Table 3.

Comparison of Outcome Variables in Study Cohort

Variables	Control Group (n = 87)	LF Group (n = 83)	HF Group (n = 83)	P Value
Hypoxemia (< 95% for >5 s)	24 (27.6)	6 (7.2)	1 (1.2)	< 0.001*
Odds ratio (95% CI)	1.000	0.184 (0.067 to 0.503)	—	0.001†
	1.000	—	0.026 (0.003 to 0.207)	< 0.001†
	—	1.000	0.143 (0.017 to 1.245)	0.078†
Hypoxemia (<95% for > 5 s), PP	24 (27.9)	6 (7.2)	1 (1.2)	< 0.001*
Odds ratio (95% CI)	1.000	0.182 (0.067 to 0.499)	—	< 0.001†
	1.000	—	0.027 (0.004 to 0.216)	< 0.001†
	—	1.000	0.151 (0.017 to 1.307)	0.086†
Hypoxemia (<90% for > 5 s)	4 (4.6)	2 (2.4)	0 (0.0)	0.171‡
Odds ratio (95% CI)	1.000	0.571 (0.096 to 2.674)	—	0.479†
	1.000	—	0.110 (0.001 to 1.067)	0.058†
Minimum Spo2 (%)	94.1 ± 6.2	98.9 ± 2.6	99.3 ± 1.2	< 0.001§
Adjusted mean difference (95% CI)	Ref.	4.802 (3.589 to 6.015)	—	< 0.001∥
	Ref.	—	5.143 (3.931 to 6.355)	< 0.001∥
	—	Ref.	0.341 (–0.885 to 1.568)	0.584∥
Mean ETco2 (mmHg)	35.2 ± 6.41	34.2 ± 6.03	21.57 ± 12.31	< 0.001§
Adjusted mean difference (95% CI)	Ref.	–0.771 (–3.032 to 1.490)	—	0.502∥
	Ref.		–13.395 (–15.755 to –11.035)	< 0.001∥
		Ref.	–12.624 (–15.002 to –10.246)	< 0.001∥
Mean tCO2	39.9 ± 4.21	39.63 ± 4.39	39.34 ± 4.55	0.528§
Patients with rescue intervention	46 (52.9)	9 (10.8)	3 (3.6)	< 0.001*
Odds ratio (95% CI)	1.000	0.101 (0.044 to 0.232)	—	< 0.001†
	1.000	—	0.030 (0.009 to 0.104)	< 0.001†
	—	1.000	0.297 (0.077 to 1.147)	0.078†
Oxygen supplementation/increasing oxygen flow rate or Fio2	45 (51.7)	4 (4.8)	1 (1.2)	< 0.001*
Jaw thrust/head extension	12 (13.8)	7 (8.4)	1 (1.2)	0.009*
oral/nasal airway	0	1 (1.2)	0	0.358*
Assisted ventilation	1 (1.1)	0	0	0.384*
Reducing drug dose	0	0	1 (1.2)	0.358*

Data are presented as mean ± SD and n (%).

^*Chi-square test; †Logistic regression analysis; ‡Fisher exact test; §Kruskal-Wallis test; ∥Linear regression analysis.

ETco₂, end-tidal carbon dioxide; HF, high flow; LF, low flow; PP, per-protocol; tCO₂, transcutaneous CO₂.