Clin Endosc.  2024 May;57(3):335-341. 10.5946/ce.2023.018.

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

• Nampoolsuksan C
• Akaraviputh T
• Methasate A
• Swangsri J
• Trakarnsanga A
• Phalanusitthepha C
• Parakonthun T
• Taweerutchana V
• Srisuworanan N
• Suwatthanarak T
• Tawantanakorn T
• Lohsiriwat V
• Chinswangwatanakul V

• KMID: 2555895
• DOI: http://doi.org/10.5946/ce.2023.018

Abstract

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.

Keyword

Aerosols; COVID-19; Endoscopy; Gastroscopy; N95 respirators

Figure

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  Fig. 1. Illustration of a modified N95 respirator. A standard N95 respirator (3M Aura 1870+ model) was modified as shown. In proportion to the 9.9-mm outer diameter of the gastroscope (GIF-HQ190; Olympus), two intersecting 10.4-mm linear holes were created and fitted to the diameter of the scope. Illustrated by the author.

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  Fig. 2. TSI AeroTrak (9306-04) handheld particle counter (TSI Inc.).

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  Fig. 3. Endoscopic unit setup. The TSI AeroTrak (9306-04; TSI Inc.) handheld particle counter was placed 1 m apart from patient at the same side as the endoscopist, without any blockages, and the endoscope was inserted through the modified N95 respirator. Illustrated by the author.

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