Download Basics of Airborne Infection Control

Basics of Airborne Infection
Control
Michele L. Pearson, MD
Division of TB Elimination
National Center for HIV, Viral Hepatitis,
STD, and TB Prevention
Building Design and Engineering Approaches to Airborne
Infection Control
Boston, MA
August 2010
Objectives
• Define Infection Control and discuss
public health importance of Infection
control
• Review categories of isolation
precautions
• Discuss airborne infections and
hierarchy of infection control measures
2007 Guideline for Isolation
Precautions: Preventing
Transmission of Infectious Agents
in Healthcare Settings
http://www.cdc.gov/ncidod/dhqp/pdf/isolation2007.pdf
Guidelines for Environmental
Infection Control
in Health-Care Facilities
MMWR June 6, 2003 / 52(RR10);1-42
What is Infection Control?
• Work practices and other measures
designed to prevent transmission of
infectious agents (break chain of
contagion)
– Patient to patient
– Patient to healthcare worker (HCW)
– HCW to patient
– HCW to HCW
– Visitors
Healthcare-Associated Infections
Home
Acute Care
Tranquil Gardens
Nursing Home
Long Term Care
Outpatient/
Ambulatory
Facility-associated Infections
•
•
•
•
•
Prisons and jails
Homeless shelters
Daycare centers
Dormitories
Barracks
CDC Categories of Isolation
Precautions
Standard:
• Merger of Universal
Precautions and Body
Substance Isolation
• Used for all patients
Transmission-based:
• Includes Airborne,
Droplet and Contact
• Used in addition to
Standard Precautions
• Incorporates all
previous CDC
isolation systems.
COMPONENTS OF STANDARD
PRECAUTIONS
Glove use
Mask & eye
protection
Routine cleaning/
disinfection
Hand hygiene
Sharps safety
Gown use
Respiratory Hygiene/Cough
Etiquette
• A combination of measures designed to
minimize transmission of respiratory
pathogens in healthcare settings
• Measures targeted to all patients with
symptoms of respiratory infection, beginning
at point of initial encounter (e.g., clinicians
offices, reception/triage of emergency
departments ambulatory clinics)
Components of Respiratory
Hygiene/Cough Etiquette Program
1. Posted signs/alerts to patients and family
members
2. Covering mouth/nose when coughing with tissues
or masks
3. Hand hygiene after contact with respiratory
secretions
4. Spatial separation (ideally > 3 feet) of persons with
respiratory infections, whenever possible
5. Droplet precautions for healthcare workers who
provide care to patients with possible respiratory
infections
HAND HYGIENE and GLOVES
• Gloves should be worn when contacting
potentially contaminated sites or handling
materials
• Warm water and soap or alcohol-based hand
rub (>60% alcohol)
Improved Patient Outcomes associated
with Proper Hand Hygiene
Ignaz Philipp Semmelweis
(1818-65)
Chlorinated lime hand antisepsis
Hand Hygiene Adherence in
Hospitals
Year of Study Adherence Rate Hospital Area
1994 (1)
29%
General and ICU
1995 (2)
41%
General
1996 (3)
41%
ICU
1998 (4)
30%
General
2000 (5)
48%
General
1. Gould D, J Hosp Infect 1994;28:15-30. 2. Larson E, J Hosp Infect 1995;30:88-106. 3.
Slaughter S, Ann Intern Med 1996;3:360-365. 4. Watanakunakorn C, Infect Control Hosp
Epidemiol 1998;19:858-860. 5. Pittet D, Lancet 2000:356;1307-1312.
CONTACT PRECAUTIONS
• Hand hygiene
• Gloves and gowns for all patient
contacts
• Dedicated noncritical patient-care
items, when possible
• Private room or cohort
• Limit patient movement/transport
to essential purposes only
DROPLET PRECAUTIONS
• Private room or cohort
• No special ventilation requirements;
door may remain open
• Use of mask when providing direct care
or within 3 feet of patient
AIRBORNE PRECAUTIONS
• Private room with monitored negative
air pressure
• 6-12 air changes per hour
• High efficiency particulate air (HEPA)
filtration for recirculated air
• HCWs wear respirators (minimum N95)
• Limit patient movement/transport to
essential purposes only
Possible sources of airborne
nosocomial infections
• Inside the facility
– Patients, healthcare workers, visitors
– Infected dusts or aerosols
– Ventilation and air-conditioning systems
• Outside the facility
– Soil
– Cooling towers
– Construction and renovation
Eickoff, ICHE 1994
AIRBORNE PRECAUTIONS
Disease
Room
Mask/Respirator
Immune Non-Immune
Varicella/
Disseminated
zoster
AIIR
None
Mask *
Measles
AIIR
None
Mask *
Tuberculosis
AIIR
NA
Respirator
SARS
Smallpox
VHF
Novel flu
AIIR
AIIR
AIIR
AIIR
NA
Respirator **
NA
NA
Respirator
Respirator
Respirator
Respirator
Respiratory Aerosols
• Droplets
most droplets >10 μm
> 30 μm
>100 μm
• Droplet nuclei
≤ 5 μm
1-10 μm
Particles <10 μm enter the lower respiratory tract
Droplets vs. Droplet Nuclei
(Droplet vs Airborne Precautions)
Size
(µm)
Time to fall
1m
Distance to
touchdown
(m)
1
Velocity time to
settling
(m/s)
3.50E-05
7.9 h
240
5
7.80E-04
21 m
11
10
2.90E-03
5.7 m
2.9
50
2.90E-03
13 s
0.11
100
1.70E-01
5.9 s
0.049
Roy et al. NEJM 2004;350;17
Framework for Approaching Control
Strategies: Prevention and Control of
Exposure to Environmental Hazards
• Primary prevention of exposure--control at the
source (administrative controls)
• If can not be achieved, exposure should be
reduced along the path (ventilation, protective
barriers, related measures)
• As a last stop, exposure should be controlled at
the level of the person (personal protective
equipment)
Administrative controls
•Isolation/separation
•Masks
•Effective treatment
Administrative controls
Administrative
Controls
Environmental
Controls
Administrative controls
Environmental Controls
Dilution (ventilation)
Removal (Fans)
Decontamination (UVGI)
Administrative controls
Environmental Controls
Administrative controls
Environmental Controls
Respiratory Protectio
EDUCATION
Fundamentals of Airborne Infection
Control
Hierarchy of Infection Control Measures
Administrative Controls
Environmental Controls
Respiratory Protection
THANKS!
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