No Sustained Benefit of High-Flow Nasal Oxygen After Cardiac Surgery: NOTACS

Why It Matters

The finding challenges the expanding use of HFNOT in postoperative care, showing no clinical or cost benefit over conventional oxygen. Hospitals can redirect resources away from routine HFNOT toward interventions with proven impact on pulmonary outcomes.

Key Takeaways

• NOTACS found no 90‑day outcome difference between HFNOT and standard oxygen
• 1,280 high‑risk cardiac surgery patients had similar respiratory support escalation (~55%)
• Median days alive at home without increased support (DAH90) was zero
• Quality of life scores and 90‑day readmission rates were comparable
• Findings discourage routine prophylactic HFNOT use after cardiac surgery

Pulse Analysis

High‑flow nasal oxygen therapy has been promoted as a way to reduce postoperative pulmonary complications, especially after major cardiac procedures. Early single‑center studies suggested shorter intensive‑care stays and fewer readmissions, prompting many institutions to adopt HFNOT as a prophylactic measure. The NOTACS trial, the largest to date, enrolled patients from 17 centers across three countries, applying a standardized 16‑hour HFNOT protocol immediately after extubation. By measuring days alive and at home without increased respiratory support (DAH90) and incorporating health‑economic analyses, the study provides a more patient‑focused assessment than prior surrogate endpoints.

The trial’s results were unequivocal: HFNOT did not improve DAH90, with both arms achieving a median score of zero, and roughly 55% of patients in each group required escalation of respiratory support. Secondary outcomes—including EuroQol quality‑of‑life scores, Barthel index functional assessments, and 90‑day readmission rates—showed no statistical advantage. These findings suggest that the device itself is not the rate‑limiting factor for recovery; underlying comorbidities such as COPD, obesity, and smoking history dominate outcomes. Consequently, routine blanket application of HFNOT adds equipment costs without delivering measurable benefits, a crucial consideration for value‑based care models.

Looking ahead, researchers argue that a more nuanced, response‑guided approach may still hold promise. Monitoring indices like the ROX score within the first few hours post‑extubation could identify patients who would truly benefit from high‑flow support. Additionally, future trials should capture granular daily data on location and support needs to reduce reporting bias. Until such targeted strategies are validated, clinicians are advised to reserve HFNOT for select cases rather than adopting it as a universal postoperative protocol.