Are Intubation and Extubation Aerosol-Generating Procedures?
Richard T. Ellison, III, MD
Quantitative analysis found that both tracheal intubation and extubation produce fewer aerosols than volitional coughs.
Epidemiologic studies performed during the severe acute respiratory syndrome (SARS) pandemic in 2003 noted an increased risk for transmission of the SARS coronavirus with tracheal intubation. The finding led to designating tracheal intubation and extubation as aerosol-generating procedures (AGPs). Still, the magnitude of aerosol generation with the procedures has not been measured quantitatively. To address this deficiency, British researchers used laser optical scattering equipment to precisely measure aerosol generation in operating theaters with ultraclean, laminar flow ventilation systems during 19 intubations and 14 extubations of patients undergoing orthopedic trauma or neurosurgical emergency operations and during 38 control volitional coughs from a single individual.
Volitional coughs were characterized by a peak aerosol concentration of 1688 particles/L and an average of 134 total particles within 12 seconds at a distance of 0.5 m from the subject’s mouth; most particles had a diameter of <1 µm. At the same distance, tracheal intubations and extubations, respectively, produced average concentrations of 1.4 and 21 particles/L and averages of 7 and 100 total particles within 5 minutes. Four patients coughed after extubation, but these produced approximately one quarter the particles that volitional coughs produced.
The authors acknowledge study limitations in relation to the COVID-19 pandemic, including the small sample size and lack of inclusion of patients with respiratory virus infection or any ability to assess either the infectivity of the generated aerosols or risk for infection to healthcare workers in the environment. However, the findings suggest that designating all tracheal intubations and extubations as AGPs of greater risk than patients’ coughing is inaccurate. Because designating any procedure an AGP has profound implications for both healthcare practices and personal protective equipment use, it seems highly appropriate, and cost-effective for society, that similar quantitative analyses be undertaken to assess the relative risks associated with all procedures now designated as AGPs.
Brown J et al. A quantitative evaluation of aerosol generation during tracheal intubation and extubation. Anaesthesia 2020 Oct 6; [e-pub].
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