Use of a Negative Pressure Containment Pod Within Ambulance-Workspace During Pandemic Response

Abstract

Emergency medical services (EMS) providers have been some of the most exposed healthcare workers during the COVID-19 pandemic even when wearing personal protective equipment. Pre-hospital environments have a high risk of disease transmission exposing EMS providers to bioaerosols and droplets from infectious patients. Field intubation procedures may be performed causing the generation of bioaerosols thereby, increasing the exposure of EMS workers to pathogens. Additionally, ambulances have a reduced volume compared to a hospital treatment space, often without an air filtration system, and no control mechanism to reduce exposure. The present study evaluated two different filtration systems for reducing aerosol concentrations in the cabin of the ambulance. Concentration measurements were done in an unoccupied research ambulance at NIOSH Cincinnati using a tracer aerosol and optical particle counters. The first system evaluated small portable HEPA filter units within the ambulance compartment after the aerosol generation had occurred. The second one was a containment pod with HEPA filters that was developed and tested based on its ability to isolate and filter aerosols during the intubation procedure while in transport. The HEPA units reduced aerosol concentration by about 1/3rd amount within initial 10 minutes when compared to the natural decay. The containment pod with HEPA filters showed instantaneous containment of generated particle concentrations. Both filtration systems can help reduce aerosol concentrations within the ambulance cabin.