Download Needlestick Injuries - Calgary Emergency Medicine

Needlestick
Injuries:
Medical Evidence and
Legal Issues
Emergency Medicine
Grand Rounds
Nov 29th, 2001
Ian Walker, CCFP(EM)
Objectives
Review the literature regarding
needlestick injuries
Determine how one accurately
assesses risk
Review the evidence for and current
recommendations regarding PEP
Review some legal issues and current
CRH policy re: source patient testing
Epidemiology
Actual seroconversion uncommon

94 confirmed cases worldwide prior to 1997
Exposure very common

Up to 52% of HCW report at least one prior
needlestick, and 24% report one in the past
year.
Risk depends on prevalence of HIV
Calgary wide ~ 0.5%
 Amongst needle users ~ 5%

Canadian Data
Canadian Needlestick Surveillance
Network – April 1 to Sept 30, 2000
599 exposures at 10 sites nationwide
209 at FMC
Overall, 1.8 exposures per 100 FTE
Nurses incurred ~56% of these
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High Risk Groups
16
14
12
10
8
6
4
2
0
Rates per
100 FTE's
Location of Exposures
Wards
27%
Other
30%
O&G / L&D
8%
Dialysis
4%
ICU
7%
Emerg
8%
OR
16%
Wards
O&G / L&D
OR
Emerg
ICU
Dialysis
Other
What is the Risk?
Generally quoted as 0.3% for
percutaneous exposures
Based on meta-analyses of multiple
small prospective series
Aggregated data from 23 studies
6202 exposures, 20 seroconversions
 0.32% conversion rate (CI 0.20%-0.50%)

Wide range of types of exposure
Muco-cutaneous Exposure
Skin and mucus membrane exposure
risk poorly quantified
Mucus membrane risk quoted as 0.09%
Based on a single case out of 1107
documented exposures
 ICU nurse manipulating an arterial catheter
in a hemophiliac patient – “hands, eyes,
mouth splashed with very large amounts of
blood”

Non-Intact Skin
Cases of seroconversion have been reported
following exposure to non-intact skin


Exact risk not quantified due to infrequency of
event
Estimated by the CDC to be less than that for
mucus membrane exposure
Infection following exposure to intact skin has
not been reported

2712 exposures with no seroconversion (95% CI 0
to 0.1%)
Risk Assessment
Related to two variables
1. The amount of blood to which the patient is
exposed
2. The amount of HIV in the exposed blood (i.e. the
viral load of the source patient)
Traditionally, “risk assessments” done for
patients of unknown HIV status



Increasingly unreliable
In 1985, 94% of all AIDS patients had a major RF
In 1996, 20% of all patients had been infected
through heterosexual contact or had no known RF
One Case-control Study
33 cases (seroconverted), 665 controls
Factors associated with increased risk of
HIV seroconversion
Deep injury (OR = 15)
 Visible blood on device (OR = 6.2)
 Procedure involving artery or vein (OR = 4.3)
 Terminal illness in source pt. (OR = 5.6)

Cardo, et al. “A Case-control Study of HIV Seroconversion in Health Care Workers after
Percutaneous Exposure” NEJM 337:21, pp. 1485-90. 1997
Non-Risks
Some factors surprising not associated
with increased risk.
Large bore needles
 Use of gloves
 Hollow bore vs. suture needles

Clinical Condition of the Source
In the NEJM study, advanced terminal
disease in the source pt associated with
increased risk.
Another study looked at source pt’s disease


Asymptomatic: 0 conversions out of 148
AIDS: 4 conversions out of 889
Reasonable to conclude that advanced
disease in the source is a risk factor
Loose Needles
What of cleaning staff who get a
percutaneous exposure of unknown
significance?
No data available
Risk assessment based on prevalence
of HIV amongst possible source pts
Risk generally regarded as very low
Post-Exposure Prophylaxis
Does it work?
Most data from animal studies
Many use Simian Immunodeficiency Virus
 Inoculums generally large
 Delay to drug administration varies

Indirect evidence from maternal – fetal
studies
Human Studies
Attempt to carry out an RCT unsuccessful


Only 84 patients enrolled over >1 year
New trial probably now unethical
The NEJM case-control study




Looked at AZT use
Cases less likely to have used AZT (OR 0.19,
p=0.003)
Hence the quoted 80% reduction (CI 43%-94%)
ARR = 0.24%, NNT = 417!!
Limitations of the Evidence
Animal studies represent poor models for
occupational human exposure
Retrospective studies subject to many biases
Perinatal exposure fundamentally different
from occupational exposure
AZT PEP has been documented ineffective in
at least 21 cases worldwide.
6 Cases of ineffective combination therapy
The “2 Hour Window”
Extrapolated from animal studies & our
understanding of HIV pathogenesis
Most studies done with primates, with
PEP given within 24 hrs being effective.
Efficacy decreases at 48hrs
Efficacy also decreased when regimen
shortened to 3 or 10 days
Bottom line – the sooner the better
Who Should Get PEP?
For needlesticks, can think in terms of
source factors and exposure factors:
Known HIV +’ve source
 Advanced disease in the source patient
 Visible blood on needle
 Needle from artery or vein
 Deep injury

A matter of multiplying risks
What Do I Give?
Studies all done with AZT alone for
prophylaxis (either peri-natal or occupational)
Addition of Lamivudine (3TC) generally
recommended


Concern re AZT resistance
Demonstrated superiority of combination therapy
in HIV +’ve patients
Addition of protease inhibitor (PI), i.e.
Indinavir or Nelfinavir in high risk cases
Early enthusiasm for Nevirapine (an NNRTI)
tempered by serious hepatic toxicity
Current CDC Guidelines
Evaluation
Test source patients for HBsAg, Anti-HCV,
and HIV antibody



Direct virus assays not recommended
Consider rapid HIV test
If source is negative, no further follow up
recommended (OH&S?)
Unknown or un-testable source

Assess risk of bloodborn pathogen in general
population or individual patient if known.
Current CDC Guidelines
Treatment
Recommended when source patient is HIV
+’ve or deemed likely to be
2 Drug PEP



Less severe exposures (see RF’s) to an
asymptomatic HIV +’ve source
Exposure to unknown source where HIV infection
likely
Exposure to source with unknown HIV status but
with RF’s (IVDU, etc…)
Current CDC Guidelines
Treatment, cont.
3 Drug PEP


More severe exposure to asymptomatic or
symptomatic HIV +’ve source
Less severe exposure to a symptomatic HIV +’ve
source (incl acute seroconversion)
With mucous membrane exposures, same
recommendations apply


“Large volume” is considered a severe exposure
“Small volume” (i.e.. a few drops) is less severe
When to Speak to ID
Pregnant or breast feeding patients
Source patient already on retrovirals
Delayed exposure
Significant renal or hepatic disease
Unknown source
CHR OH&S Policy
Patients referred to ED if source known
positive or high risk
Surveillance only if low or unknown risk
Routine exposures treated with
AZT/3TC
More significant exposures get the
addition of Nelfinavir (Viracept™)
Rapid POC Testing
Rapid HIV testing now widely available,
inexpensive and reliable
Blinded study comparing to non-rapid assays
and Western blot yielded a sensitivity of
100% and a specificity of 99.1% (7 false
positives out of 837)
One ED based study evaluated two rapid
assays in 495 consecutive patients


Correctly identified all 25 positives
One false positive, No false negatives
Rapid Testing In Calgary
CLS uses an assay which is equivalent to the
“Determine” Assay by Abbott
Sensitivity and Specificity both 99.9%
Done in the on-site rapid response labs
Current turn around time 1 hr 24 min
Confirmed by Western Blot at Prov Lab
Reagent costs ~$7 per test

Majority of costs due to “STAT” processing
Can be done as an “add-on” to serum sample
Compliance Issues
Two or three drug regimens generally well
tolerated
More side effects attributable to PI than to
AZT / 3TC
Serious adverse events few
Given high NNT, concerns raised over NNH
2 Cases of fulminant hepatic failure with
Nevirapine
The HIV PEP Registry
Conducted 1996-1999 by the CDC
Voluntarily enrolled 492 potential HIV
exposed HCW’s who received PEP
Followed to 6 weeks
Monitored for regimen, compliance,
common and serious adverse events
Not a controlled study
PEP Regimes
17 different regimes
used
Most commonly




AZT & 3TC (36%)
AZT, 3TC & Indinavir
(45%)
AZT, 3TC &
Saquinovir (5%)
AZT, 3TC &
Nelfinavir (3%)
Combivir
Combivir + IDV
Combivir + SQV
Combivir + NFV
Other
Compliance
449 patients with FU
data
47% completed PEP
9% discontinued
one drug
44% discontinued all
drugs


50% due to
symptoms
48% source pt tested
negative
Complete
D/C one drug
D/C due to SE
D/C due to Neg Test
Adverse Events - Common
Most common: nausea (57%)
Vomiting & Diarrhea (14% & 16%)
Headache (18%)
Fatigue or Malaise (38%)
Mean time to onset of symptoms 3 or 4
days for all of the above
Not able to determine what proportion
attributable to PI’s as opposed to others
Adverse Events - Serious
Defined as life threatening, permanent or
requiring hospitalization
6 cases


1 case of fever and rash on 5 drug regime
2 cases of renal colic on AZT/3TC/IDV


2 cases of severe N&V on AZT/3TC/SQV


1 on day 3, 1 on day 23
Occurred on days 3&4
1 case of bizarre episodic eye movements and
blurred vision which occurred on day 2
Legal Issues
A large part of making an appropriate
assessment is determining the HIV
status of the source patient.
What if the patient won’t, or can’t
consent?
Issue of testing unconscious,
incompetent or dead patients becoming
increasingly prominent.
Current Alberta Legal Status
Issue governed by common law
States that any medical intervention must be
consented to (otherwise it is assault)
 In emergency situations, can assume
consent for procedures that are therapeutic.
 Surrogate consent has no legal standing
 Other provinces (i.e. Ontario) have legislation
which legitimizes surrogate consent for nontherapeutic procedures.

The Arguments
Patient’s right to privacy
Positive test has implications for work,
housing, mental health, interpersonal
relationships, insurance, etc…
Patient may not want to know
If tested, then we have an obligation to
inform patient of a positive result.
The Counter Arguments
Information has implications for the health
care worker


Anxiety
Potentially unnecessary exposure to toxic drugs
Risk of exposure can be minimized, but not
avoided
In event of seroconversion, still have
obligation to inform source patient, so
needlestick recipient becomes a “surrogate
test”
Current MAB Policy
Newly approved blanket consent form
for new admissions
Authorizes testing in the case of exposure
 Does not cover patients admitted
emergently through ER, trauma pts, etc…
 Legally uncertain but deemed “defensible”

Still no recognition of surrogate consent

MAB limited by lack of legal standing
What Can You Do?
Hon David Hancock
Attorney General of
Alberta
#208, 10800 - 97 Avenue
Edmonton, AB
T5K 2B6
Phone: (780) 427-2339
Fax: (780) 422-6621
Hon Gary Mar
Minister of Health &
Wellness
#323, 10800 - 97 Avenue
Edmonton, AB
T5K 2B6
Phone: (780) 427-3665
Fax: (780) 415-0961
Take Home Message
PEP likely effective in decreasing rate of
seroconversion after significant HIV
exposures
Risk assessment includes
Status or degree of risk of source
 Depth of injury
 Presence of visible blood
 Procedure involving artery or vein

Take Home Message
Rapid HIV testing helpful and reliable
One or two doses of PEP usually well
tolerated
Average risk patients – Combivir
High risk patients – Combivir & Nelfinavir
Involve OH&S
Write to your MLA if concerned about the
legality of testing source patients