Comparing High-Flow Nasal Cannula Therapy and Conventional Oxygen Therapy in Adult Patients Post-Cardiac Surgery: A Systematic Review and Meta-Analysis.

BACKGROUND

Cardiac surgery with cardiopulmonary bypass structurally alters respiratory mechanics and carries a substantial risk of postoperative morbidity. Historically, patients have routinely received conventional oxygen therapy (COT) following extubation. High- flow nasal cannula (HCNC) therapy has emerged as an innovative respiratory support system. By synthesizing all currently available high-quality randomized controlled trials (RCTs), this study aimed to rigorously evaluate the efficacy and safety of HFNC compared to COT, focusing primarily on determining the need for escalation of respiratory support.

METHODOLOGY: A thorough electronic search was carried out in the PubMed, Embase, and Scopus databases from their inception to May 2026. Only RCTs were considered for analysis. A random-effects model was applied to compute pooled estimates and 95% confidence intervals (CIs).

RESULTS

A total of 11 RCTs, comprising 2473 patients, were included in this systematic review and meta-analysis. HFNC had a statistically significant effect on reducing the requirement for escalation of respiratory support (risk ratio [RR] = 0.71; 95% CI, 0.55-0.93; p = 0.01). HFNC had a statistically significant effect on improving the arterial partial pressure of oxygen, as well as forced expiratory volume in 1 second, while also increasing delirium complications (RR = 3.63; 95% CI, 1.80-7.30; p = 0.0003). There were no statistically significant differences between the 2 approaches in the other secondary clinical and resource utilization outcomes, including intubation, overall mortality, hospital length of stay, intensive care unit length of stay, and postoperative atrial fibrillation.

CONCLUSION

In adult patients recovering from cardiac surgery, HFNC therapy improves oxygenation and significantly curtails the need to escalate respiratory support compared to COT. However, these physiologic and intermediate clinical benefits do not translate into reductions in mortality, reintubation rate, or hospital length of stay and may come at the cost of increased postoperative delirium.