Table 2.

Demographic table of partial pressure of arterial oxygen, incidence of severe hyperoxemia, fraction of inspired oxygen, and oxygen reserve index before, and 1 h, 2 h, and 3 h after surgical incision.

	SpO2 group (n = 32)	ORi-SpO2 group (n = 30)	Difference (95% CI)	P value
PaO2
Before surgical incision	265.66 ± 53.17	209.23 ± 41.89	56.42 (32.00–80.85)	<.001*
1 h after incision	250.31 ± 57.39	170.07 ± 49.39	80.25 (52.96–107.53)	<.001*
2 h after incision	244.47 ± 48.63	173.73 ± 46.62	70.73 (46.11–95.36)	<.001*
3 h after incision	246.91 ± 53.08	171.06 ± 50.06	75.85 (41.96–109.74)	<.001*
Severe hyperoxemia
Before surgical incision	30 (93.8)	16 (53.3)	40.50 (14.72–63.55)	<.001†
1 h after incision	27 (84.4)	5 (16.7)	67.70 (21.17–84.51)	<.001†
2 h after incision	26 (83.9)	6 (20)	63.90 (20.56–82.43)	<.001†
3 h after incision	19 (86.4)	1 (5.9)	80.50 (1.73–91.39)	<.001†
FiO2
Before surgical incision	50 (50–60)	50 (45–50)	5 (0–10)	<.001‡
1 h after incision	52.5 (50–60)	40 (35–50)	15 (10–15)	<.001‡
2 h after incision	55 (50–60)	42.5 (35–50)	15 (10–15)	<.001‡
3 h after incision	52.5 (50–60)	40 (35–45)	15 (10–20)	<.001‡
ORi
Before surgical incision	0.33 (0.27–0.44)	0.3 (0.27–0.41)	0.03 (0.03–0.11)	.301
1 h after incision	0.32 (0.24–0.67)	0.25 (0.15–0.29)	0.13 (0.04–0.27)	.005‡
2 h after incision	0.42 (0.28–0.65)	0.27 (0.19–0.31)	0.13 (0.04–0.23)	.003‡
3 h after incision	0.49 (0.38–0.65)	0.27 (0.22–0.42)	0.20 (0.06–0.35)	.008‡

Severe hyperoxemia defined by PaO2 ≥ 200.

PaO2 = partial pressure of arterial oxygen, FiO2 = fraction of inspired oxygen, ORi = oxygen reserve index.

^*P < .05, compared with Student t test.

^†P < .05, compared with Pearson’s chi-square test.

^‡P < .05, compared using the Mann–Whitney U test.