Improved Testing and Design of Intubation Boxes During the COVID-19 Pandemic

Turer, David M.; Good, Cameron H.; Schilling, Benjamin K.; Turer, Robert W.; Karlowsky, Nicholas R.; Dvoracek, Lucas A.; Ban, Heng; Chang, Jason S.; Rubin, J. Peter

STUDY OBJECTIVE: Throughout the coronavirus disease 2019 pandemic, many emergency departments have been using passive protective enclosures (“intubation boxes”) during intubation. The effectiveness of these enclosures remains uncertain. METHODS: We tested a commercially available passive protective enclosure representing the most common design and compared this with a modified enclosure that incorporated a vacuum system for active air filtration during simulated intubations and negative-pressure isolation. We evaluated the enclosures by using the same 3 tests air filtration experts use to certify class I biosafety cabinets: visual smoke pattern analysis using neutrally buoyant smoke, aerosol leak testing using a test aerosol that mimics the size of virus-containing particulates, and air velocity measurements. RESULTS: Qualitative evaluation revealed smoke escaping from all passive enclosure openings. Aerosol leak testing demonstrated elevated particle concentrations outside the enclosure during simulated intubations. In contrast, vacuum-filter-equipped enclosures fully contained the visible smoke and test aerosol to standards consistent with class I biosafety cabinet certification. CONCLUSION: Passive enclosures for intubation failed to contain aerosols, but the addition of a vacuum and active air filtration reduced aerosol spread during simulated intubation and patient isolation.