COVID-19 aerosol box as protection from droplet and aerosol contaminations in healthcare workers performing airway intubation: a randomised cross-over simulation study

Abstract

BackgroundConcerns over high transmission risk of SARS-CoV-2 have led to innovation and usage of an aerosol box to protect healthcare workers during airway intubation in patients with COVID-19. Its efficacy as a barrier protection in addition to the use of a standard personal protective equipment (PPE) is not fully known. We performed a simulated study to investigate the relationship between aerosol box usage during intubation and contaminations on healthcare workers pre-doffing and post-doffing of PPE.MethodsThis was a randomised cross-over study conducted between 9 April to 5 May 2020 in the ED of University Malaya Medical Centre. Postgraduate Emergency Medicine trainees performed video laryngoscope-assisted intubation on an airway manikin with and without an aerosol box in a random order. Contamination was simulated by nebulised Glo Germ. Primary outcome was number of contaminated front and back body regions pre-doffing and post-doffing of PPE of the intubator and assistant. Secondary outcomes were intubation time, Cormack-Lehane score, number of intubation attempts and participants’ feedback.ResultsThirty-six trainees completed the study interventions. The number of contaminated front and back body regions pre-doffing of PPE was significantly higher without the aerosol box (all p values<0.001). However, there was no significant difference in the number of contaminations post-doffing of PPE between using and not using the aerosol box, with a median contamination of zero. Intubation time was longer with the aerosol box (42.5 s vs 35.5 s, p<0.001). Cormack-Lehane scores were similar with and without the aerosol box. First-pass intubation success rate was 94.4% and 100% with and without the aerosol box, respectively. More participants reported reduced mobility and visibility when intubating with the aerosol box.ConclusionsAn aerosol box may significantly reduce exposure to contaminations but with increased intubation time and reduced operator’s mobility and visibility. Furthermore, the difference in degree of contamination between using and not using an aerosol box could be offset by proper doffing of PPE.

Prioritising intubator safety in a pandemic: the details matter

“…9 10 Any benefit can be offset by the use of proper PPE. 11 Additionally, a recent investigation into the practicality of these devices found decreased first pass success, damage to PPE, delays in intubation, increased provider discomfort 12 while checklists have a strong record of efficiency and success, particularly in acute care medicine. [13][14][15] Our institution had approximately 1 week of lead time prior to the surge.…”

Aerosol boxes decrease aerosol exposure only in depressurized rooms during aerosol-generating procedures in a simulation study

“…Several studies have shown that an aerosol box can effectively prevent aerosol dispersion [ 2 , 3 ], whereas other studies have not [ 4 ]. Azhar et al showed that an aerosol box significantly reduced the contaminant exposure level but increased tracheal intubation time and reduced operator mobility and visibility in a simulation study [ 3 ]. One review article showed that enclosure barriers for airway management should be avoided until adequate evidence is gathered [ 4 ].…”

ORi™: a new indicator of oxygenation

“…In addition, owing to the recent outbreak of coronavirus disease 2019 (COVID-19), RSI has been recommended to prevent the infection of anesthesiologists during intubation [30,31]. Furthermore, the use of aerosol boxes for the prevention of COVID-19 infection makes intubation difficult [32][33][34]. Thus, aerosol boxes may increase intubation times and therefore increase the risk of hypoxia in patients [32].…”