Efficacy of an Ambulance Ventilation System in Reducing EMS Worker Exposure to Airborne Particles from a Patient Cough Aerosol Simulator

Details

• Personal Author:
  Blanchere, Francoise M. ; Lindsley, William G. ; Martin SB Jr. ; McClelland, Tia L. ; Mead, Kenneth R. ; Mnatsakanova A ; Neu, Dylan T. ; Noti JD
• Description:
  The protection of emergency medical service (EMS) workers from airborne disease transmission is important during routine transport of patients with infectious respiratory illnesses and would be critical during a pandemic of a disease such as influenza. However, few studies have examined the effectiveness of ambulance ventilation systems at reducing EMS worker exposure to airborne particles (aerosols). In our study, a cough aerosol simulator mimicking a coughing patient with an infectious respiratory illness was placed on a patient cot in an ambulance. The concentration and dispersion of cough aerosol particles were measured for 15 min at locations corresponding to likely positions of an EMS worker treating the patient. Experiments were performed with the patient cot at an angle of 0 degrees (horizontal), 30 degrees, and 60 degrees, and with the ambulance ventilation system set to 0, 5, and 12 air changes/hour (ACH). Our results showed that increasing the air change rate significantly reduced the airborne particle concentration (p < 0.001). Increasing the air change rate from 0 to 5 ACH reduced the mean aerosol concentration by 34% (SD = 19%) overall, while increasing it from 0 to 12 ACH reduced the concentration by 68% (SD = 9%). Changing the cot angle also affected the concentration (p < 0.001), but the effect was more modest, especially at 5 and 12 ACH. Contrary to our expectations, the aerosol concentrations at the different worker positions were not significantly different (p < 0.556). Flow visualization experiments showed that the ventilation system created a recirculation pattern which helped disperse the aerosol particles throughout the compartment, reducing the effectiveness of the system. Our findings indicate that the ambulance ventilation system reduced but did not eliminate worker exposure to infectious aerosol particles. Aerosol exposures were not significantly different at different locations within the compartment, including locations behind and beside the patient. Improved ventilation system designs with smoother and more unidirectional airflows could provide better worker protection. [Description provided by NIOSH]
• Subjects:
  Coal Coal Mining Minerals Mining Occupational Health Safety
• Keywords:
  Aerosol Particles Aerosols Author Keywords: Airborne Disease Transmission Disease Transmission Emergency Medical Services Emergency Medical Services Workers Emergency Vehicle EMS HVAC Infection Control Infection Control Motor Vehicles Simulation Methods Ventilation Systems

  More +
• ISSN:
  1545-9624
• Document Type:
  Text
• Genre:
  Journal Article
• Place as Subject:
  Ohio ; OSHA Region 3 ; OSHA Region 5 ; West Virginia
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  HELD - Health Effects Laboratory Division ; RHD - Respiratory Health Division ; DFSE - Division of Field Studies and Engineering
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Volume:
  16
• Issue:
  12
• NIOSHTIC Number:
  nn:20057709
• Citation:
  J Occup Environ Hyg 2019 Dec; 16(12):804-816
• Contact Point Address:
  William G. Lindsley, National Institute for Occupational Safety and Health, 1000 Frederick Lane, M/S 4020, Morgantown, WV 26508
• Email:
  wlindsley@cdc.gov
• Federal Fiscal Year:
  2020
• NORA Priority Area:
  Healthcare and Social Assistance
• Peer Reviewed:
  True
• Source Full Name:
  Journal of Occupational and Environmental Hygiene
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:a2d0f3fd17abdb28e22af28859d7a93d6346efbf6b01b7fe0c6bb4a5b6fa5fc7b514006719ce6c718d55c25b0c522a3816c5687cfc571ba0a204b63a8cc186b6
• Download URL:
  https://stacks.cdc.gov/view/cdc/214959/cdc_214959_DS1.pdf
• File Type:
  [PDF - 2.35 MB ]