Respiratory consequences of N95-type Mask usage in pregnant healthcare workers—a controlled clinical study

Tong, Pearl Shuang Ye; Kale, Anita Sugam; Ng, Kailyn; Loke, Amelia Peiwen; Choolani, Mahesh Arjandas; Lim, Chin Leong; Chan, Yiong Huak; Chong, Yap Seng; Tambyah, Paul Anantharajah; Yong, Eu-Leong

During the pre-exercise rest period, breathing through N95-mask materials lowered TV by a mean of 0.15 L compared with controls (95 % CI: −0.23, −0.08; p < 0.001) (Fig. 4a) . TV during both exercise cycles increased rapidly to reach a plateau which was about 50 % higher than that observed at rest, within a minute. However, compared with controls, exercising with N95-masks reduced mean TV by 0.21L (95 % CI: −0.32, −0.10; p < 0.001), a 23 % decrease (Fig. 4a, Table 1 ). Mean BF increased by 35 % during exercise for both control and N95 cycles compared to the rest period, but there was no difference in BF with and without wearing N95-masks (Fig. 4b, Table 1 ). Wearing N95-respirators lowered V E by 25.8 %, a mean difference of 5.55L/min (95 % CI: −7.58, −3.51; p < 0.001) (Fig. 4c , Table 1 ). Significant differences in TV and V E with N95 cycles persisted in the post-exercise rest period (Table 1) . There was a tidal volume reduction of 0.08L (p = 0.02) and minute ventilation reduction of 1.1L/min (p = 0.031).