BACKGROUND: Numerous barrier devices have recently been developed and rapidly deployed worldwide in an effort to protect healthcare workers (HCWs) from exposure to COVID-19 during high-risk procedures. However, only a few studies have examined their impact on the dispersion of droplets and aerosols, which are both thought to be significant contributors to the spread of COVID-19. METHODS: Two commonly used barrier devices, an intubation box and a clear plastic intubation sheet, were evaluated using a physiologically accurate cough simulator. Aerosols were modeled using a commercially available fog machine and droplets were modeled with fluorescein dye. Both particles were propelled by the cough simulator in a simulated intubation environment. Data was captured by high-speed flash photography and aerosol and droplet dispersion were assessed qualitatively with and without a barrier in place. RESULTS: Droplet contamination after a simulated cough was seemingly contained by both barrier devices. Simulated aerosol escaped the barriers and flowed towards the head of the bed. During barrier removal, simulated aerosol trapped underneath was released and propelled towards the HCW at the head of the bed. Usage of the intubation sheet concentrated droplets onto a smaller area. If no barrier was used, positioning the patient in slight reverse Trendelenburg directed aerosols away from the healthcare worker located at the head of the bed. CONCLUSION: Our observations imply that intubation boxes and sheets may reduce HCW exposure to droplets, but they both may merely redirect aerosolized particles, potentially resulting in increased exposure to aerosols in certain circumstances. Aerosols may remain within the barrier device after a cough and manipulation of the box may release them. Patients should be positioned to facilitate intubation, but slight reverse Trendelenburg may direct infectious aerosols away from the HCW. Novel barrier devices should be used with caution and further validation studies are necessary.
BACKGROUND: Numerous barrier devices have recently been developed and rapidly deployed worldwide in an effort to protect healthcare workers (HCWs) from exposure to COVID-19 during high-risk procedures. However, only a few studies have examined their impact on the dispersion of droplets and aerosols, which are both thought to be significant contributors to the spread of COVID-19. METHODS: Two commonly used barrier devices, an intubation box and a clear plastic intubation sheet, were evaluated using a physiologically accurate cough simulator. Aerosols were modeled using a commercially available fog machine and droplets were modeled with fluorescein dye. Both particles were propelled by the cough simulator in a simulated intubation environment. Data was captured by high-speed flash photography and aerosol and droplet dispersion were assessed qualitatively with and without a barrier in place. RESULTS: Droplet contamination after a simulated cough was seemingly contained by both barrier devices. Simulated aerosol escaped the barriers and flowed towards the head of the bed. During barrier removal, simulated aerosol trapped underneath was released and propelled towards the HCW at the head of the bed. Usage of the intubation sheet concentrated droplets onto a smaller area. If no barrier was used, positioning the patient in slight reverse Trendelenburg directed aerosols away from the healthcare worker located at the head of the bed. CONCLUSION: Our observations imply that intubation boxes and sheets may reduce HCW exposure to droplets, but they both may merely redirect aerosolized particles, potentially resulting in increased exposure to aerosols in certain circumstances. Aerosols may remain within the barrier device after a cough and manipulation of the box may release them. Patients should be positioned to facilitate intubation, but slight reverse Trendelenburg may direct infectious aerosols away from the HCW. Novel barrier devices should be used with caution and further validation studies are necessary.
Authors: William G Lindsley; John D Noti; Francoise M Blachere; Robert E Thewlis; Stephen B Martin; Sreekumar Othumpangat; Bahar Noorbakhsh; William T Goldsmith; Abhishek Vishnu; Jan E Palmer; Karen E Clark; Donald H Beezhold Journal: J Occup Environ Hyg Date: 2015 Impact factor: 2.155