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NHSN Dialysis Event Manual
Dialysis Event Protocol

Dialysis Event Protocol
Introduction
In 2010, more than 380,000 patients were treated with maintenance hemodialysis in the
United States. 13 Hemodialysis patients require a vascular access, which can be a catheter or
a graft or an enlarged blood vessel that can be punctured to remove and replace blood.
Bloodstream infections and localized infections of the vascular access site cause substantial
morbidity and mortality in hemodialysis patients. Hemodialysis vascular access types, in
order of increasing risk of infection, include arteriovenous fistulas created from the
patient’s own blood vessels; arteriovenous grafts typically constructed from synthetic
materials; tunneled central lines; and nontunneled central lines. Other access devices, such
as catheter-graft hybrid devices, also exist. Because of frequent hospitalizations and receipt
of antimicrobial drugs, hemodialysis patients are also at high risk for infection with
antimicrobial-resistant bacteria. Measuring and tracking rates of infection and utilizing this
information is an important part of prevention.
Infection prevention information is located at http://www.cdc.gov/dialysis/
Dialysis Event Surveillance
Overview: Each month, facilities report the number of maintenance hemodialysis
outpatients who were dialyzed in the facility on the first two working days of the month,
using the Denominators for Outpatient Dialysis form. This count is used to estimate the
number of patients at the facility who are at risk of healthcare-associated infection.
Throughout the entire month, any and all outpatients who receive maintenance
hemodialysis at the facility are monitored for three NHSN-defined dialysis events, which
include IV antimicrobial starts, positive blood cultures, and evidence of local access site
infection. Each month, facilities use a Dialysis Event form to report the details of each
dialysis event that occurred among these patients. Before data can be reported, facilities
must indicate that they are reporting according to protocol by saving a Patient Safety
Monthly Reporting Plan. Completion of an Outpatient Dialysis Center Practices Survey is
required annually.
Setting: Surveillance occurs in outpatient hemodialysis centers. These centers may be
attached to or affiliated with a hospital, but should serve hemodialysis outpatients. If
other patients (e.g., inpatients, peritoneal dialysis patients) are present in this setting,
exclude them from Dialysis Event reporting.

U.S. Renal Data System, USRDS 2012 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage
Renal Disease in the United States, National Institutes of Health, National Institute of Diabetes and Digestive
and Kidney Diseases, Bethesda, MD, 2011. (http://www.usrds.org/adr.htm)
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Population: Maintenance hemodialysis outpatients.

Requirements: Participating facilities are required to report data according to this
protocol, using the NHSN definitions described herein, to ensure data are uniformly
reported across participating facilities. A minimum of 6 months of Dialysis Event (DE)
surveillance at an outpatient hemodialysis facility, indicated on the Patient Safety Monthly
Reporting Plan (CDC 57.106), is required by CDC 14. Data must be reported to NHSN within
30 days of the end of the month for which they were collected (e.g., patient census
information from September must be reported no later than October 30).
Definitions of Dialysis Events
Dialysis Event: Three types of dialysis events are reported by users: IV antimicrobial start;
positive blood culture; and pus, redness, or increased swelling at the vascular access site.
An additional four types of dialysis events are generated from the reported data:
bloodstream infection (BSI), local access site infection (LASI), access-related bloodstream
infection (ARB), and vascular access infection (VAI). The numbers of the different dialysis
event types are used as the numerator for the calculation of dialysis event rates.

IV antimicrobial start: Report all occurrences where intravenous (IV) antibiotics or
antifungals are administered in an outpatient setting, regardless of the reason for
administration (i.e., include IV antimicrobial starts unrelated to vascular access problems)
and regardless of the duration of treatment. Report all IV antibiotic administrations, not
just vancomycin. Do not report IV antiviral starts. Report outpatient starts that are
continuations of inpatient treatment.
•

21 day rule: There must be 21 or more days from the end of the first IV
antimicrobial course that was started in an outpatient setting to the beginning of a
second IV antimicrobial start in an outpatient setting for two starts to be reported as
separate dialysis events, even if different antimicrobials are used. If IV
antimicrobials are stopped for less than 21 days and then restarted, the second start
is NOT considered a new dialysis event and therefore, not reported. For outpatient
IV antimicrobial starts that are continuations of inpatient treatment, consider the
start day to be the first day of outpatient administration.

Positive blood culture: Report all positive blood cultures from specimens collected as an
outpatient or collected within one calendar day after a hospital admission, regardless of
whether or not the patient received treatment. The date of a blood culture result is based
14

Other organizations (e.g., your ESRD Network or State Health Department) may require additional months of
reporting. Participants reporting to meet the Centers for Medicare and Medicaid (CMS) End Stage Renal Disease
(ESRD) Quality Incentive Program (QIP) rule requirements may report as few as three consecutive months of data
in 2012.
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Dialysis Event Protocol

on the date the blood specimen was collected, not the date the laboratory reported the
result.
•

21 day rule: There must be 21 or more days between positive blood cultures for
each positive blood culture to be considered a separate dialysis event, even if
organisms are different. If positive blood cultures occur less than 21 days apart, the
second positive blood culture(s) is NOT considered a new dialysis event and
therefore, is not reported. However, if different organisms grow from these
subsequent positive blood cultures, add the new organisms to the first report.

Pus, redness, or increased swelling at the vascular access site: Report each new outpatient
episode where the patient has one or more symptoms of pus, greater than expected
redness or greater than expected swelling at any vascular access site, regardless of whether
the patient received treatment.
•

21 day rule: There must be 21 or more days between the onset of a first episode and
the onset of a second episode of pus, redness, or increased swelling at a vascular
access site to be considered separate dialysis events. If an episode of pus, redness, or
increased swelling at a vascular access site resolves and then recurs within 21 days
of the first onset, the recurrence is NOT considered a new dialysis event and
therefore, is not reported.

Bloodstream infection (BSI): Any positive blood culture.

Access-related bloodstream infection (ARB): Positive blood culture with the suspected
source reported as the vascular access or uncertain.

Local access site infection (LASI): Pus, redness, or swelling of the vascular access site and
access-related bloodstream infection is not present.
Vascular access infection (VAI): Either a local access site infection or an access-related
bloodstream infection.

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Vascular Access Types
Include all vascular accesses in Dialysis Event reporting, even if they are not used for
dialysis and even if they are abandoned and/or are non-functional.
•

•

•

•
•

Nontunneled central line: a central venous catheter that travels directly from the
skin entry site to a vein and terminates close to the heart or one of the great vessels,
typically intended for short term use.
Tunneled central line: a central venous catheter that travels a distance under the
skin from the point of insertion before terminating at or close to the heart or one of
the great vessels (e.g., Hickman® or Broviac® catheters 15).

Graft: a surgically created connection between an artery and a vein using implanted
material (typically synthetic tubing) to provide a permanent vascular access for
hemodialysis.

Fistula: a surgically created direct connection between an artery and a vein to
provide vascular access for hemodialysis.
Other access device: includes hybrid access devices (e.g., HeRO® vascular access
device15), ports, and any other central vascular access devices that do not meet the
above definitions.

REPORTING INSTRUCTIONS
NHSN forms should be used to collect required data, using the definitions outlined in
this protocol. Each form has a corresponding table of instructions.

Complete a Survey Annually: Upon enrollment and annually thereafter, complete the
Outpatient Dialysis Center Practices Survey (CDC 57.104). After enrollment, the data for the
dialysis survey should be collected in January, but are due in NHSN by April 1 each year.

Patient Safety Monthly Reporting Plan: The Patient Safety Monthly Reporting Plan (CDC
57.106) is used by NHSN facilities to inform CDC which Patient Safety modules are used
during a given month. There must be a Monthly Reporting Plan completed before data are
entered into NHSN for that month. To indicate the facility is reporting as defined by this
protocol, save a Monthly Reporting Plan with “DE” selected for the ‘outpatient hemodialysis
clinic’ location, under the Device-Associated section for each month that they will be doing
Dialysis Event surveillance.
Use of trade names and commercial sources is for identification only and does not imply endorsement.
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Report Denominator Data Monthly: Each month, report the number of maintenance
hemodialysis outpatients with each vascular access type who received hemodialysis at
the center during the first two working days of the month on the Denominators for
Outpatient Dialysis form (CDC 57.119). Report all maintenance hemodialysis
outpatients, including transient patients. Exclude non-hemodialysis patients and
exclude inpatients. Report denominator data each month, regardless of whether any
dialysis events occur. Count each patient only once; if the patient has multiple vascular
accesses, record that patient once, reporting only their vascular access with the highest
risk of infection. See tables of instructions for an explanation of each field of the
Denominators for Outpatient Dialysis form.
HIGHER
RISK

Nontunneled
Central
Lines

Tunneled
Central
Lines

Other
Access
Devices

AV
Grafts

AV
Fistulas

LOWER
RISK

Report Numerator Data Monthly: Each month, complete one Dialysis Event form (CDC
57.109) per occurrence of event(s) among all patients who received hemodialysis at the
facility during that month. Complete a Dialysis Event form only if a maintenance
hemodialysis outpatient has one or more of the following:
• IV antimicrobial start
• Positive blood culture
• Pus, redness or increased swelling at the vascular access site
See tables of instructions for an explanation of each field of the Dialysis Event form.
If a transient patient has a dialysis event during the time he or she is receiving
hemodialysis treatment at your facility, report the dialysis event. If no dialysis events
occurred during a given month, select ‘Report No Events’ on the Denominators for
Outpatient Dialysis form.

If multiple dialysis events occur together, as a part of the same patient problem, they
should be reported as one dialysis event. For example, if a patient has a positive blood
culture and begins IV antimicrobials, these two events would be recorded together on one
form. When reporting multiple dialysis events together, always use the date from the first
event that occurred. Refer to dialysis event definitions for the 21 day rule. Do not report
unrelated dialysis events on the same form.

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Suspected source of the positive blood culture: indicating one of four suspected sources of
a positive blood culture is required.
•

•

Vascular access: Choose “Vascular access” if there is objective evidence of
vascular access infection and the vascular access is thought to be the source
of the positive blood culture.

A source other than the vascular access: Choose “A source other than the
vascular access” if either (a) or (b) is true:
a) a culture from another site (e.g., infected leg wound, urine) shows the same
organism found in the blood and the site is thought to be the source of the
positive blood culture.
b) there is clinical evidence of infection at another site which is thought to be the
source of the positive blood culture, but the site was not sampled for culture.
•

•

Contamination: Choose “Contamination” if the organism isolated from the
blood culture is thought by the physician, infection preventionist, or nurse
manager to be a contaminant. Contamination is more likely if the organism is
a common commensal and is isolated from only one blood culture. Examples
of common commensals include: diphtheroids [Corynebacterium spp., not C.
diphtheriae]; Bacillus [not B. anthracis] spp.; Propionibacterium spp.;
coagulase-negative staphylococci [including S. epidermidis]; viridans group
streptococci; Aerococcus spp.; and Micrococcus spp.
Uncertain: Choose “Uncertain” only if there is insufficient evidence to decide among
the three previous suspected source categories.

Data Analyses: Dialysis event rates are stratified by vascular access type and expressed
per 100 patient-months. Rates are calculated by dividing the number of events by the
number of patient-months and multiplying the result by 100. CDC calculates pooled
mean rates for each event type by combining rates from all participating facilities.
Facilities can compare their rates with the pooled mean rates using NHSN analysis rate
table or run chart output options. Facilities are strongly encouraged to analyze the data
they report and provide regular feedback to staff about patient outcome event rates.
Reporting Resources

𝑟𝑎𝑡𝑒 =

𝐷𝑖𝑎𝑙𝑦𝑠𝑖𝑠 𝐸𝑣𝑒𝑛𝑡𝑠 (𝑛𝑢𝑚𝑒𝑟𝑎𝑡𝑜𝑟)
× 100
𝑃𝑎𝑡𝑖𝑒𝑛𝑡 𝐶𝑒𝑛𝑠𝑢𝑠 (𝑑𝑒𝑛𝑜𝑚𝑖𝑛𝑎𝑡𝑜𝑟)

Data collection and reporting resources are available on the NHSN Dialysis Event website:
http://www.cdc.gov/nhsn/dialysis/dialysis-event.html. Please direct questions to the NHSN
Helpdesk at [email protected].
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