Expedient Methods for Surge Airborne Isolation within Healthcare Settings during Response to a ...

197 Pages·2013·8.93 MB·English

by  Ken Mead

In-Depth Report

Expedient Methods for Surge Airborne Isolation
within Healthcare Settings during Response to a
Natural or Manmade Epidemic

Kenneth R. Mead, Ph.D., P.E.
Amy Feng, M.S.
Duane Hammond, M.S., P.E.
Stan Shulman, Ph.D.

Division of Applied Research and Technology
Engineering and Physical Hazards Branch
EPHB Report No. 301-05f

Veterans Administration Medical Center, Oklahoma City, Oklahoma
Central Kansas Medical Center, Great Bend, Kansas
St. Joseph Memorial Hospital, Larned, Kansas
INTEGRIS Baptist Medical Center, Oklahoma City, Oklahoma

April 2012
DEPARTMENT OF HEALTH AND HUMAN SERVICES
Centers for Disease Control and Prevention
National Institute for Occupational Safety and Health
EPHB Report No. EPHB 301-05f

Research Locations: Veterans Administration Medical Center
Oklahoma City, OK
Central Kansas Medical Center
Great Bend, KS
St. Joseph Memorial Hospital
Larned, KS
Integris Baptist Medical Center
Oklahoma City, OK
NAICS Code: 622110 (General Medical and Surgical
Hospitals)
Research Period: July 2003—May 2008
Surveys Conducted By: Kenneth R. Mead, Ph.D., P.E.
NIOSH, Cincinnati, OH
Duane Hammond, M.S., P.E.
NIOSH, Cincinnati, OH
Adam Paberzs
Formerly NIOSH, Cincinnati, OH
Brian Adams
Formerly NIOSH, Cincinnati, OH
Facility Representatives Veterans Administration Medical Center
Contacted Phil Comp, MD
Director of Research
Janey Wooley, RN
Vice-chair of Nursing
Beverly Stiles, RN
Ward Nurse
Central Kansas Medical Center (CKMC)
Chris Thomas, CHE, MBA
President/CEO

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EPHB Report No. EPHB 301-05f

Nancy Winkelman, RN, ICP
Manager Infection Control, Employee
Health, Patient Education, Workers
Compensation Coordinator
St. Joseph Memorial Hospital
Previously identified CKMC
Representatives plus
Danielle Johnson, MA
Hospital Administrator
John Broderway
Environmental Services Manager
Integris Baptist Medical Center
Harry J. Goett, CIH
System Industrial Hygienist
Barbara Morton, RN, BSN
Clinical Director, 9-East

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EPHB Report No. EPHB 301-05f

Disclaimer
Mention of any company or product does not constitute endorsement by NIOSH. In
addition, citations to websites external to NIOSH do not constitute NIOSH
endorsement of the sponsoring organizations or their programs or products.
Furthermore, NIOSH is not responsible for the content of these websites. All Web
addresses referenced in this document were accessible as of the publication date.

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Table of Contents
Disclaimer ........................................................................................ iii
List of Tables .................................................................................... iv
List of Figures ................................................................................. viii
Chapter I .......................................................................................... 1
Introduction and Literature Review .................................................... 1
History: Airborne Disease Transmission Theory ......................................... 1
The Development of Droplet Nuclei Theory ............................................... 4
Droplet Nuclei: From Theory to Human Contagion...................................... 8
The Evolution of Standardized Hospital Isolation Criteria ........................... 10
The CDC Weighs In .............................................................................. 11
OSHA Proposes Bloodborne Pathogens Regulation ................................... 12
CDC Isolation Precautions for Control of Tuberculosis ............................... 13
The Hospital Infection Control Practices Advisory Committee ..................... 15
Pathogens of Interest for Airborne Isolation ............................................ 16
Engineering Design Standards for Hospital Isolation ................................. 18
Potential Lessons from Industrial Contaminant Control Theory .................. 22
Summary of Background Issues and Recent Events ................................. 28
Problem Statement .............................................................................. 30
Purpose and Scope .............................................................................. 30
Chapter II ....................................................................................... 31
Methods and Materials ................................................................... 31
Expedient Isolation Configuration Descriptions .................................. 32
Surrogate Aerosol Source Generation—Protocol Development ............. 36
Testing Platform and Set-up Description ................................................. 36
Aerosol Generation Technique ............................................................... 38
Preliminary Work to Develop the Generation Protocol ............................... 40
Validation of the Generation Protocol ...................................................... 45
Validation Results ................................................................................ 46
Validation Conclusion ........................................................................... 50
Field Equipment and Methodology ................................................... 50
Configuration Setup ............................................................................. 50
Experimental Procedure ........................................................................ 56
Patient Source Generation (Order of Operation) ....................................... 57

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Data Collection and Management ........................................................... 57
Data Analysis ................................................................................ 58
Air Filter Sampling and Particle Counting .......................................... 60
Chapter III ...................................................................................... 61
Results ......................................................................................... 61
Oklahoma City Department of Veterans Affairs Medical Center ............ 61
Zone-within-Zone, Two-Patient Configuration .......................................... 62
Ventilated Headboard, One-Patient Configuration .................................... 67
Central Kansas Medical Center, Great Bend, KS ................................. 71
Zone-within-Zone, Two-Patient Configuration .......................................... 72
Ventilated Headboard, One-Patient Configuration .................................... 78
St Joseph Memorial Hospital, Larned, Kansas .................................... 83
Zone-within-Zone, Two-Patient Configuration .......................................... 83
Ventilated Headboard, One-Patient Configuration .................................... 89
Zone-within-Zone, Two-Patient Configuration .......................................... 92
Ventilated Headboard, One-Patient Configuration .................................... 99
Summary of Physical Field Conditions ............................................ 104
Chapter IV .................................................................................... 106
Analysis and Discussion ................................................................ 106
Aerosol Spectrometer Data ................................................................. 106
Zone-Within-Zone Configuration .......................................................... 109
Ventilated Headboard Configuration ..................................................... 113
IH Sampling/Optical Particle Counting ............................................ 115
Impact of 0.03 Baseline Shift .............................................................. 117
HEPA Fan Motor Impact Upon Room Temperature ........................... 118
Physical Parameters ..................................................................... 119
Zone-Within-Zone Configuration .......................................................... 119
Ventilated Headboard Configuration ..................................................... 121
Chapter V ..................................................................................... 123
Summary ................................................................................... 123
Background ...................................................................................... 123
Research Methodology........................................................................ 123
Major Findings ................................................................................... 124
Implications ...................................................................................... 125

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Limitations ........................................................................................ 126
Suggestions for Further Research ........................................................ 127
Bed Position ...................................................................................... 127
Worker position/worker movement ...................................................... 127
Comparison Temporary Negative Pressure Isolation ............................... 127
Combining Ventilated Headboard and Zone-Within-Zone Configurations ... 128
Protective Isolation ............................................................................ 128
Nonhospital Environments .................................................................. 128
Conclusion .................................................................................. 128
Acknowledgement ....................................................................... 129
References .................................................................................... 129
Appendix A.................................................................................... 140
Appendix B ................................................................................... 152
Data Processing Steps and Statistical Results from SAS Proc Mixed Model
for Aerosol Spectrometer Data ...................................................... 152
Data Processing Steps ........................................................................ 152
SAS PROX MIXED (SAS Version 9.13)—Statistical Analysis and Model
Output Reports ........................................................................... 153
I. VETERAN’S ADMINISTRATION MEDICAL CENTER (VAMC), OKLAHOMA CITY,
OK ................................................................................................... 153
II. St JOSEPH MEMORIAL HOSPITAL (SJMH), LARNED, KS ...................... 156
III. CENTRAL KANSAS MEDICAL CENTER (CKMC), Great Bend, KS ........... 159
IV. INTEGRIS BAPTIST MEDICAL CENTER (IBMC), OKLAHOMA CITY, OK ... 162
Appendix C ................................................................................... 165
Industrial Hygiene Sampling Optical Counting Lab Results ................ 165

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List of Tables
Table 1. Ventilation requirements for variously termed isolation rooms (remodeled
or new construction), as prescribed by American Institute of Architects guidelines
(1987–2001) [American Institute of Architects 1987, 1993, 1996, 2001]. ........... 20
Table 2. Air changes per hour (ACH) and elapsed time required to achieve a desired
removal efficiency* ...................................................................................... 25
Table 3. Geometric mean reduction ratios (GMRRs), by sample position and test
condition code, from Grimm aerosol spectrometer results in the zone-within-zone
expedient isolation field study at the Oklahoma City VA Medical Center. ............. 65
Table 4. Geometric mean reduction ratios (GMRRs) for Grimm aerosol spectrometer
data (black values) and filter sampling/optical counting data (red values) collected
in the ventilated headboard expedient isolation field study at the Oklahoma City VA
Medical Center. ............................................................................................ 66
Table 5. Geometric mean reduction ratios (GMRRs) for Grimm aerosol spectrometer
data (black values) and filter sampling/optical counting data (red values) collected
in the ventilated headboard expedient isolation field study at the Oklahoma City VA
Medical Center. ............................................................................................ 70
Table 6. Summary of temperature data logged during ventilated headboard
expedient isolation field study at the VA Medical Center, Oklahoma City, OK. ...... 70
Table 7. Geometric mean reduction ratios (GMRRs), by sample position and control-
on condition code, from Grimm aerosol spectrometer data obtained at Central
Kansas Medical Center in the zone-within-zone expedient isolation field study. .... 76
Table 8. Summary of temperature data logged during zone-within-zone expedient
isolation field study at Central Kansas Medical Center, Great Bend, KS. .............. 77
Table 9. Geometric mean reduction ratios (GMRRs) for Grimm aerosol spectrometer
data (black values) and filter sampling/optical counting data (red values) collected
at Central Kansas Medical Center in the ventilated headboard expedient isolation
field study. .................................................................................................. 81
Table 10. Summary of temperature data logged during ventilated headboard
expedient isolation field study at Central Kansas Medical Center, Great Bend, KS. 82
Table 11. Geometric mean reduction ratios (GMRRs) for Grimm aerosol
spectrometer data (black values) and filter sampling/optical counting data (red
values) collected at St Joseph Memorial Hospital in the zone-within-zone expedient
isolation field study. ..................................................................................... 89
Table 12. Geometric mean reduction ratios (GMRRs) for Grimm aerosol
spectrometer data (black values) and filter sampling/optical counting data (red
values) collected at St Joseph Memorial Hospital in the ventilated headboard
expedient isolation field study........................................................................ 92
Table 13. Geometric mean reduction ratios (GMRRs) for Grimm aerosol
spectrometer data (black values) and filter sampling/optical counting data (red

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EPHB Report No. EPHB 301-05f

values) collected at the INTEGRIS Baptist Medical Center in the zone-within-zone
expedient isolation field study........................................................................ 97
Table 14. Summary of temperature data logged during zone-within-zone expedient
isolation field study at INTEGRIS Baptist Medical Center, Oklahoma City, OK. ...... 98
Table 15. Geometric mean reduction ratios (GMRRs) for Grimm aerosol
spectrometer data (black values) and filter sampling/optical counting data (red
values) collected at INTEGRIS Baptist Medical Center in the ventilated headboard
expedient isolation field study...................................................................... 102
Table 16. Summary of temperature data logged during the ventilated headboard
expedient isolation field study at INTEGRIS Baptist Medical Center, Oklahoma City,
OK. .......................................................................................................... 103
Table 17. Summary of field conditions associated with the four zone-within-zone
field studies conducted under this research. .................................................. 105
Table 18. Summary of field conditions associated with the four ventilated-
headboard field studies conducted under this research. .................................. 106
Table 19. Summary of geometric mean reduction ratios (GMRRs) and lower limits
(in parentheses) for the zone-within-zone (2-bed) expedient isolation field studies
at the four research sites; aerosol spectrometer data simultaneously corrected for α
= 0.10 (see Notes). .................................................................................... 108
Table 20. Protective Time Equivalent (minutes) provided by concentration
reductions generated by the zone-within-zone expedient isolation configurations.
............................................................................................................... 113
Table 21. Summary of geometric mean reduction ratios (lower limits in
parentheses) for the ventilated headboard expedient isolation field studies,
simultaneously corrected for α = 0.10. ....................................................... 114
Table 22. Protective Time Equivalent (minutes) provided by concentration
reductions generated by the ventilated headboard expedient isolation
configurations. ........................................................................................... 115
Table 23. Comparison of lower geometric mean reduction ratio limits (Redu Lim;
α = 0.10) for the CKMC IH sampling/optical counting results, with and without
0.03 baseline shift (BLS). ........................................................................... 118

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EPHB Report No. EPHB 301-05f

List of Figures
Figure 1. Swan flask. The swan-like neck was open to air, but dust and airborne
microbes could not navigate the contour to reach the contents. ........................... 1
Figure 2. Falling times and evaporation times of water droplets in air. (Graphic
created from data published in Epidemiologic Basis of Tuberculosis Control [Rieder
et al. 1999].) ................................................................................................. 6
Figure 3. Schematic detailing airborne transmission of smallpox at a hospital in
Meschede, Germany (1970), and the similar dispersion of tracer smoke tests
conducted later by the WHO [graphic: CDC]. ................................................... 10
Figure 4. Common air contaminants and their relative sizes (graphic: CDC/NIOSH).
................................................................................................................. 17
Figure 5. Photographs of some of the portable HEPA filtration equipment used
during the expedient isolation research. A portable freestanding unit with
nonducted inlet (left) and a portable dust-control unit, capable of ducted or
freestanding operation (right). ....................................................................... 32
Figure 6. Photo of patient mannequin positioned in front of a ventilated headboard
shows source generators (nebulizers) positioned next to the mannequin’s mouth
and an aerosol sampler positioned in the center of the mannequin’s chest. ......... 36
Figure 7. Schematic (7a) and photograph (7b) showing the testing platform used
for development of the aerosol generation protocol. ......................................... 38
Figure 8. Variation with nebulization time of aerosol particle counts, per liter of air
sampled, for the 1–2-µm size range. Extended nebulizer runs using two PSL
microsphere suspension concentrations revealed an apparent aerosol generation
rate inflexion point between 20 and 30 minutes of elapsed nebulization time. ...... 41
Figure 9. Graph of early nebulizer output, showing initial instability followed by an
apparently steady concentration increase. ....................................................... 42
Figure 10. Droplet nuclei generation rates after reducing testing platform back-
pressure and revising the PSL suspension formulation. ..................................... 43
Figure 11. Total count distribution by size bin (microns) over a 25-minute
nebulization period with use of 1.6-µm PSL microspheres and the described
protocol. ..................................................................................................... 47
Figure 12. Example schematic of configuration setup and equipment locations for
zone-within-zone expedient isolation. ............................................................. 51
Figure 13. Example schematic of LEV positioning and equipment locations for a
ventilated headboard expedient isolation configuration. .................................... 53
Figure 14. Photograph of ventilated headboard configuration as constructed for field
research at the INTEGRIS Baptist Medical Center, in Oklahoma City, OK. ............ 55
Figure 15. Schematic of zone-within-zone expedient isolation configuration at the
VA Medical Center in Oklahoma City. .............................................................. 62

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