Biological and Chemical Hazards in Clinical Engineering
2016-01-04 rev
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Biological and Chemical Hazards
in
Clinical Engineering
© D. J. McMahon 150106
rev cewood 2016-01-04
The Enemies
Micro-organism: any microscopic organism made of either a
single cell, cell clusters, or no cell at all.
Germ or Pathogen: a microorganism that causes disease.
Bacteria: single-celled microorganisms of many possible shapes,
that have no nucleus.
Virus: organism with DNA or RNA, protein, and a layer of lipid
Fungus: multi-celled organism with a nucleus.
Includes yeasts and molds. Favor cool, moist, dark environments.
Spore: self-reproductive form of a micro-organism that is
hardened against hostile environments. e.g. tuberculosis:
Prion: an infectious non-microorganism made of
‘misfolded’ protein, with no nucleus. Self-reproduces in specific tissue.
http://www.slideshare.net/sarah_jumali/7-control-of-microbial-growth-7315899
Biological Hazards –
Can be transmitted by three vectors:
- Body Fluids (“Bloodborne”)
(blood, saliva, urine, pus, etc…)
- Droplets (usually respiratory)
- Airborne microorganisms
Bloodborne transmission occurs through:
> accidental needlesticks
> cuts or scrapes of the skin
> contact with mucosa:
- eyes, nose, mouth
but NOT by shaking hands, conversing, or eating
with an infected person.
Staphyloccocus aureus ( “Staph” )
Bacteria
Streptococcus pyogenes ( “ Strep” )
Bacteria
Bacteria
Bacteria
Bloodborne Pathogens - virus
The Big Three for Health Care Workers:
> Hepatitis B Virus (HBV)
> Hepatitis C Virus (HCV)
> Human Immunodeficiency Virus (HIV)
- primary agent of
Acquired Immune Deficiency Syndrome (AIDS)
There is no cure for any of these at this time.
Hepatitis A Virus (HAV)
note: NOT one of the Big Three, has similar name
- relatively common
- primarily food-borne, spread by feces
- symptoms:
yellow eyes, dark urine, nausea, fever, etc.
- not fatal
- recovery produces immunity for life
- However, if you had Hepatitis A when you were
11 years of age or older, you cannot donate
blood.
- vaccination requires two shots, 6 - 12 months
apart
Hepatitis B Virus (HBV)
- Hepatitis (HBV & HCV) is the seventh leading killer
worldwide (2013; source: WHO)
- Fastest spreading variant of hepatitis
- Spread by blood or other bodily fluids
- About 8000 US Health Care Workers
contract HBV annually, and about 200 die
-Takes several months for full symptoms:
fatigue, weight loss, fever, stomach pain,
nausea, muscle & joint pain
Hepatitis B (HBV)
- Usual recovery in ~6 months, but chronic
infection can cause serious liver damage.
- Hope for a cure ‘on the horizon’, based on antiviral
drugs
- Vaccination requires three shots over 6 months.
- OSHA requires that employers offer vaccination
for HBV to employees who are routinely exposed
to blood & body fluids.
- Biomed techs deal with much equipment that is
contaminated. We should be vaccinated.
Hepatitis C Virus (HCV)
- Somewhat less dangerous than HBV, but still a risk
- Blood-borne and transmitted by blood exposure
- Infection determined by blood test, if at risk
- Can be asymptomatic
- Attacks liver; symptoms (if any) similar to HBV
- Can result in cirrhosis & liver damage in long term
- There is no vaccine for HCV; prevention is key
- New expensive ‘cocktail’ antiviral drugs coming to
market now with high rate of cure
Human Immunodeficiency Virus (HIV)
- primary agent of Acquired Immune Deficiency Syndrome
(AIDS)
- Attacks the normal immune system, making it difficult to
defend against other disease.
- Symptoms within weeks:
fever, night sweats, fatigue,
swollen lymph nodes,
white spots in mouth.
- HIV infections are potentially fatal.
- There is no vaccine (biological preparation that provides
active acquired immunity to a particular disease)
Ebola (also called: EVD, Ebola virus disease,
and ebola hemorrhagic fever)
• Ebola is a rare and deadly disease caused by infection with a strain of Ebola virus.
• Ebola is spread through direct contact with blood and body fluids of a person
already showing symptoms of Ebola.
• Ebola is not spread through the air,
water, food, or mosquitoes.
• The 2014 Ebola epidemic is the largest
in history, affecting multiple
countries in West Africa.
• The risk of an Ebola outbreak affecting
multiple people in the U.S.
is very low. (Source: cdc.gov)
Major Bacterial Infections:
- MRSA Methicillin Resistant staphylococcus aureus
resistant to all penicillins
- Clostridium difficiles (called “C. diff”)
causes serious intestinal unbalance
- CRE bacteria Carbapenem-resistant enterobacteria
(considered the "drug of last resort" for such infections
- Legionnaires’ Disease
bacterial pneumonia
- Necrotizing faciitis (“flesh-eating disease”)
bacterial infection of soft tissue (30% fatality)
Other major infections:
Prion-based diseases:
( Prion: Virus-like protein, without a nucleus )
- BSE (Bovine Spongiform Encephalopathy)
- (“Mad Cow” Disease)
- Creutzfeldt-Jacob Disease (“CJD”)
- close relative of BSE
Both are fatal degenerative brain diseases
which are transmissible and difficult to kill.
more info: http://memory.ucsf.edu/cjd/overview/types
Spongiform Encephalopathy
Definitions
- Antiseptic: germicide for use on living tissue
- Antibiotics or antibacterials: a type of antimicrobial used in the treatment and
prevention of bacterial infection. They may either kill or inhibit the growth of bacteria
- Cleaning: removal of foreign material, using disinfectant and friction
- Disinfection: process that only kills vegetative bacteria
( Can be low, intermediate, and high levels )
- Decontamination: process that renders a surface safe to handle
but not totally free of microorganisms
- Sterilization: any process that renders a surface completely free of microorganisms
- Pasteurization: High-level disinfection (HLD)
by the use of moderate heat (71-76° C) for ~30 minutes
Universal precautions is the practice of
avoiding contact with bodily fluids, by
means of the wearing of nonporous
articles such as gloves, goggles, and face
shields.
The practice was introduced in 1985.
In 1996, this term was
replaced with the term
standard precautions.
-OSHA
Basics of Infection Control
the basic level of infection control that should be used in the care of
all patients all of the time:
treat all blood and bodily fluids as
infectious at all times
“Standard Precautions”
1:
2:
3:
4:
5:
6:
Hand washing
Barriers
Sharps Management
Equipment & Supply Storage
Spill Management
Biohazard Waste Management
1: Handwashing
The single most effective vector for disease in the workplace is the
hands.
The single most effective infection control practice is
immediately washing your hands (or any other skin)
that comes in contact with blood or fluid.
Use conventional soap-&-water:
15+ second scrub, or supplement.
“Gel-in, Gel-out”
Most hospitals have a strict requirement that all employees use
a hand sanitizer when entering and leaving a patient’s room.
UCSF Medical Center:
2: Barriers
Personal Protection Equipment (PPE)
- Always changed for a single event
- Gloves, gown, and mask with face and eye
protection.
- Eye protection should include shielding
of the temporal aspects (sides).
3: Sharps Management
Most blood / fluid infection by HCWs is from used sharps.
Biomed techs are not exempt.
- Never re-cap, bend, or break needles.
- Always put used sharps in designated sharps containers.
- All other potentially contaminated items
should go into a red bag.
- Watch for the biohazard symbol:
4: Equipment & Supply Storage
- No storage under plumbing (e.g. sinks).
- Separate and label ‘Clean’ from ‘Dirty’
everything must be labeled.
- Should be an SDS (MSDS) sheet for everything.
- Dirty equipment should be thoroughly cleaned.
Take your time.
5: Spill Management
- Use barriers
- Use a tool to pick up sharps
- Soak up contaminants with absorbent media
(paper towels, gauze, etc.) and discard safely
- Clean and then disinfect with an appropriate agent
(Virex, 10% bleach)
6: Biohazard Waste Management
- Use the appropriate container
- Dispose of liquids down the drain if possible
- Check with Environmental Services with any
special issues:
- Lead-acid batteries
- Lithium batteries
- Caustic agents
- Acids
Three Levels of Precautions:
1: Contact Precautions:
- In areas where there is chance of exposure to
bloodborne pathogens:
> Do NOT eat, drink, or use lip balm
> Do NOT store food,
> Do NOT apply cosmetics or contact lenses.
- Use PPE: gowns, gloves, masks
Do NOT eat at your biomed workbench !!
2: Droplet Precautions:
- Respiratory infections
e.g. pertussis (whooping cough), rubella
- Face and eye protection if within 3 to 5 feet of
the patient
- Gloves & gown if in contact with infective
material
3: Airborne Precautions:
- Measles, chicken pox, tuberculosis (TB)
- Private room, with negative airflow
- Patient must be masked if out of room
- Use of PAPR and UV light
- Room must be closed for 2 hours after the
patient leaves
PAPR: Powered Air Purifying Respirator
Battery operated respirator. Consists of a half or full facepiece,
breathing tube, battery-operated blower, and HEPA particulate filters.
Uses a blower to pass contaminated air through the HEPA filter,
which removes the contaminant and supplies purified air to a facepiece.
HEPA: "High Efficiency Particulate Air"
PAPR cart:
(outside the room)
Examples of Biohazards:
Ventilators especially the patient
circuit components
Examples of Biohazards:
Examples of Bio Hazards:
Clinical Lab equipment
an SCD; looks clean enough...
eeeeeeeew!
wonder what’s
wrong with the
power switch...
UV Disinfection
In use since 2007. Uses UV-C, the germicidal short-wavelength UV.
type of UV
Wavelength (nm)
Ultraviolet A (UVA) 315-400
Ultraviolet B (UVB) 280-315
Ultraviolet C (UVC) 100-280
Tru-D
Xenex Disinfection System
Example of
Bio Hazard
Abatement:
Neptune System:
Fluid waste
management
system for O.R.
Building Invasions
& Construction Sites
Asbestos, dust, and mold can be thrown into
the environment whenever walls or ceilings are
opened for remodeling, cable pulling, etc.
- especially threatening to acute care patients
or immuno-suppressed patients
Barriers must be used
All invasions must be sealed-up
Primarily an issue for Facilities Engineering
Exposure Threats from
Non-Biological Agents:
- smoke plume from cautery and from lasers
- N2O in anesthesia settings
- anesthetic agents
- mercury (Hg) (clinical laboratory)
- chemotherapeutics
- various organic solvents
- x-rays
- radioisotopes in Nuclear Medicine
Chemotherapy hazard management --
Waste anesthetic gases (WAGs) :
- OSHA / NIOSH requires testing for N2O in areas where
anesthetics are given.
- Waste anesthetic gases have been statistically associated
with high incidents of cancer and birth defects in surgical
personnel.
- Testing should be done at least annually, using personal
exposure badges.
- Upper limit is 25 ppm for N2O, on an 8-hour time-weighted
average, per NIOSH.
Safety Data Sheet
‘SDS’
(was “Materials Safety Data Sheet”: MSDS)
- Gives complete info on the nature, hazards, and exposure management of any agent.
- Part of “Globally Harmonized System”
- Much more readable than MSDS
- OSHA’s “Right to Know” law requires that you have access to SDS’s for anything in
your work setting, and that an employer provides safety equipment.
- SDS’s are often accessible to employees in
web-based format (usually by subscription).
- Available to the public (with some searching)
start here:
http://www.ilpi.com/msds/
Sections of every SDS:
The Hazard Communication Standard (HCS) requires chemical manufacturers, distributors, or importers
to provide Safety Data Sheets (SDSs) (formerly known as Material Safety Data Sheets or MSDSs) to
communicate the hazards of hazardous chemical products.
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
Identification
Hazard(s) identification
Composition/information on ingredients
First-aid measures
Fire-fighting measures
Accidental release measures
Handling and Storage
Exposure controls/personal protection
Physical and chemical properties
Stability and reactivity
Toxicological information
Ecological information
Disposal considerations
Transport information
Regulatory information
Other information
Infection Control Officer / Department
Required by The Joint Commission for any healthcare delivery system
Association for Professionals in Infection Control and Epidemiology
Employee Occupational Health
- Get tested when first employed
(usually required by your employer).
- If exposed, get to Employee Health
or the ED immediately.
- Report exposures to your supervisor.
- Keep your immunizations current.