Table 5.

Performance metrics of each pulse oximeter for detecting hypoxemia (SaO₂^a<90%). The metrics are shown at a 90% SpO₂^b cut-off and for the determined optimal SpO₂ cut-off.

Device		Cut-off, %		AUROCc, mean (95% CI)	Sensitivity, mean (95% CI)		Specificity, mean (95% CI)		PPVd, mean (95% CI)		NPVe, mean (95% CI)		Accuracyf, mean (95% CI)
90% SpO2 (%) cut-off
	Philips MX 450	90.0	N/Ag		0.86 (0.80-0.92)	0.93 (0.87-0.99)		0.96 (0.92-0.99)		0.79 (0.71-0.88)		0.89 (0.84-0.93)
	CheckMe O2+	90.0	N/A		0.87 (0.81-0.93)	0.85 (0.76-0.93)		0.91 (0.86-0.96)		0.80 (0.71-0.88)		0.87 (0.82-0.91)
	WristOx2 3150	90.0	N/A		0.97 (0.93-0.99)	0.80 (0.70-0.89)		0.89 (0.84-0.94)		0.94 (0.87-0.99)		0.91 (0.86-0.95)
	AP-20	90.0	N/A		0.91 (0.85-0.95)	0.89 (0.82-0.96)		0.94 (0.89-0.98)		0.85 (0.76-0.92)		0.90 (0.86-0.94)
Optimal SpO2 (%) cut-off obtained via AUROC analysish
	Philips MX 450	90.7	0.94 (0.90-0.98)		0.97 (0.94-0.99)	0.86 (0.78-0.94)		0.93 (0.88-0.97)		0.94 (0.88-0.99)		0.93 (0.90-0.97)
	CheckMe O2+	89.0	0.92 (0.87-96)		0.78 (0.71-0.85)	0.88 (0.80-0.95)		0.92 (0.86-0.97)		0.70 (0.60-0.79)		0.82 (0.76-0.87)
	WristOx2 3150	88.0	0.94 (0.89-97)		0.88 (0.82-0.94)	0.86 (0.78-0.94)		0.92 (0.87-0.96)		0.81 (0.72-0.89)		0.88 (0.83-0.92)
	AP-20	91.0	0.94 (0.89-98)		0.95 (0.91-0.98)	0.84 (0.75-0.92)		0.91 (0.86-0.96)		0.91 (0.84-0.97)		0.91 (0.87-0.95)

^aSaO₂: arterial blood oxygen saturation.

^bSpO₂: peripheral oxygen saturation.

^cAUROC: area under the receiver operating characteristic.

^dPPV: positive predictive value.

^eNPV: negative predictive value.

^fAccuracy = (True positives + True negatives)/n, where n is the total number of examples.

^gN/A: not applicable.

^hThe optimal SpO₂ cut-off is the best compromise between sensitivity and specificity to detect hypoxemia (SaO₂<90%).