. 2017 May 30;2017(5):CD010172. doi: 10.1002/14651858.CD010172.pub2

Zochios 2018.

*Study characteristics*
Methods	RCT, parallel‐group design. Single‐centre study
Participants	Total number of randomized participants: 100 Setting: ICU; UK Inclusion criteria: scheduled for CABG; > 18 years of age; ≥ 1 patient‐related risk factor for postoperative pulmonary complications; capable of performing 6MWT Exclusion criteria: contraindications to HFNC; needing CPAP preoperatively; did not meet criteria for extubation by 10 a.m. the day after surgery Baseline characteristics: Intervention group (HFNC): Age, mean (SD): 67.3 (± 9.3 ) years Gender, M/F: 30/19 BMI, mean (SD): 32 (± 5.5) kg/m² APACHE II: not reported PaCO₂, mean (SD): not reported PaO₂/FiO₂, mean (SD): not reported Control group (NIV): Age, mean (SD): 69.1 (± 11.1) years Gender, M/F: 28/11 BMI, mean (SD): 30.2 (± 6.6) kg/m² APACHE II: not reported PaCO₂, mean (SD): not reported PaO₂/FiO₂, mean (SD): not reported
Interventions	Intervention group: Randomized, n = 51; losses, n = 2 (delayed extubation); analysed, n = 49 Details: post‐extubation in the ICU. FiO₂ titrated to SpO₂ ≥ 95% (or 93% for those at risk of hypercapnic respiratory failure). Standard starting flow rate was 30 L/min, adjusted up or down within a range of 20 to 50 L/min with aim of respiratory rate of < 16 breaths/min and patient comfort. HFNO for 24 hours or longer if deemed necessary Control group: Randomized, n = 49; losses, n = 3 (2 delayed extubation; 1 withdrew consent; procedure cancelled); analysed, n = 45 Details: standard oxygen therapy via nasal prongs or soft facemask. FiO₂ titrated to SpO₂ ≥ 95% (or 93% for those at risk of hypercapnic respiratory failure). Oxygen therapy for 24 hours or longer if deemed necessary
Outcomes	Hospital length of stay; ICU length of stay; ICU re‐admission rate; in‐hospital mortality; escalation of respiratory support (unplanned CPAP, NIV or MV); pulmonary function tests; 6MWT; postoperative quality of recovery
Notes	Funding/declarations of interest: funded by AAGBI. Fisher and Paykel Healthcare Ltd provided equipment and were not involved in data collection, analysis, and writing the manuscript. One author has received educational funding, honoraria or travel assistance from CSL Behring, Massimo, Pharmacosmos, Fisher and Paykel, Brightwake Ltd and Vifor Pharma. No other declarations or competing interests declared Study dates: not specified
*Risk of bias*
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated randomization
Allocation concealment (selection bias)	Low risk	Use of a centralised online system
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding was not possible. Although we expected that this would not influence outcome data, we could not be certain of this.
Blinding of outcome assessors (objective outcomes)	Low risk	Blinding of outcome assessors was not described; we did not anticipate that this would influence the assessment of objective outcome measures.
Blinding of outcome assessors (subjective measures)	Low risk	Staff responsible for decisions regarding patient care were blinded to groups.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Few losses
Selective reporting (reporting bias)	High risk	Study was prospectively registered with a clinical trials register (NCT02496923). We noted that mortality was an additional outcome that was not listed in the clinical trials register. All other outcomes were reported as described in the register.
Other bias	Low risk	We identified no other sources of bias.

AAGBI: Association of Anaesthetists of Great Britain and Ireland. AHRF: acute hypoxaemic respiratory failure AIDS: acquired immune deficiency syndrome APACHE II: acute physiology and chronic health evaluation II ASA: American Society of Anesthesiologists BiPAP: bilevel positive airway pressure BMI: body mass index CABG: coronary artery bypass graft CI: confidence interval COPD: chronic obstructive pulmonary disease CPAP: continuous positive airway pressure ECG: electrocardiographic EIT: electrical impedance tomography FiO₂: fraction of inspired oxygen GCS: Glasgow coma score HFFM: high‐flow face mask HFNC: high‐flow nasal cannulae HFNO: high‐flow nasal oxygen ICU: intensive care unit IQR: interquartile range ITT: intention‐to‐treat MAP: mean arterial pressure M/F: male/female MV: mechanical ventilation n: number of participants NC: nasal cannula(e) NIPPV: non‐invasive positive‐pressure ventilation NIV: non‐invasive ventilation NIH: National Institutes of Health NRS: numerical rating scale PaCO₂: carbon dioxide clearance PaO₂: partial pressure of arterial oxygen PEEP: positive end‐expiratory pressure pH: potential of hydrogen SaO₂: oxygen saturation of arterial blood SAPS II: simplified acute physiological score SBP: systolic blood pressure SBT: spontaneous breathing trial SD: standard deviation SOFA: sequential organ failure assessment score SpO₂: oxygen saturation VAS: visual analogue scale VPAP: this is the name of a device 6MWT: six minute walk test