Open-label, phase II study of routine high-flow nasal oxygen therapy in cardiac surgical patients

Br J Anaesth. 2013 Dec;111(6):925-31. doi: 10.1093/bja/aet262. Epub 2013 Aug 6.


Background: Respiratory complications after cardiac surgery increase morbidity, mortality, and length of stay. Studies suggest that routine delivery of positive airway pressure after extubation may be beneficial. We sought to determine whether the routine administration of nasal high-flow oxygen therapy (NHF) improves pulmonary function after cardiac surgery.

Methods: A pragmatic randomized controlled trial; participants received either NHF (45 litre min(-1)) or usual care from extubation to Day 2 after surgery. The primary outcome was number of patients with / ratio ≥445 on Day 3 after surgery. The secondary outcomes included atelectasis score on chest X-ray; spirometry; intensive care and hospital length of stay; mortality on Day 28; oxygenation indices; escalation of respiratory support; and patient comfort.

Results: We randomized 340 patients over 14 months. The number of patients with a / ratio of ≥445 on Day 3 was 78 (46.4%) in the NHF group vs 72 (42.4%) standard care [odds ratio (OR) 1.18, 95% confidence interval (CI) 0.77-1.81, P=0.45]. was reduced at both 4 h post-extubation and at 9 a.m. on Day 1 in the NHF group (5.3 vs 5.4 kPa, P=0.03 and 5.1 vs 5.3 kPa, P=0.03, respectively). Escalation in respiratory support at any time in the study occurred in 47 patients (27.8%) allocated to NHF compared with 77 (45%) standard care (OR 0.47, 95% CI 0.29-0.7, P=0.001).

Conclusions: Routine use of NHF did not increase / ratio on Day 3 but did reduce the requirement for escalation of respiratory support.

Trial registration: Australia New Zealand Clinical Trials Registry (ACTRN12610000973011).

Keywords: clinical trial; intensive care; oxygen, therapy; surgery, cardiovascular.

Publication types

  • Clinical Trial, Phase II
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Intranasal
  • Adult
  • Aged
  • Aged, 80 and over
  • Cardiac Surgical Procedures / adverse effects*
  • Critical Care / methods
  • Female
  • Humans
  • Length of Stay / statistics & numerical data
  • Male
  • Middle Aged
  • Oxygen / blood
  • Oxygen Inhalation Therapy / methods*
  • Postoperative Care / methods*
  • Prospective Studies
  • Pulmonary Atelectasis / etiology
  • Pulmonary Atelectasis / prevention & control
  • Respiration Disorders / etiology
  • Respiration Disorders / prevention & control*
  • Respiration, Artificial / methods
  • Treatment Outcome
  • Young Adult


  • Oxygen