Physiological Effects of Wearing N95 Respirator on Medical Staff During Prolong Work Hours in Covid-19 Departments

Abstract

BackgroundSince 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.MethodsThis 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.ResultsForty-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. ConclusionUsing 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.