Reduced Effective Oxygen Delivery and Ventilation with a Surgical Facemask Placed under Compared to over an Oxygen Mask: A Comparative Study

Table 1

Table of measured FiO₂, FeO₂, EtCO₂, and respiratory rate with a surgical facemask only, an O₂ mask only, a surgical facemask over an O₂ mask, and a surgical facemask under an O₂ mask. Values are reported at mean ± standard deviation.

	FiO2 (%)	FeO2 (%)	EtCO2 (mmHg)	RR (bpm)
Surgical facemask	19.7±2.6	18.6±1.2	24.9±8.6	13.1±3.2
O2 mask	36.3±10.2	46.01±5.2	23.3±7.8	14.8±3.1
Surgical facemask over an O2 mask	35.7±10.7	49.9±6.3	23.5±7.6	13.9±4.9
Surgical facemask under an O2 mask	34.8±6.5	27.9±1.7	28.3±8.5	14.2± 2.8