Acute physiologic effects of N95 respirator use on gastroenterologists performing simulated colonoscopy

Published:January 23, 2021DOI:

      Background and Aims

      During the severe acute respiratory syndrome coronavirus 2 pandemic, N95 filtering facepiece respirator (FFR) use was required while performing aerosol-generating procedures. We studied the physiologic effects of N95 FFR use in a cohort of gastroenterologists performing simulated colonoscopies.


      Data collection and comparisons included (1) symptoms and change in vital signs in 12 gastroenterologists performing simulated colonoscopy for 60 minutes while wearing a surgical mask (SM) and faceshield (FS); N95 FFR, SM, and FS; and powered air-purifying respirator (PAPR) and (2) respiratory belt plethysmography and continuous electrocardiographic frequency-based heart rate (HR) variability indices including very low frequency power (measures intracardiac sympathetic tone) and low frequency to high frequency ratios (intracardiac sympathetic to vagal ratio) in 11 gastroenterologists performing simulated colonoscopy while wearing an SM (15 minutes), N95 FFR and SM (60 minutes), and SM (15 minutes) in rapid sequence.


      Ten of 12 gastroenterologists (83%) reported symptoms with N95 FFR use, most commonly breathing difficulty, frustration, fatigue, and headache. Nine of these gastroenterologists (75%) had associated significant HR elevation. Respiratory peak to trough measurement showed a significant increase (F(2) = 7.543, P = .004) during the N95 FFR stage, which resolved after removal of the N95 FFR. Although not statistically different, all gastroenterologists showed a decrease in sympathetic to vagal ratios and an increase in intracardiac sympathetic effects in the N95 FFR stage. PAPR use was better tolerated but was associated with headache and elevated HR in 4 gastroenterologists (33%).


      N95 FFR use by gastroenterologists is associated with development of acute physiologic changes and symptoms.

      Graphical abstract


      ECG (electrocardiogram), EtCO2 (end-tidal CO2), FFR (filtering facepiece respirator), FS (faceshield), HR (heart rate), HRV (heart rate variability), PAPR (powered air-purifying respirator), PPE (personal protective equipment), RN (registered nurse), SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), SM (surgical mask), VLF (very low frequency)
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      Linked Article

      • Behind the mask: physiologic effects of facial personal protective equipment during endoscopy
        Gastrointestinal EndoscopyVol. 94Issue 1
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          In December 2019, a cluster of severe pneumonia cases of unknown causes was identified in Wuhan, Hubei, China. In January 2020, a novel coronavirus, SARS-CoV-2, was identified as the causative virus of COVID-19. This highly contagious virus rapidly spread and was declared a global pandemic on March 11, 2020.1,2 Respiratory droplets and aerosols were found to be the primary method of transmission of this potentially lethal virus. A major challenge in controlling the propagation of COVID-19 is its ability to spread from presymptomatic and asymptomatic individuals.
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