or more of the excluded pathogens in
addition to one or more non-excluded pathogens, the culture may be used to meet the
PVAP definition (depending on whether a qualitative, semi-quantitative or quantitative
culture was performed, and whether the semi-quantitative or quantitative cfu/ml
thresholds were met) BUT only the non-excluded pathogen(s) should be reported.
EXAMPLE: Patient intubated and mechanically ventilated in the MSICU meets IVAC
criteria on day 8 of mechanical ventilation. On the day after the onset of worsening
oxygenation, an endotracheal aspirate is collected. The Gram stain shows ≥ 25
neutrophils and ≤ 10 squamous epithelial cells per low power field, and the culture grows
“heavy Staphylococcus aureus” and “heavy Candida albicans.” This patient should be
reported as having a PVAP (criterion1) due to Staphylococcus aureus – as long as the
semi-quantitative result “heavy” is equivalent to the quantitative threshold of ≥ 105
cfu/ml for endotracheal aspirates. If the semi-quantitative result is not equivalent to the
the quantitative threshold of ≥ 105 cfu/ml for endotracheal aspirates, the patient should
still be reported as PVAP (criterion 2). Candida albicans from the endotracheal aspirate
culture is not reported, because it is an excluded result.

18) What about pleural fluid cultures and lung tissue cultures? Can I report any pathogen isolated
from a lung tissue culture, or from a pleural fluid culture, assuming the specimen was
obtained during thoracentesis or at the time of chest tube insertion?

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

Any pathogen cultured from lung tissue, when that lung tissue was obtained during an
open lung biopsy, video-assisted thoracoscopic surgery, or via other transthoracic or
transbronchial biopsy approach, may be reported with the exception of the excluded
pathogens belonging to the following genera: Blastomyces, Histoplasma, Coccidioides,
Paracoccidioides, Cryptococcus and Pneumocystis.
Any pathogen cultured from pleural fluid, when that fluid was obtained during
thoracentesis or at the time of initial chest tube insertion, may be reported with the
exception of the excluded pathogens belonging to the following genera: Blastomyces,
Histoplasma, Coccidioides, Paracoccidioides, Cryptococcus and Pneumocystis.

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19) How are “purulent respiratory secretions” defined?
 Purulent respiratory secretions used to meet Criterion #2 of the PVAP definition are
defined as:
o Secretions from the lungs, bronchi, or trachea with ≥ 25 neutrophils and ≤ 10
squamous epithelial cells per low power field [lpf, x100].
o If the laboratory reports semi-quantitative results, you should check with your
laboratory to be certain that the semi-quantitative results match the
quantitative thresholds noted above.
 If your laboratory is not able to provide additional information on how a semiquantitative reporting system corresponds to quantitative reporting ranges for neutrophils
and squamous epithelial cells, here is some guidance from the Clinical Microbiology
Procedures Handbook (3rd ed., 2010)*:
1+ = occasional or rare = <1 cell per low power field [lpf, x100]
2+ = few = 1-9 cells per low power field [lpf, x100]
3+ = moderate = 10-25 cells per low power field [lpf, x100]
4+ = heavy = >25 cells per low power field [lpf, x100]
o With this range in mind, and in the absence of additional information from your
laboratory, “purulent respiratory secretions” are defined as secretions that
contain heavy, 4+ or ≥25 neutrophils per low power field [lpf, x100]AND rare,
occasional, few, 1+ or 2+, or ≤10 squamous epithelial cells per low power field
[lpf, x100].
*Reference: Garcia, LS (Ed.). (2010). Clinical Microbiology Procedures Handbook. Herndon, VA:
ASM Press, page 3.2.1.16.



If your laboratory uses a different reporting format for results of direct examination of
respiratory secretions, you may still be able to use the purulent respiratory secretions
in meeting the PVAP definitions. See the instructions available in the VAE Protocol,
Table 2.

20) What is the definition of “positive lung histopathology” that can be used to meet the PVAP
definition?
 If the lung tissue specimen was obtained via open lung biopsy, video-assisted
thoracoscopic surgery, or via other transthoracic or transbronchial biopsy approach, it is
eligible for consideration in meeting the PVAP definition (Criterion 3).
 Histopathological findings that can be used to meet the PVAP definitions include:
o Abscess formation or foci of consolidation with intense neutrophil
accumulation in bronchioles and alveoli;
o Evidence of lung parenchyma invasion by fungi (hyphae, pseudohyphae or
yeast forms);
o Evidence of infection with the viral pathogens listed in FAQ no. 14 based on
results of immunohistochemical assays, cytology, or microscopy performed
on lung tissue.
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21) I am still having trouble understanding the time frame that defines a VAE. Can you explain
what is meant by this statement that appears in the algorithm: “On or after calendar day 3 of
mechanical ventilation and within 2 calendar days before or after the onset of worsening
oxygenation”?
 The intent of these criteria is to determine whether a VAC is due to an infectious process
(IVAC) and/or pneumonia (PVAP) by looking for corroborating inflammatory and
infectious signs at the time of VAC onset. The criterion, “on or after calendar day 3” is
intended to exclude inflammatory and infectious signs present on the first two days of
mechanical ventilation because they are more likely to be due to pre-existing conditions
than ventilator-acquired complications. The criterion, “within 2 calendar days before or
after the onset of worsening oxygenation,” is intended to identify infectious and
inflammatory signs that arise at the same time as VAC and may therefore point to the
cause of the VAC.


The figures below illustrate the time frame that defines a VAE. The event date is the first
day of worsening oxygenation, defined by the PEEP and FiO2 thresholds outlined in the
algorithm. The event date defines the time frame within which all other criteria must be
met. In the examples below, the shaded area defines the VAE Window Period in which
IVAC criteria (temperature or white count abnormalities, plus a new antimicrobial agent
started and continued for at least 4 days) must be met, and in which a PVAP criteriion
must be met.
NOTE: Keep in mind that VAE criteria must be met based on specimens collected or
antimicrobial agents started after day 2 of mechanical ventilation.
EXAMPLE 1: When the onset date of the VAE occurs early in the course of mechanical
ventilation (e.g., day 3 or 4 of mechanical ventilation), the period in which certain
inflammatory and infectious criteria are sought for IVAC and PVAP is shorter, because
the first 2 days of mechanical ventilation are excluded from the normal 5 day window
surrounding the day of increased ventilator support.

MV Day No.
Worsening oxygenation

Temperature abnormality or
white blood cell count
abnormality
Antimicrobial agent
Purulent respiratory secretions,
positive culture, positive
histopathology

January 2015

1
--

2
Day 1 of
Stability or
improvement

3
4
5
6
Day 2 of
Day 1 of
Day 2 of
stability or
worsening
worsening
improvement
oxygenation
oxygenation
An abnormal temperature or white blood cell count, according to
the algorithm parameters, must be documented within this shaded
period
New agent must be started on any day within this shaded period,
and then continued for at least 4 days
Specimen must be collected on any day within this shaded
period

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EXAMPLE 2: When the onset date of the VAE occurs later in the course of mechanical
ventilation, the period in which certain criteria must be met is a day longer, because the
patient has already been on mechanical ventilation for more than 3 days and therefore
inflammatory and infectious signs arising anywhere in the full 5-day window surrounding
the day of increased ventilator settings can count towards IVAC and PVAP.
MV Day No.
Worsening oxygenation

Temperature abnormality or
white blood cell count
abnormality
Antimicrobial agent
Purulent respiratory secretions,
positive culture, positive
histopathology

10
--

11
Day 1 of
Stability or
improvement

12
Day 2 of
stability or
improvement

13
Day 1 of
worsening
oxygenation

14
Day 2 of
worsening
oxygenation

An abnormal temperature or white blood cell count, according to the algorithm
parameters, must be documented within this shaded period
New agent must be started on any day within this shaded period, and then continued
for at least 4 days
Specimen must be collected on any day within this shaded period

22) Providers in my ICU use different types of mechanical ventilation for different patients. Can
you explain the circumstances in which mechanically-ventilated patients are to be excluded
from VAE surveillance, and the circumstances in which mechanically-ventilated patients
should be included in VAE surveillance?
 VAE surveillance is restricted to adult inpatient locations. Patients on mechanical
ventilation who are in adult inpatient locations in acute care and long-term acute care
hospitals and inpatient rehabilitation facilities are eligible for inclusion in VAE
surveillance.
 Patients are excluded from VAE surveillance during periods of time when they are
receiving high frequency ventilation, or if they are receiving extracorporeal life support
(extracorporeal membrane oxygenation).
 Patients are included in surveillance if they are on a ventilator (as defined in the VAE
surveillance protocol), and are being mechanically ventilated through an endotracheal or
tracheostomy tube using a conventional mode of mechanical ventilation (such as volume
controlled, pressure controlled, or pressure support mechanical ventilation).
o Patients on conventional mechanical ventilation who are receiving nitric
oxide, helium-oxygen mixtures (heliox) or epoprostenol therapy are included
in surveillance.
o Patients on conventional mechanical ventilation who are being ventilated in
the prone position are included in surveillance.
 Patients are also included in surveillance if they are on a ventilator (as defined in the
VAE surveillance protocol), and are being mechanically ventilated through an
endotracheal or tracheostomy tube using Airway Pressure Release Ventilation (APRV) or
related modes. Some terms that are used to indicate APRV or a related mode of
mechanical ventilation include (but may not be limited to): BiLevel, Bi Vent, BiPhasic,
PCV+, and DuoPAP.
o For patients on APRV or related modes, the period of worsening oxygenation
following a period of stability or improvement on the ventilator that is
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

required for identification of a VAE will be defined by the FiO2 criterion
within the VAE surveillance definition algorithm. The PEEP criterion may not
be applicable in patients on APRV or related modes of mechanical ventilation.
If you have questions about mechanical ventilation, you should check with the
Respiratory Care or Respiratory Therapy and/or Critical Care departments in your
facility.

23) Why do I need to indicate if a patient was on APRV at the time of VAE onset, and why do I
need to indicate the number of patients on APRV in my ICU for each day of VAE
surveillance?
 We are trying to find out more about how frequently APRV and related modes of
mechanical ventilation are being used, and the frequency with which VAEs are identified
in patients on APRV and related modes, to determine whether the VAE surveillance
definition algorithm may need to be modified in the future.
 If the VAE occurred in a patient on Airway Pressure Release Ventilation (APRV) or a
related mode of mechanical ventilation (e.g., BiLevel, Bi Vent, BiPhasic, PCV+,
DuoPAP) at the time of VAE onset, indicate “Yes” in the “APRV” field on the VAE
Form (CDC 57.112). Otherwise, indicate “No.”
 On the appropriate denominator form (CDC 57.117 or 57.118), in the column for
“Number of patients on a ventilator,” you will see that there are two sub-columns. In the
sub-column, “Total patients,” enter the total number of patients on a ventilator on that
day. In the sub-column, “Number on APRV,” enter the number for the subset of patients
on a ventilator on that day who are on the APRV mode of mechanical ventilation or
related modes (e.g., BiLevel, Bi Vent, BiPhasic, PCV+, DuoPAP) at the time the count is
performed. If there are no patients on APRV or a related mode of mechanical ventilation,
enter “0” (zero).
24) My laboratory only performs semi-quantitative cultures of lower respiratory tract specimens,
and cannot provide me with additional guidance to help me know what semi-quantitative
culture result corresponds to the quantitative thresholds specified in Criterion1 of the PVAP
definition. Can you provide more information?
 For the purposes of this surveillance, and in the absence of additional information
available from your laboratory, a semi-quantitative result of “moderate” or “heavy”
growth, or 2+, 3+ or 4+ growth, meets the PVAP definition (Criterion 1).

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Instructions for Completion of Ventilator-Associated Event Form
Data Field
Facility ID #
Event #
Patient ID #
Social Security #
Secondary ID #
Medicare #
Patient Name
Gender
Date of Birth
Ethnicity
Hispanic or Latino
Not Hispanic or Not
Latino
Race
Event Type
Date of Event

Post-procedure VAE
Date of Procedure
NHSN Procedure Code

ICD-9-CM Procedure Code

January 2015

Instructions for Data Collection
The NHSN-assigned facility ID will be auto-entered by the computer.
Event ID number will be auto-entered by the computer.
Required. Enter the alphanumeric patient ID number. This is the
patient identifier assigned by the hospital and may consist of any
combination of numbers and/or letters.
Optional. Enter the 9-digit numeric patient Social Security Number.
Optional. Enter the alphanumeric ID number assigned by the facility.
Optional. Enter the patient’s Medicare number.
Optional. Enter the last, first, and middle name of the patient.
Required. Check Female, Male, or Other to indicate the gender of the
patient.
Required. Record the date of the patient birth using this format:
MM/DD/YYYY.
Optional.
If patient is Hispanic or Latino, check this box.
If patient is not Hispanic or not Latino, check this box.
Optional.
Check all the boxes that apply to identify the patient’s race.
Required. VAE.
Required. The date of onset of worsening oxygenation (i.e., day 1 of
the ≥ 2-day period of worsening oxygenation, according to the VAE
PEEP or FiO2 criterion). Enter date using this format:
MM/DD/YYYY.
Optional. Check Y if this event occurred after an NHSN-defined
procedure but before discharge from the facility; otherwise, check N.
Conditionally required. If Post-procedure VAE = Y, then enter the
date the procedure was done.
Conditionally required. Answer this question only if this patient
developed the VAE during the same admission as an operative
procedure. Enter the appropriate NHSN procedure code.
NOTE: A VAE cannot be “linked” to an operative procedure unless
that procedure has already been added to NHSN. If the procedure was
previously added, and the “Link to Procedure” button is clicked, the
fields pertaining to the operation will be auto-entered by the
computer.
Optional. The ICD-9-CM code may be entered here instead of (or in
addition to) the NHSN Procedure Code. If the ICD-9-CM code is
entered, the NHSN code will be auto-entered by the computer. If the
NHSN code is entered first, you will have the option to select the
appropriate ICD-9-CM code. In either case, it is optional to select the
ICD-9-CM code. Only those ICD-9-CM codes identified in Table 1

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Data Field

MDRO Infection
Surveillance

Date Admitted to Facility

Location

Risk Factors: Location of
Intubation or Mechanical
Ventilation Initiation

Risk Factors: Date Initiated

January 2015

Instructions for Data Collection
of the Surgical Site Infection Event Chapter (Chapter 9 of NHSN
Manual: Patient Safety Component Protocol) are allowed.
Required. Check Y if the event is a Possible or Probable VAP AND if
one of the following pathogens is reported AND if the pathogen is
being followed for Infection Surveillance in the MDRO/CDI Module
in that location as part of your Monthly Reporting Plan: MRSA,
MSSA (MRSA/MSSA), VRE, CephR-Klebsiella, CRE-E. coli, CREEnterobacter ,CRE-Klebsiella, MDR-Acinetobacter. If the pathogen
for Possible or Probable VAP happens to be an MDRO but your
facility is not following the Infection Surveillance in the MDRO/CDI
Module in your Monthly Reporting Plan, check N for this question.
Check N if the VAE specific event is VAC or IVAC, since pathogens
cannot be reported for these events.
Required. Enter date patient admitted to facility using this format:
MM/DD/YYYY. An NHSN Inpatient is defined as a patient whose
date of admission to the healthcare facility and the date of discharge
are different calendar days. When determining a patient’s admission
dates to both the facility and specific inpatient location, the NHSN
user must take into account all such days, including any days spent in
an inpatient location as an “observation” patient before being
officially admitted as an inpatient to the facility, as these days
contribute to exposure risk. Therefore, all such days are included in
the counts of admissions and patient days for the facility and specific
location, and facility and admission dates must be moved back to the
first day spent in the inpatient location.
Required. Enter the inpatient location to which the patient was
assigned when the VAE was identified (i.e., day 1 of the ≥ 2-day
period of worsening oxygenation). If the VAE develops in a patient
within 2 days of transfer from a location (where the day of transfer is
day 1), indicate the transferring location, not the current location of
the patient.
Required. Enter the location in which the current episode of
mechanical ventilation was initiated (the episode associated with the
VAE). Location of intubation or location of mechanical ventilation
initiation for patients with a tracheostomy. If this episode of
mechanical ventilation was initiated in another facility or by mobile
emergency services, enter the code you have mapped to “Location
Outside Facility” ) or Mobile Emergency Services/EMS (see Chapter
15) as appropriate. An episode of mechanical ventilation is defined by
the number of consecutive days during which the patient was
mechanically ventilated. A period of at least 1calendar day off the
ventilator, followed by reintubation or re-initiation of mechanical
ventilation, defines a new episode of mechanical ventilation.
Required. Enter the date that the current episode of mechanical
ventilation was initiated (the episode associated with the VAE). Use
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Data Field

Risk Factors: APRV

Event Details: VAE
Specific Event
Event Details:
Specify Criteria Used
Event Details: Secondary
Bloodstream Infection
Event Details:
Died
Event Details:
VAE Contributed to Death
Event Details:
Discharge Date
Event Details:
Pathogen Identified

Instructions for Data Collection
this format: MM/DD/YYYY. An episode of mechanical ventilation is
defined by the number of consecutive days during which the patient
was mechanically ventilated. A period of at least 1 calendar day off
the ventilator, followed by reintubation, defines a new episode of
mechanical ventilation.
Required. Check Yes if this event occurred in a patient on Airway
Pressure Release Ventilation (APRV) or a related mode of
mechanical ventilation (e.g., BiLevel, Bi Vent, BiPhasic, PCV+,
DuoPAP) at the time of VAE onset; otherwise, check No. NOTE:
VAEs in patients on APRV should be detected and reported using the
FiO2 criterion; the PEEP criterion is not applicable to patients on
APRV.
Required. Check one: Ventilator-Associated Condition (VAC),
Infection-related Ventilator-Associated Complication (IVAC),
Possible Ventilator-Associated Pneumonia (PVAP)
Required. Check each of the elements that were used to identify this
VAE.
Required. Check Y if there is a culture-confirmed bloodstream
infection (BSI) and a related PVAP, otherwise check N. Note that
secondary BSI must be checked N if the event is a VAC or IVAC.
Required. Check Y if patient died during the hospitalization,
otherwise check N.
Conditionally required. If the patient died, check Y if the VAE
contributed to death, otherwise check N.
Optional. Date patient discharged from facility.
Required. This field will be auto entered by the computer as N for
VAC and IVAC (for which pathogens cannot be reported). Specify
pathogens on reverse form.
For specified Gram-positive organisms, Gram-negative organisms, or
other organisms, Pathogen #:
Up to three pathogens may be reported. If multiple pathogens are
identified, enter the pathogen judged to be the most important cause
of infection as #1, the next most as #2, and the least as #3 (usually
this order will be indicated on the laboratory report). If the species is
not given on the lab report or is not found on the NHSN drop down
list, then select the “spp” choice for the genus (e.g., Bacillus cohnii
would be reported as Bacillus spp.).
Antimicrobial agent and susceptibility results:
Conditionally required if Pathogen Identified = Y.
• For those organisms shown on the back of an event form,

January 2015

10-49

Device-associated Module
VAE

Data Field

Instructions for Data Collection
susceptibility results are required only for the agents listed.
• For organisms that are not listed on the back of an event form,
enter a susceptibility result for at least one antimicrobial agent,
even if that result is “Not Tested”.
Circle the pathogen’s susceptibility result using the codes on the
event forms.
Additional antimicrobial agents and susceptibility results may be
reported for up to a total of 20 agents.

Custom Fields

Comments

January 2015

Optional. Up to 50 fields may be customized for local or group use in
any combination of the following formats: date (MMDDYYY),
numeric, or alphanumeric.
NOTE: Each Custom Field must be set up in the Facility/Custom
Options section of the application before the field can be selected for
use.
Optional. Enter any information on the event.

10-50

File Type	application/pdf
File Title	6 Ventilator-associated Pneumonia (VAP) Events
Subject	Information on Ventilator-associated pneumonia events
Author	CDC User
File Modified	2014-06-03
File Created	2014-06-03