Aerosol and Droplet Generation During Intubation and Normal Breathing: A Simulation Study

ABSTRACT

The recent COVID-19 pandemic has made important changes to the everyday practice of anaesthetists. Current research has shown that the virus spreads via respiratory droplets and aerosolisation. The aim of this study was to examine the extent of contact contamination, droplet spread and aerosolisation, which may occur with normal breathing and intubation in a mannequin study. In the first experiment, an Ambu bag was attached to the simulation mannequin’s trachea and an atomiser device was placed into the mannequin’s pharynx. This model simulated normal ventilation as 0.5 ml of luminescent fluid was sprayed through the atomiser. In the second experiment, the mannequin was intubated with a videolaryngoscope while spraying 0.5 ml of luminescent fluid through the atomiser, after which the laryngoscope was removed. The spread of the luminescent aerosol cloud after three full breaths, droplet spread and contact contamination were visualised using ultraviolet light. The extent of spread was evaluated using a 4-point Likert scale (0 to 3) by two observers. Each of the experiments was repeated five times. For the first experiment, aerosol formation, droplet spread and contact contamination were 2.5 (2–3), 1 (0–1), 0 (0–1) points. In the second experiment, aerosol formation, droplet spread and contact contamination were 0.5 (0–1), 1 (0–1), 3 (2–3) points, accordingly. Noticeable contact contamination occurs during laryngoscopy and removal of the laryngoscope, whereas droplet contamination with laryngoscopy and normal breathing is minimal. Normal breathing leads to significant aerosol formation.