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Current Issues Regarding Disinfection & Sterilization of Prion Contaminated Medical Instruments. Jeannie Druckenmiller Wisconsin Division of Public Health 2011. Incident: 2009. Patient with rapidly progressive dementia

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current issues regarding disinfection sterilization of prion contaminated medical instruments

Current Issues Regarding Disinfection & Sterilization of Prion Contaminated Medical Instruments

Jeannie Druckenmiller

Wisconsin Division of Public Health

2011

incident 2009
Incident: 2009
  • Patient with rapidly progressive dementia
  • Tumor found, bx done – not malignant; no histology indicating prion disease
  • Pt mental status continues to rapidly deteriorate
  • CJD discovered at full brain autopsy
  • Bx instruments used on > 50 other patients
incident 2009 cont
Incident: 2009 cont.
  • Per hospital policy, the biopsy on the tumor was considered to be neuro-surgery on a ‘space-occupying lesion’, hence Infection Prevention was not notified in advance
2010 shea guideline to disinfection and sterization of prion contaminated medical instruments
2010 SHEA Guideline to Disinfection and Sterization of Prion-Contaminated Medical Instruments
  • Rutala WA, Weber DJ. Guideline for disinfection and sterilization of Prion-Contaminated Medical Instruments. Infect Control Hosp Epidemiol 2010;31:107-117.
  • http://www.unc.edu/depts/spice/dis/ICHE-2010-Feb-p107.pdf
  • Letter from CDC, Belay et al, Dec 2010
  • Reply from Rutala to Belay letter
2010 shea guideline cont background
2010 SHEA Guideline cont.Background
  • Iatrogenic transmission of CJD described in humans in only 3 circumstances:
    • Intracranial electrodes/neuro surgery
    • Cadaveric growth hormone therapy
    • Contaminated grafts from human tissue (dura matter >190 cases) processed prior to 1987 and corneas (2 cases)

Rutala and Weber, 2010

2010 shea guideline cont background6
2010 SHEA Guideline cont.Background
  • Summary: All known instances resulted from exposure to infected brain, pituitary or posterior eye tissue.

Rutala and Weber, 2010

2010 shea guideline cont background7
2010 SHEA Guideline cont.Background
  • No known cases transmitted by contaminated medical instruments in past several decades (>30 yrs)
  • Transmission is inefficient and current cleaning and disinfection methods, “though suboptimal may be preventing disease.”
2010 shea guideline cont background8
2010 SHEA Guideline cont.Background
  • Studies of iatrogenic-associated CJD from 1952-1976 are missing important details regarding methodology of reprocessing.
  • No known cases attributable to reuse of devices or associated with transfusion of blood products.
2010 shea guideline cont background9
2010 SHEA Guideline cont. Background
  • Prions exhibit extreme resistance to conventional methods of disinfection / sterilization
  • Past studies have NOT detailed the reprocessing procedures
  • 1) did not incorporate a cleaning step
    • Can reduce microbial load 4-6 log10
    • Many studies have shown effectiveness of these products to eliminate infectivity of prions
2010 shea guideline cont background10
2010 SHEA Guideline cont.Background
  • 2) studies have been done using tissue homogenates (lumps of tissue). The tissue protects the prion and may be the reason the prion is so difficult to destroy.
  • 3) Studies have involved differing methodologies
2010 shea guideline cont
2010 SHEA Guideline cont.

What we do know:

  • Chlorine and NaOH provide the most consistent inactivation results but are corrosive to instruments and sterilizers and harmful to workers
  • Certain enzymatic cleaners and alkaline detergents do inactivate prions
  • Ethylene oxide does not work
2010 shea guideline cont12
2010 SHEA Guideline cont.

What we do know:

  • Transmission based on instrument contact with infected pt must retain its infectivity and that of adhering tissue after disinfection / sterilization must make contact with a receptive tissue (patient).
2010 shea guideline cont13
2010 SHEA Guideline cont.
  • The recommendations in this guideline are designed to break the chain of transmission and
  • Are predicated on epidemiological (evidence-based) studies. Other studies have been based on inactivation studies using lumps of tissue.
2010 shea guideline cont14
2010 SHEA Guideline cont.

Review: The 3 Parameters to consider:

  • Patient’s risk of having prion disease
  • Comparative infectivity of body tissue(s) involved
  • Intended use of the medical device
2010 shea guideline cont15
2010 SHEA Guideline cont.

At risk patient:

  • Rapidly progressive dementia
  • Ataxia (movement disorder)
  • Positive CSF 14-3-3 / tau protein / NSE
  • MRI and/or EEG consistent with CJD
  • Known risk – history of dura matter or growth hormone transplant
  • No other diagnosis to support S & S

No. 3 - 6 may not be present

2010 shea guideline cont16
2010 SHEA Guideline cont.

At risk tissues

  • High risk = brain, spinal cord, posterior eye (including retina, cornea and optic nerve), pituitary
  • Low risk = CSF, liver, lymph, kidney, lung, spleen, placenta, olfactory epithelium
2010 shea guideline cont17
2010 SHEA Guideline cont.
  • No risk = blood / blood products / components, bone marrow, peripheral nerves, intestine, heart, skeletal muscle, adipose, gingival, prostate, tears, saliva, sputum, urine, feces, sweat, breast milk, vaginal secretions, thyroid

Rutala and Weber, 2010

2010 shea guideline cont18
2010 SHEA Guideline cont.

Review: Spaulding’s Principles

  • Critical device: enters sterile tissue or vascular system
  • Semi-critical: contact non-intact skin or mucous membranes

Special reprocessing necessary for these devices if potentially prion contaminated

2010 shea guideline cont19
2010 SHEA Guideline cont.

Recommendations

  • Keep instruments wet until decontamination takes place
    • Immerse in water or prioncidal detergent (references included)
    • Do not let them dry out
  • Decontaminate (clean) in automated washer – disinfector ASAP after use to remove tissue
2010 shea guideline cont20
2010 SHEA Guideline cont.

Recommendations

  • After cleaning options:
    • 134˚C for 18 min pre-vacuum
    • 132˚ C for 1 hr gravity displacement
    • 1 N NaOH for 1 hr; rinse with water, autoclave in open pan (121 or 134˚C)
    • 1N NaOH for 1 hr, heat in gravity displacement at 121˚C 30 min, then clean and routine sterilize

Rutala and Weber, 2010

2010 shea guideline cont21
2010 SHEA Guideline cont.

Recommendations

  • Discard devices impossible to clean
  • Do not use flash sterilization
  • Recall contaminated items from pts later diagnosed with prion disease and reprocess using prion guideline protocol
  • Establish policies for all pts undergoing brain biopsy
2010 shea guideline cont22
2010 SHEA Guideline cont.

Recommendations

  • No recommendation for prion reprocessing for critical or semi-critical devices contaminated with low-risk tissue from a high risk patient.
  • Autopsy and research lab surfaces contaminated with high-risk tissue should be decontaminated with 1:5 bleach, contact time: 15 min

Rutala and Weber, 2010

2010 shea guideline cont23
2010 SHEA Guideline cont.

Recommendations

Quote from the authors: “…we have included only those options for which scientific studies have best demonstrated both safety (for equipment and operator) and efficacy.”

Rutala and Weber, 2010

2010 shea guideline cont24
2010 SHEA Guideline cont.

Recommendations

  • Environmental surfaces contaminated with no risk tissue from high-risk patients require standard / routine disinfection.

Rutala and Weber, 2010

2010 shea guideline cont25
2010 SHEA Guideline cont.

Recommendations

  • Consider using these recommendations for non-specific brain biopsies done on all patients with a non-space occupying lesion or
  • Use disposable instruments or
  • Routinely quarantine instruments
2010 shea guideline cont26
2010 SHEA Guideline cont.

Recommendations

  • If prion disease discovered after the fact, recall and reprocess instruments using special processes previously described, or
  • Discard the instruments
  • To do this you need a detailed tracking system
2010 shea guideline cont27
2010 SHEA Guideline cont.

General IP Precautions for prion disease

  • Standard precautions
  • No special precautions for food, utensils or environmental cleaning, disposal of blood or body fluids
  • No evidence of occupational transmission
  • No need to discard expensive lab or central processing instruments
2010 shea guideline cont28
2010 SHEA Guideline cont.

This document has been endorsed by:

  • SHEA
  • APIC
  • AORN
  • AAMI
  • This guideline will be updated as appropriate if/when scientifically proven new technologies are available.

Rutala and Weber, 2010

reply from belay et al cdc to rutala and weber december 2010 iche shea journal
Reply from Belay et al, CDC to Rutala and Weber – December 2010 ICHE / SHEA Journal
  • Recommendations are contrary to those endorsed by other recognized experts in the field
  • Contrary to the WHO 1999 Guideline
  • Lack of reported iatrogenically transmitted cases may not be as reassuring as Rutala and Weber assert
  • CDC, FDA, NIH continue to endorse WHO 1999 protocol
reply from rutala and weber to belay et al
Reply from Rutala and Weber to Belay et al

1) WHO document is not an evidence-based guideline and does not list the scientific studies used to support it

2) Agree the perfect test system type of study does not exist, but believe efficacy of protocols should place greater weight on studies representative of current standard instrument reprocessing

3) Rutala/Weber place more weight on lack of reported iatrogenic cases

4) Careful review of studies indicates conflicting results, probably due to use of different methodology

reply from rutala and weber to belay et al31
Reply from Rutala and Weber to Belay et al

5) Disagree with Belay et al on determination of mean infectivity likely present in human brain

6) Agree instruments should be kept moist until cleaned

7) Protocols in SHEA Guideline are consistent with SHEA, APIC, AORN, AAMI

the controversy continues
The Controversy continues…
  • Which document should you use?
  • What about cataract surgery?
  • What about automated, expensive lab instruments?
the controversy continues33
The Controversy continues…
  • Which document should you use?
    • WHO vs Rutala & Weber
    • ??
the controversy continues34
The Controversy continues…
  • What about cataract surgery?
    • Risk of transmission from routine cataract surgery is unknown. CDC is unaware of this ever having occurred.
    • Eye surgery of any kind on a suspect or known CJD pt should be done with disposable instruments or instruments must be reprocessed according to prion protocol

CDC website

the controversy continues35
The Controversy continues…
  • What about automated, expensive lab instruments?
    • In CSF is not a high risk tissue. No need to decontaminate or discard the automated lab analyzers
    • Rutala and Weber, 2010
hospital policy and procedures for neurosurgery
Hospital Policy and Procedures for Neurosurgery
  • Increase level of awareness of prion disease in all surgery cases involving high risk tissue
  • Establish high level of communication between OR and IP
  • Ensure policies and procedures are up to date
hospital policy and procedures for neurosurgery38
Hospital Policy and Procedures for Neurosurgery
  • Policy should include:
    • If prion disease is suspected after surgery, instruments involved will be recalled and properly reprocessed.
    • Instruments that cannot withstand prion reprocessing will be discarded
    • Designated coordination of exposure response, if necessary
hospital policy and procedures for neurosurgery39
Hospital Policy and Procedures for Neurosurgery
  • Policy should include:
    • All patients undergoing surgery to brain, spinal cord or eyes should be screened for S&S suggestive of prion disease
    • Notification that a patient with possible prion disease should be made to a defined group of people (e.g., IP, hospital epidemiologist, OR)
    • Surgery on such pts will be with disposable instruments
hospital policy and procedures for neurosurgery40
Hospital Policy and Procedures for Neurosurgery
  • Policy should include:
    • Training requirements
    • Safety issues (OSHA)
    • Forms necessary (e.g., pt screening)
    • References
    • Responsibility for policy coordination
    • Review process with by affected departments
hospital policy and procedures for neurosurgery41
Hospital Policy and Procedures for Neurosurgery
  • Procedure should include:
    • Prion disease should be considered in any pt with rapidly progressive dementia and/or movement disorders
    • Pt screening for prion disease shall be performed on all pts scheduled for surgery on brain, spinal cord, eye
      • Designate who will screen pt
      • Parameters for screening
hospital policy and procedures for neurosurgery42
Hospital Policy and Procedures for Neurosurgery
  • Procedure should include:
    • In event of possible or confirmed case
      • Notification of persons responsible for coordinating response
      • Be specific (e.g., IP, OR, CS, pathology, lab, Env. Services, etc.)
      • Delineate responsibilities of these individuals
hospital policy and procedures for neurosurgery43
Hospital Policy and Procedures for Neurosurgery
  • Procedure should include:
    • Delineate exact precautions to be used during surgery
      • Disposable instruments if possible
      • If using reusable instruments, they should be sequestered, kept moist, etc
      • Instrument quarantine details
      • Removal of unnecessary equipment prior to procedure
      • Schedule as last case of the day
hospital policy and procedures for neurosurgery44
Hospital Policy and Procedures for Neurosurgery
  • Procedure should include:
    • Enhanced cleaning of contaminated OR or lab surfaces (concentration, contact time)
    • Enhanced reprocessing of instruments – include detailed check list
      • Those which are disposable
      • Those which can withstand prion reprocessing
      • Quarantine parameters for others
      • Bin / instrument labeling
hospital policy and procedures for neurosurgery45
Hospital Policy and Procedures for Neurosurgery
  • Procedure should include:
    • Re: quarantined instruments
      • What to do if prion disease if definitively ruled out
      • What to do if prion disease is confirmed
      • Any special handling issues
2010 shea guideline cont47
2010 SHEA Guideline cont.
  • Transmission to 2 pts via brain electrodes is only proven transmission via a medical device:
      • Implanted in known CJD pts
      • Then cleaned and “sterilized” with benzene and 70% alcohol + formaldehyde vapor
      • 2 years later - retrieved and implanted in chimpanzee which eventually developed the disease
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