tb infection control: engineering (environmental) controls kevin p. fennelly, md, mph division of...
TRANSCRIPT
![Page 1: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/1.jpg)
TB Infection Control:Engineering (Environmental)
Controls
Kevin P. Fennelly, MD, MPHDivision of Pulmonary & Critical Care Medicine
Center for Emerging PathogensUMDNJ-New Jersey Medical School
![Page 2: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/2.jpg)
Objectives• To review fundamental principles and practices of
TB infection control related to engineering controls
• To discuss advantages and limitations to different engineering control measures.
• To discuss how engineering controls are used in the total TB Infection Control Plan.
• To discuss issues and questions specific to your experiences in Chiapas.
![Page 3: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/3.jpg)
Key Points• Engineering controls (EC) are the 2nd priority in
control measures AFTER administrative controls, • But they are complementary
• Dilution ventilation is the most important EC– Protects HCWs, other patients, visitors– Has limits defined by technology, expense, comfort
• Negative pressure or directional airfllow keeps contaminated air away from HCWs
• UVGI and filtration devices are adjuncts or back-ups for high-risk areas– Require maintenance– Need to consider cost-effectiveness
![Page 4: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/4.jpg)
• Administrative controls: reduce risk of exposure
• Environmental controls: prevent spread and reduce concentration of droplet nuclei
• Respiratory protection controls: further reduce risk of exposure to wearer only
Fundamentals of Infection Control
![Page 5: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/5.jpg)
Hierarchy of Infection Control
Respiratory Protection
Administrative Controls
Environmental Controls
![Page 6: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/6.jpg)
Hierarchy of Infection Controls
Administrative
Administrative
Environmental
EnvironmentalRespiratory
Respiratory
protection
protection
Worke
r
Worke
r
Patient
Patient
Setting
Setting
![Page 7: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/7.jpg)
TB-Infection Controls: Simplified
• Administrative: WHO?– Who is a TB suspect?– Who is at risk from exposure?– Who has infectious TB?– Who has drug resistant TB?
• Environmental: WHERE?– Where is optimal place to minimize risk?
• Personal Respiratory Protection: Special high risk settings
![Page 8: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/8.jpg)
Environmental Controls
• Control source of infection
• Dilute and remove contaminated air
• Control airflow – Keep infectious air moving outside– Keep HCWs ‘upwind’ , infectious patients
‘downwind’
![Page 9: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/9.jpg)
Airborne Infection Isolation Room Policies
• Environmental factors and entry of visitors and HCWs should be controlled
• Air changes per hour (ACH) (volume /time)– >6 ACH (existing)– >12 ACH (new)
• Minimum of 2 ACH of outdoor air• HCWs should wear at least N95 respirators
![Page 10: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/10.jpg)
10
What is ventilation?
• Movement of air
• “Pushing” and/or “pulling” of particles and vapors
• Preferably in a controlled manner
![Page 11: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/11.jpg)
11
Ventilation control• Types of ventilation
– Natural
– Local
– General
![Page 12: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/12.jpg)
Local exhaust ventilation
• Source capture
– Exterior hoods
– Enclosing hoods
Uganda
![Page 13: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/13.jpg)
Examples of General Ventilation
•Single pass– First choice
• Recirculating– HEPA filtration
![Page 14: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/14.jpg)
14
Room Air Mixing and Air Flow
• Prevent air stagnation• Prevent short
circuiting• Air direction• Air temperature• Space configuration• Movement
![Page 15: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/15.jpg)
• Clean to less clean
• Negative pressure
Facility Airflow Direction
![Page 16: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/16.jpg)
• Clean to less clean
• Negative pressure
Facility Airflow Direction
![Page 17: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/17.jpg)
17
BronchoscopyBronchoscopy
Brazil
![Page 18: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/18.jpg)
18
![Page 19: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/19.jpg)
- Escombe AR et al. Plos Med 2007 ; 4: e68
![Page 20: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/20.jpg)
- Escombe AR et al. Plos Med 2007 ; 4: e68
![Page 21: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/21.jpg)
![Page 22: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/22.jpg)
Natural vs Mechanical Ventilation
• Good natural ventilation is better than bad mechanical ventilation.
• Major limitation of natural ventilation is that it depends upon outdoor weather conditions.
• Can control odor and improve comfort of occupants , but not if very cold or very hot.
• Usually we do not have a choice and must work with where we are!
![Page 23: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/23.jpg)
Limitations of Ventilation
![Page 24: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/24.jpg)
24
HEPA filtration
Must be used– When discharging air from local exhaust
ventilation booths or enclosures directly into the surrounding room, and
– When discharging air from an AII room into the general ventilation system
![Page 25: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/25.jpg)
25
Room Air Cleaners
![Page 26: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/26.jpg)
26TB Outpatient unit – Helio Fraga Institute, MoH, Rio de JaneiroTB Outpatient unit – Helio Fraga Institute, MoH, Rio de Janeiro
![Page 27: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/27.jpg)
27
11
1010
100100
1,0001,000
00 22 44 66 88 1010
Elapsed Time (hours)Elapsed Time (hours)
Colo
ny F
orm
ing
Uni
ts (C
FUs)
Colo
ny F
orm
ing
Uni
ts (C
FUs)
Position 1 Position 2 Position 3Position 4Position 5Position 6Position 7Position 8Position 9
Linear
OffOff OnOn
Evaluation of Room Air Cleaners
![Page 28: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/28.jpg)
28
Ultraviolet Germicidal Irradition (UVGI)
• Used as supplement or back-up to dilution ventilation
• Does NOT provide negative pressure
• Requires maintenance, esp. cleaning bulbs
• Not effective at high humidity (>70%)
• Occupational exposure limits: eye & skin
![Page 29: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/29.jpg)
29
![Page 30: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/30.jpg)
Xu P et al. Atmospheric Environment 2003; 37:405
![Page 31: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/31.jpg)
31
![Page 32: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/32.jpg)
- Escombe AR et al. Plos Med 2009 (March) ; 6
![Page 33: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/33.jpg)
Escombe AR et al. Plos Med 2009 (March) ; 6
![Page 34: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/34.jpg)
Environmental Controls: Which one and When?
• Dilution ventilation, UVGI, and HEPA filter units are all effective under IDEAL laboratory conditions
• Best data in field support dilution ventilation• Advantage of ventilation is usually ‘always on’,
minimizing human errors.• Disadvantages of UVGI and HEPAs
– Maintenance (increased human errors)– Large variability of effectiveness– May cause false sense of reassurance
![Page 35: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/35.jpg)
Assumptions: Homogenous distribution of infectious aerosol over 10 hours; uniform susceptibility.
- Fennelly KP & Nardell EA. Infect Control Hosp Epidemiol 1998; 19;754
Control Measures are Synergistic & Complementary
![Page 36: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/36.jpg)
Wells-Riley Equation: Mathematical model of airborne
infectionPr{infection}=C/S=1-e(-Iqpt/Q)
Where
C=# S infected x S=# susceptibles exposed xI = # infectors (# active pulm TB cases) xq = # infectious units produced/hr/Infector xp = pulm ventilation rate/hr/St = hours of exposure xQ = room ventilation rate with fresh air
x
Admin E.C.
![Page 37: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/37.jpg)
Risk of Close Exposure?
![Page 38: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/38.jpg)
HCWInfectious Case
![Page 39: TB Infection Control: Engineering (Environmental) Controls Kevin P. Fennelly, MD, MPH Division of Pulmonary & Critical Care Medicine Center for Emerging](https://reader036.vdocuments.site/reader036/viewer/2022062518/56649d8a5503460f94a6ff6c/html5/thumbnails/39.jpg)
Summary – TBIC Engineering Controls
• First priority is ADMINISTRATIVE controls, but EC are complementary
• Dilution ventilation is most important for all– Can add to comfort– But limited by technology, comfort, expense
• Negative pressure or directional airflow can keep infected air away (even if diluted) from HCWs
• UVGI and filtration devices are adjuncts for high risk areas– Back-up when not possible to ventilate well