Needlestick Injuries:

Medical Evidence and Legal Issues

Emergency Medicine Grand Rounds

Nov 29th, 2001

Ian Walker, CCFP(EM)

ObjectivesReview the literature regarding needlestick injuriesDetermine how one accurately assesses riskReview the evidence for and current recommendations regarding PEPReview some legal issues and current CRH policy re: source patient testing

Epidemiology

Actual seroconversion uncommon94 confirmed cases worldwide prior to 1997

Exposure very commonUp to 52% of HCW report at least one prior

needlestick, and 24% report one in the past year.

Risk depends on prevalence of HIVCalgary 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

High Risk Groups

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Rates per100 FTE's

Location of Exposures

Wards27%

O&G / L&D8%

OR16%

ICU7%

Dialysis4%

Other30%

Emerg8%

Wards

O&G / L&D

OR

Emerg

ICU

Dialysis

Other

What is the Risk?

Generally quoted as 0.3% for percutaneous exposuresBased on meta-analyses of multiple small prospective seriesAggregated data from 23 studies6202 exposures, 20 seroconversions0.32% conversion rate (CI 0.20%-0.50%)

Wide range of types of exposure

Muco-cutaneous Exposure

Skin and mucus membrane exposure risk poorly quantifiedMucus 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 variables1. The amount of blood to which the patient is

exposed2. 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 seroconversionDeep 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 needlesUse of glovesHollow 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 studiesMany use Simian Immunodeficiency Virus Inoculums generally largeDelay 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 pathogenesisMost studies done with primates, with PEP given within 24 hrs being effective. Efficacy decreases at 48hrsEfficacy also decreased when regimen shortened to 3 or 10 daysBottom line – the sooner the better

Who Should Get PEP?

For needlesticks, can think in terms of source factors and exposure factors:Known HIV +’ve sourceAdvanced disease in the source patientVisible blood on needleNeedle from artery or veinDeep 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 casesEarly enthusiasm for Nevirapine (an NNRTI) tempered by serious hepatic toxicity

Current CDC Guidelines

EvaluationTest 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

TreatmentRecommended when source patient is HIV +’ve or deemed likely to be2 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 reliableBlinded 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 AbbottSensitivity and Specificity both 99.9%Done in the on-site rapid response labsCurrent turn around time 1 hr 24 minConfirmed by Western Blot at Prov LabReagent 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 usedMost commonly AZT & 3TC (36%) AZT, 3TC & Indinavir

(45%) AZT, 3TC &

Saquinovir (5%) AZT, 3TC &

Nelfinavir (3%)CombivirCombivir + IDVCombivir + SQVCombivir + NFVOther

Compliance

449 patients with FU data47% completed PEP9% discontinued one drug44% discontinued all drugs 50% due to

symptoms 48% source pt tested

negative

CompleteD/C one drugD/C due to SED/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 aboveNot 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

1 on day 3, 1 on day 23

2 cases of severe N&V on AZT/3TC/SQV 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 standingOther provinces (i.e. Ontario) have legislation

which legitimizes surrogate consent for non-therapeutic 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 avoidedIn 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 admissionsAuthorizes testing in the case of exposureDoes not cover patients admitted

emergently through ER, trauma pts, etc…Legally uncertain but deemed “defensible”

Still no recognition of surrogate consentMAB 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 exposuresRisk assessment includesStatus or degree of risk of sourceDepth of injuryPresence of visible bloodProcedure involving artery or vein

Take Home Message

Rapid HIV testing helpful and reliableOne or two doses of PEP usually well toleratedAverage risk patients – CombivirHigh risk patients – Combivir & NelfinavirInvolve OH&SWrite to your MLA if concerned about the legality of testing source patients