Physiological effects of wearing N95 respirator on medical staff during
prolong work hours in Covid-19 departments
Abstract
Objective: Since the emergence of coronavirus disease, health care
professionals in high-risk environments are mandated to wear N95
respirators for prolonged periods. The effect of this prolonged use on
cardio-respiratory variables and gas-exchange is poorly defined. The
objective of the current study was to determine gas exchange
abnormalities and physiological changes among healthcare workers during
a 4-hour emergency department (ED) shift while wearing the N95
respirator. Methods: This was a single-center prospective observational
study that consisted of medical staff working at the Sheba Medical
Center ED. Physiological effects and gas exchange variables were
obtained under normal breathing conditions and after 4-hour shifts while
continuously wearing an N95 respirator. Comparisons of paired
measurements were performed using a non-parametric Wilcoxon
matched-pairs signed-rank test. Results: Forty-one subjects were
included in the study. Prolonged N95 respirator use was associated with
a significant decline in plasma pH [7.35mmHg vs. 7.34mmHg, P=0.02],
PvO2 [23.2 mmHg vs. 18.6 mmHg, P<0.001] and a concurrent
increase in EtCO2 [32.5mmHg vs. 38.5mmHg, p<0.0001]. PvCO2
and bicarbonate levels did not differ. No significant change was
observed for heart rate or oxygen saturation. Conclusion: Using an N95
respirator for prolonged periods by healthcare professionals may provoke
changes in gas exchange. The clinical significance of these changes in
terms of symptoms or longer-term health status is unknown and remains to
be determined. Key Words: N95 Respirator, Physiological effects, SARS
CoV 2.