Relevant studies for nasal high flow (NHF) use in post-extubated patients following surgery

 Corley et al. [5]Prospective interventional study20 patients post-cardiac surgery with ARF under SOT and then NHFCompared with SOT, NHF increased mean Paw by 3.0 cmH2O, expiratory lung volume by 25.6% and tidal volume by 10.5%. Patients with higher BMI had larger increases in end-expiratory lung volume
 Parke et al. [25]Prospective randomised comparative study56 postoperative patients with ARF, randomised to NHF or to high-flow face maskSignificantly more NHF patients succeeded with their allocated therapy. Patients in the NHF group tended to need NIV less frequently than the high-flow face mask group and had significantly fewer desaturations
 Parke et al. [45]Pragmatic, open-label randomised controlled trial340 post-cardiac surgery patients randomised to NHF or SOT after extubationNo differences in SpO2/FiO2 ratio at day 3 or in-hospital and ICU length of stay and mortality at day 28 were observed between the two study groups. NHF reduced the requirement for escalation of respiratory support
No benefit
 Corley et al. [46]Randomised controlled trial155 patients post-cardiac surgery with BMI ≥30 kg·m−2 randomised to NHF or SOTNo difference was seen between groups in atelectasis scores on day 1 or 5, in mean PaO2/FiO2 ratio or respiratory rate in the first 24 h post-extubation and the length of ICU stay
 Stéphan et al. [52]Multicentre, randomised, unblinded noninferiority trialBiPAP or NHF in 830 cardiothoracic patients who developed ARF after extubation or with pre-existing risk factors for post-extubation ARFNHF was non-inferior to BiPAP in treatment failure, defined as re-intubation for mechanical ventilation, switch to the other study treatment or premature study treatment discontinuation. No significant differences were found in ICU mortality
 Ansari et al. [53]Randomised, controlled, blinded study59 post-elective lung resection surgery patients randomised to NHF or SOTSimilar results were observed in the difference between pre-operative and postoperative 6-min walk test and spirometry between the two study groups. Length of hospital stay was significantly lower in the NHF group
 Futier et al. [54]Multicentre, randomised controlled trial220 post-abdominal surgery patients randomised to NHF or SOTNo differences for postoperative hypoxaemia, pulmonary complications or length of hospital stay were found between the two groups studied

ARF: acute respiratory failure; SOT: standard oxygen treatment; Paw: airway pressure; BMI: body mass index; NIV: noninvasive ventilation; SpO2: arterial oxygen saturation measured by pulse oximetry; FiO2: inspiratory oxygen fraction; ICU: intensive care unit; BiPAP: bi-level positive airway pressure.