High-flow nasal cannula for hypoxia in the post-anesthetic recovery unit: A systematic review and meta-analysis

Table 1 Characteristics of included studies

Ref.	Country	N (C/I)	RoB	Surgery	Population	Intervention	Comparator	Primary outcome
Ansari et al[11]	Iran	31/28	SC	Thoracic	All comer	HFNC for 24 hours	NC or FM	6-minute walk at POD2
Brainard et al[16]	United States	26/18	High	Thoracic	Admitted to ICU	HFNC for 48 hours	NC or FM	Composite incidence of reintubation, hypoxemia, NIV
Burra et al[17]	India	30/30	High	Cardiac	All comer	HFNC for 4 hours	NC	pH, PaO2, PaCO2 at 1, 2, 4 hours
Chen et al[4]	China	99/98	Low	Laparoscopic	Age > 65	No description	NC	Incidence of hypoxemia until PACU discharge
Corley et al[12]	Australia	74/81	SC	Cardiac	BMI > 30	HFNC for 8 hours	NC or FM	Atelectasis on POD1
El-Nori et al[13]	Egypt	90/90	SC	Thoracic	All comer	HNFC for 48 hours	NC or FM	Incidence of hypoxemia in hospital
Ferrando et al[5]	Spain	74/81	Low	Bariatric	BMI > 35	HFNC for 3 hours	Venturi	Incidence of hypoxemia at 3 hours
Fogagnolo et al[18]	Italy	58/58	High	Thoracic	ASA 1, 2, BMI < 35	HFNC for 24 hours	NC or FM	Diaphragmatic dysfunction at 24 hours
Frassanito et al[6]	Italy	41/42	Low	Gynecologic	BMI < 35	HFNC for 2 hours	Venturi	PF ratio at 2 hours
Fulton et al[14]	United States	25/25	SC	Bariatric	All comer	HFNC for 6 hours	FM	End expiratory lung impedance at 1 hour
Futier et al[7]	France	112/108	Low	Abdominal, thoracic	At risk for PPC	HFNC until 8AM POD1	NC or FM	Hypoxemia at 1 hour
Li et al[19]	China	30/30	High	Orthopedic	Age > 65	HFNC for 1 hour	FM	pH, PaO2, PaCO2 at 1 hour
Mishra et al[20]	India	30/30	High	Non-thoracic	SaO2 < 90	HFNC for 2 hours	Venturi	PF ratio at 2 hours
Parke et al[21]	New Zealand	171/169	High	Cardiac	All comer	HFNC until 9AM POD2	NC or FM	SpO2/FiO2 > 445 at day 3
Pennisi et al[15]	Italy	48/47	SC	Thoracic	All comer	HFNC until 9AM POD2	Venturi	PF ratio < 300 during first 4 days
Rosén et al[8]	Sweden	15/19	Low	Bariatric	BMI > 35	HFNC for 1 hour	NC	PaO2 at 1 hour
Sahin et al[22]	Turkey	50/50	High	Cardiac	BMI > 30	No description	FM	Not clear
Shiho et al[9]	Japan	35/35	Low	Cardiac	No lung disease	HFNC for 1 hour	Venturi	PaO2 at 1 hour
Soliman et al[23]	Egypt	40/40	High	Abdominal	No lung disease, BMI < 35	HFNC for 6 hours	FM	Incidence of PPC during first 5 days
Sun et al[24]	China	39/39	High	Abdominal	ASA 1, 2, BMI < 30	HFNC while in PACU	NC	Atelectasis
Tatuishi et al[25]	Japan	76/72	High	Cardiac	All comer	HFNC for 18 hours	FM	Lung volume reduction
Theologou et al[26]	United Kingdom	33/66	High	Cardiac	PF ratio < 200 after SBT	HFNC until wean or failure	Venturi	Treatment failure
Vourc'h et al[27]	France	43/47	High	Cardiac	SpO2 < 96% on 50% venturi	HFNC for 48 hours	NRB	PF ratio at 1 and 24 hours
Yu et al[28]	China	54/56	High	Thoracic	At risk for PPC	No description	NC or FM	Incidence of hypoxemia during 72 hours
Zochios et al[10]	United Kingdom	45/49	Low	Cardiac	COPD, Asthma, BMI > 35	HFNC for 24 hours	NC or FM	Hospital LOS

C/I: Number of patients in control/number of interventions; RoB: Risk of bias; SC: Some concerns; HFNC: High flow nasal cannula; NC: Nasal cannula; FM: Face mask; POD: Postoperative day; PF: Arterial oxygen pressure to inspired oxygen fraction; SBT: Spontaneous breathing trial; SpO₂: Peripheral oxygen saturation; BMI: Body mass index; COPD: Chronic obstructive pulmonary disease; PPC: Postoperative pulmonary complication; PACU: Post-anesthesia care unit; NRB: Non-rebreather mask; LOS: Length of stay; ASA: American Society of Anesthesiologists; PaO₂: Partial pressure of arterial oxygen; PaCO₂: Partial pressure of arterial carbon dioxide; ICU: Intensive care unit; POD1: Postoperative day 1.

Table 2 Summary of findings with certainty of evidence

Outcomes	Anticipated absolute effects		Number of participants(studies)	Certainty of the evidence (GRADE)
	Risk with conventional oxygen therapy	Risk with high flow nasal cannula (95%CI)
Reintubation	2.8%	OR = 0.93 (0.36-2.38)	1693 (13)	Moderate
Therapy escalation	11.3%	OR = 0.64 (0.31-1.32)	1190 (8)	Moderate
Mortality	1.2%	OR = 0.71 (0.18-2.78)	1172 (8)	Moderate
Atelectasis	29.7%	OR = 0.33 (0.18-9.59)	628 (6)	Low
Hypoxemia	34.6%	OR = 0.42 (0.21-0.83)	1276 (11)	Moderate
Postoperative pulmonary complications	43.7%	OR = 0.68 (0.33-1.40)	645 (6)	Low
Hospital length of stay	Mean of 7.7 days with range 2 to 12 days	MD = 0.58 less (-1.17 to 0.01)	1877 (16)	Moderate
ICU length of stay	Mean of 2.6 days with range 1 to 7 days	MD = 0.02 less (-0.19 to 0.15)	1880 (14)	Moderate
pH	Mean of 7.37 with range 7.34 to 7.41	MD = 0.0002 more (-0.01 to 0.01)	423 (4)	Low
PaO2	Mean of 115.1 with range 87.0 to 158.5	MD = 43.0 more (-15.7 to 101.7)	767 (9)	Low
PaCO2	Mean of 39.9 with range 34.7 to 44.1	MD = 1.1 less (-2.6 to 0.4)	831 (10)	Low
PF ratio	Mean of 222.4 with range 46 to 355.5	MD = 33.4 more (-7.99 to 74.8)	447 (6)	Low
RR	Mean of 19 with range 14 to 22	MD = 1.4 less (-3.0 to 0.3)	343 (4)	Low
SpO2	Mean of 98.8 with range 96.8 to 99.7	MD = 0.84 more (-0.61 to 2.23)	344 (3)	Very low
HR	Mean of 85.6 with range 68 to 105.7	MD = 4.6 less (-8.6 to -0.6)	504 (5)	Low
Discomfort	Mean of 4.1 with range 1.5 to 7.3	MD = 0.7 less (-2.3 to 0.9)	1000 (6)	Low

PaO₂: Partial pressure of arterial oxygen; PaCO₂: Partial pressure of arterial carbon dioxide; ICU: Intensive care unit; POD1: Postoperative day 1; PF: PaO₂/FiO₂ ratio; RR: Respiratory rate; SpO₂: Oxygen saturation; HR: Heart rate; CI: Confidence interval; OR: Odds ratio; MD: Mean difference.