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Safety Precautions and Operating Procedures in an ABSL-4 Laboratory: 3. Aerobiology
Published on: October 3, 2016
Potential airborne pathogen transmission in a hospital with and without surge control ventilation system
Francis J Offermann1, Aaron Eagan2, Aidan C Offermann1
1Indoor Environmental Engineering, San Francisco, CA, USA.
Abstract:
To better understand the transport of airborne particulate matter (PM) in hospital environments when surge control strategies are implemented, tests were conducted in a recently decommissioned hospital during a one-week period. An aerosol was released within a patient room and concentrations measured in the room and hallway with and without surge control ventilation system modifications. The average hallway protection efficiencies were high (>98%) both for the baseline ventilation configuration and when the ventilation system was modified for whole floor negative pressure, indicating very little PM reached the hallway. During entry/exit events through the patient room door into the hallway, the average minimum hallway protection efficiencies were lower during the modified ventilation operation (93-94%) than for the baseline operation (98-99%). These lower hallway protection efficiencies may be explained by the 52% reduction in the outdoor air ventilation being supplied to the hallway during the modified operation mode. This suggests that patient room doors should remain closed to control PM movement into the hallway. In addition, if there is concern about airborne infection transmission, an anteroom may be used to further reduce the transport of particles from the patient rooms to the hallways of the ward.
Insights
Closing patient room doors significantly reduces airborne particulate matter (PM) spread in hospitals. Modified ventilation for surge control lowered hallway protection during door openings, highlighting the importance of closed doors and anterooms for infection control.
Area of Science:
- Environmental Health
- Hospital Ventilation Systems
- Infection Control Engineering
Background:
- Understanding airborne particulate matter (PM) transport is crucial for infection control in healthcare settings.
- Surge control strategies in hospitals can impact ventilation dynamics and contaminant spread.
- Previous research has focused on general ventilation, with less emphasis on PM transport during specific events like door openings under modified conditions.
Purpose of the Study:
- To quantify airborne particulate matter (PM) transport from patient rooms to hallways under different ventilation scenarios.
- To evaluate the effectiveness of surge control ventilation modifications in reducing PM spread.
- To provide evidence-based recommendations for controlling airborne transmission in hospitals.
Main Methods:
- Conducted a one-week study in a decommissioned hospital.
- Released aerosolized particulate matter (PM) in a patient room.
- Measured PM concentrations in the room and adjacent hallway.
- Compared PM transport with baseline ventilation and modified surge control ventilation (whole floor negative pressure).
- Assessed protection efficiency during static conditions and dynamic entry/exit events through the patient room door.
Main Results:
- High average hallway protection efficiencies (>98%) were observed in both baseline and modified ventilation configurations under static conditions.
- During patient room door entry/exit events, hallway protection efficiencies decreased significantly with modified ventilation (93-94%) compared to baseline (98-99%).
- A 52% reduction in outdoor air supply to the hallway during modified ventilation likely contributed to lower protection efficiencies during door openings.
Conclusions:
- Maintaining closed patient room doors is essential for minimizing particulate matter (PM) movement into hospital hallways.
- Modified ventilation strategies for surge control may reduce hallway protection during door openings, emphasizing the need for strict adherence to door closure protocols.
- The implementation of anterooms can provide an additional layer of protection against airborne particle transport from patient rooms to wards.
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