AEROSOL AND DROPLET GENERATION IN UPPER AND LOWER GASTROINTESTINAL ENDOSCOPY: WHOLE PROCEDURE AND EVENTBASED ANALYSIS

ABSTRACT

AIM: We aimed to characterise aerosol and droplet generation in gastrointestinal endoscopy. METHODS: This prospective observational study included patients undergoing routine per-oral gastroscopy (POG, n = 36), trans-nasal endoscopy (TNE, n = 11) and lower gastrointestinal (LGI) endoscopy (n = 48). Particle counters took measurements near the appropriate orifice (two models used, diameter ranges 0.3-25 μm and 20-3000 μm). Quantitative analysis was performed by recording specific events and subtracting the background particles. RESULTS: POG produced 2.06x the level of background particles (P < 0.001), and 2.13x the number of particles compared to TNE. LGI procedures produce significant particle counts (P < 0.001), with a rate of 8.8x106/min/m3 compared to 13.0x106/min/m3 for POG. Events significant relative to the room background particle count were POG- throat spray (112.3x, P < 0.01), oesophageal extubation (36.7x, P < 0.001), coughing/gagging (30.7x, P < 0.01);TNE- nasal spray (32.8x, P < 0.01), nasal extubation (25.6x, P < 0.01), coughing/gagging (23.3x, P < 0.01);LGI- rectal intubation (3.5x, P < 0.05), rectal extubation (11.8x, P < 0.01), application of abdominal pressure (4.9x, P < 0.05). These all produced particle counts larger than or comparable to volitional cough. CONCLUSIONS: Gastrointestinal endoscopy performed via the mouth, nose or rectum all generates significant quantities of aerosols and droplets. As the infectivity of procedures is not established, we therefore suggest adequate Personal protective equipment (PPE) is used for all GI endoscopy where there is a high population prevalence of COVID-19. Avoiding throat and nasal spray would significantly reduce particles generated from UGI procedures.