Aerosol and droplet generation in upper and lower GI endoscopy: whole procedure and event-based analysis

Background and Aims: Aerosol-generating procedures have become an important healthcare issue during the coronavirus disease 2019 (COVID-19) pandemic because the severe acute respiratory syndrome coronavirus 2 virus can be transmitted through aerosols. We aimed to characterize aerosol and droplet generation in GI endoscopy, where there is little evidence. Methods: This prospective observational study included 36 patients undergoing routine peroral gastroscopy (POG), 11 undergoing transnasal endoscopy (TNE), and 48 undergoing lower GI (LGI) endoscopy. Particle counters took measurements near the appropriate orifice (2 models were used with diameter ranges of.3-25 mmand 20-3000 mm). Quantitative analysis was performed by recording specific events and subtracting background particles. Results: POG produced 1.96 times the level of background particles (P <.001) and TNE produced 2.00 times (P <.001), but a direct comparison showed POG produced 2.00 times more particles than TNE. LGI procedures produced significant particle counts (P <.001) with 2.4 times greater production per procedure than POG but only.63 times production per minute. Events that were significant relative to the room background particle count were POG, with throat spray (150.0 times, P <.001), esophageal extubation (37.5 times, P <.001), and coughing or gagging (25.8 times, P <.01); TNE, with nasal spray (40.1 times, P <.001), nasal extubation (32.0 times, P <.01), and coughing or gagging (20.0, P <.01); and LGI procedures, with rectal intubation (9.9 times, P <.05), rectal extubation (27.2 times, P <.01), application of abdominal pressure (9.6 times, P <.05), and rectal insufflation or retroflexion (7.7 times, P <.01). These all produced particle counts larger than or comparable with volitional cough. Conclusions: GI endoscopy performed through the mouth, nose, or rectum generates significant quantities of aerosols and droplets. Because the infectivity of procedures is not established, we therefore suggest adequate personal protective equipment is used for all GI endoscopy where there is a high population prevalence of COVID19. Avoiding throat and nasal spray would significantly reduce particles generated from upper GI procedures.

Automated summary

This study found that significant quantities of aerosols and droplets are generated during GI endoscopy, particularly with the use of throat and nasal sprays. Adequate personal protective equipment should be used for GI endoscopy in areas with a high prevalence of COVID-19.