Aerosol generation during coughing: an observational study

Abstract

Objective Coronavirus disease 2019 has highlighted the lack of knowledge on aerosol exposure during respiratory activity and aerosol-generating procedures. This study sought to determine the aerosol concentrations generated by coughing to better understand, and to set a standard for studying, aerosols generated in medical procedures. Methods Aerosol exposure during coughing was measured in 37 healthy volunteers in the operating theatre with an optical particle sizer, from 40 cm, 70 cm and 100 cm distances. Results Altogether, 306 volitional and 15 involuntary coughs were measured. No differences between groups were observed. Conclusion Many medical procedures are expected to generate aerosols; it is unclear whether they are higher risk than normal respiratory activity. The measured aerosol exposure can be used to determine the risk for significant aerosol generation during medical procedures. Considerable variation of aerosol generation during cough was observed between individuals, but whether cough was volitional or involuntary made no difference to aerosol production.

Risk of Bacterial Exposure to the Anesthesiologist’s Face During Intubation and Extubation

“…Coughing produced the greatest number of aerosol particles among six respiratory activities, including quiet breathing, talking, exercise, shouting, and forced expirations, particularly increasing the particle count 370.8-fold compared with quiet breathing. 16 Recent studies that quantified the amount of aerosol generation during general anesthesia have shown that patient coughing during extubation increased the amount of aerosol generation, [10][11][12] which is consistent with our study result that all positive bacterial exposure belonged to extubation cases with patients coughing, and the CFU count was correlated with the number of coughing episodes. According to previous studies, 9,11,12 endotracheal extubation produces aerosols, but the amount was comparable to or less than that of coughing.…”

“…16 Recent studies that quantified the amount of aerosol generation during general anesthesia have shown that patient coughing during extubation increased the amount of aerosol generation, [10][11][12] which is consistent with our study result that all positive bacterial exposure belonged to extubation cases with patients coughing, and the CFU count was correlated with the number of coughing episodes. According to previous studies, 9,11,12 endotracheal extubation produces aerosols, but the amount was comparable to or less than that of coughing. Therefore, based on our study, coughing during the process of extubation could be considered an important factor in bacterial exposure during this procedure.…”

“…8 In previous studies that quantified aerosol generation during general anesthesia, aerosols were detected during endotracheal extubation; however, the results were conflicting during endotracheal intubation. [9][10][11][12] There have been no studies on bacterial exposure to anesthesiologists' faces during endotracheal intubation, extubation, and airway suction. Therefore, this prospective study aimed to determine bacterial exposure to anesthesiologists' face shields during endotracheal intubation and extubation by comparing pre-and post-procedural samples from face shields.…”

Comparison of aerosol generation between electrocautery and cold dissection tonsillectomy

“…Both the World Health Organization and previous studies have used coughing as the cut-off value for significant aerosol production, which was also used in the current study. 3,[14][15][16][17][18] Thus, the cough measurements presented in Sanmark et al 19 were used to evaluate the level of the risk of infection by comparing the aerosol concentrations measured during the tonsillectomies with cough concentrations. 19 By comparing aerosol generation with coughing during tonsillectomy, it is possible to assess whether the procedure is safer, equivalent to or more dangerous than coughing in terms of aerosol generation.…”

Necrotising otitis externa, epistaxis education and aerosol generation in coughing

“…10 This issue of The Journal has a paper from Helsinki, Finland, in which aerosol production was measured in an operating theatre environment. 11 An intentional cough generated just as much aerosol as an unintentional cough, and there was a great variation of aerosol production between different individuals. The figures produced in this study can be used as a guide to aerosol transmission in this environment.…”