Physiological variables
Wearing an N95 respirator for 4-hour shift was associated with a
significant decrease in PH [7.35mmHg (7.32,7.37) at baseline vs.
7.34mmHg (7.32,7.35) at 4 hours, P=0.02] and PvO2[23.2 mmHg (18.2,34.5) at baseline vs. 18.6 mmHg (14.6, 23.8) at 4
hours, P<0.001]. The change in PCO2[49.5mmHg (44.9, 53.1) at baseline vs. 50.5mmHg (47.1, 56.9) at 4
hours, P=0.22] or bicarbonate [26.2mEq/L (25.3, 28.6) at baseline
vs. 26.6mEq/L (24.5, 28.7) at 4 hours, P=0.53)] did not reach
statistical significance. Results are summarized in Figure 1. There was
no significant change in HR or oxygen saturation. Median
EtCO2 under normal unmasked conditions and at 4 hours
was 32.5mmHg (29.8, 35) vs. 38.5mmHg (34, 41), respectively
(p<0.0001).