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]. PvCO2and 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.