Table 2.

Variables at baseline and 2 h after HFNC therapy initiation

	HFNC success (n = 51)	HFNC failure (n = 24)	p value
Baseline HR [mean ± SD, bpm]	102 ± 18	116 ± 17	0.001
Baseline RR [mean ± SD, cpm]	25 ± 5	28 ± 6	0.015
Baseline FiO2 [mean ± SD]	0.5 ± 0.2	0.5 ± 0.2	0.641
Baseline SpO2 [mean ± SD, %]	95.0 ± 4.0	93.2 ± 6.1	0.140
Baseline PaO2 [M(P25, P75), mmHg]	70.0 (61.0–84.0)	69.8 (60.4–75.4)	0.222
Baseline PaCO2 [mean ± SD, mmHg]	37.4 ± 7.7	34.2 ± 6.5	0.080
Baseline PF ratio [M(P25, P75)]	142.5 (123.6–188.4)	138.0 (114.5–171.5)	0.214
Baseline lactate [mean ± SD, mmol/l]	2.0 ± 1.2	2.7 ± 1.9	0.044
2 h HR [mean ± SD,bpm]	99 ± 17	113 ± 16	0.001
2 h RR [M(P25, P75),bpm]	21 (19–25)	27 (23–35)	0.001
2 h FiO2 [M(P25, P75)]	0.55 (0.50–0.60)	0.69 (0.60–0.89)	0.001
2 h Flow on HFNC [mean ± SD, L/min]	49.7 ± 7.7	52.1 ± 8.2	0.226
2 h SpO2 [M(P25, P75)]	98.0 (96.0–100.0)	95.0 (89.5–97.8)	0.002
2 h PaO2 [mean ± SD, mmHg]	106.7 ± 41.5	75.3 ± 25.2	0.001
2 h PaCO2 [mean ± SD, mmHg]	35.9 ± 8.4	34.2 ± 6.0	0.386
2 h PF ratio [M(P25, P75)]	178.0 (126.0–251.7)	95.7(68.6–131.7)	0.000
2 h lactate [M(P25, P75), mmol/l]	1.4 (1.0–2.0)	2.3(1.7–3.6)	0.001

Annotation: HR, heart rate; RR, respiratory rate; FiO₂, fraction of inspiration O₂; SpO₂,saturation of pulse oxygen ; PaO₂, arterial oxygen partial pressure; PaCO₂, arterial carbon dioxide partial pressure; PF ratio, PaO₂/FiO₂; cpm, counts per minute; bpm, beats per minute; P₂₅, 25th percentile; P₇₅, 75th percentile; HFNC, high-flow nasal cannula