Abstract
Background Transmission of SARS-CoV-2 by bioaerosols is of increasing concern. The enhanced levels of personal protective equipment (PPE) and preventative measures to attenuate viral transmission during aerosol generating procedures (AGPs) are having a huge impact on healthcare provision. There is no quantitative evidence on the number and size of airborne particles produced during AGPs to inform risk assessments.
Methods Real-time, high-resolution environmental monitoring was conducted in ultraclean ventilation operating theatres. Continuous sampling with an optical particle sizer allowed characterization of aerosol generation within the airway management zone during endotracheal intubation and extubation for urgent orthopaedic trauma or neuro-surgery.
Results Aerosol monitoring showed a very low background particle count allowing resolution of the transient airborne particle plume produced by reference volitional coughs (maximum concentration, 1,690±140 particles.L-1,n=38). By comparison, endotracheal intubation including mask ventilation produced negligible quantities of aerosolized particles (maximum concentration, 80±10 L-1,n=14, P<0·001 vs cough). Extubation, particularly when the patient coughed, produced a detectable aerosol plume but with a smaller number of particles (<25%) than a volitional cough.
Conclusions Using a volitional cough as a reference we have been able to produce a relative risk ranking for endotracheal intubation and extubation as potential AGPs. The study does not support the assignation of endotracheal intubation by direct laryngoscopy with manual ventilation as an AGP. Extubation does generate aerosols, particularly if the patient coughs, but these are weaker than a standard reference. These findings indicate the need for a reappraisal of guidance on PPE for AGPs.
Competing Interest Statement
Grant funding for research but no other competing interests.
Clinical Trial
Not a clinical trial
Funding Statement
Project supported by Elizabeth Blackwell Institute with funding from the University of Bristol's alumni and friends. BRB is supported by the Natural Environment Research Council (NE/P018459/1). Neither funder had any role in study design, conduct, analysis or manuscript drafting.
Author Declarations
I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.
Yes
The details of the IRB/oversight body that provided approval or exemption for the research described are given below:
Ethical approval for the study was given by The Faculty of Life Science and Science Research Ethics Committee at University of Bristol (ref: 105203).
All necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived.
Yes
I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).
Yes
I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable.
Yes
Data Availability
The data in the manuscript will be shared with any interested party on reasonable request to the corresponding author.