Aerosol protection using modified N95 respirator during upper gastrointestinal endoscopy: a randomized controlled trial.

Background/aims: The coronavirus disease 2019 pandemic has affected the worldwide practice of upper gastrointestinal endoscopy. Here we designed a modified N95 respirator with a channel for endoscope insertion and evaluated its efficacy in upper gastrointestinal endoscopy.

Methods: Thirty patients scheduled for upper gastrointestinal endoscopy were randomized into the modified N95 (n=15) or control (n=15) group. The mask was placed on the patient after anesthesia administration and particles were counted every minute before (baseline) and during the procedure by a TSI AeroTrak particle counter (9306-04; TSI Inc.) and categorized by size (0.3, 0.5, 1, 3, 5, and 10 µm). Differences in particle counts between time points were recorded.

Results: During the procedure, the modified N95 group displayed significantly smaller overall particle sizes than the control group (median [interquartile range], 231 [54-385] vs. 579 [213-1,379]×103/m3; p=0.056). However, the intervention group had a significant decrease in 0.3-µm particles (68 [-25-185] vs. 242 [72-588]×103/m3; p=0.045). No adverse events occurred in either group. The device did not cause any inconvenience to the endoscopists or patients.

Conclusions: This modified N95 respirator reduced the number of particles, especially 0.3-µm particles, generated during upper gastrointestinal endoscopy.