“…All included studies analyzed N95 model FFRs. 4 , 5 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 Additionally, 1 investigation employed FFR P100, 7 another used PFF-3, 20 and 7 also used surgical masks. 5 , 16 , 21 , 22 , 23 , 31 , 41 More than half of the studies included in this review received funding.…”