Switches in non-invasive respiratory support strategies during acute hypoxemic respiratory failure: Need to monitoring from a retrospective observational study.

Objective: To explore combined non-invasive-respiratory-support (NIRS) patterns, reasons for NIRS switching, and their potential impact on clinical outcomes in acute-hypoxemic-respiratory-failure (AHRF) patients.

Design: Retrospective, single-center observational study.

Setting: Intensive Care Medicine.

Patients: AHRF patients (cardiac origin and respiratory acidosis excluded) underwent combined NIRS therapies such as non-invasive-ventilation (NIV) and High-Flow-Nasal-Cannula (HFNC).

Interventions: Patients were classified based on the first NIRS switch performed (HFNC-to-NIV or NIV-to-HFNC), and further specific NIRS switching strategies (NIV trial-like vs. Non-NIV trial-like and single vs. multiples switches) were independently evaluated.

Main Variables Of Interest: Reasons for switching, NIRS failure and mortality rates.

Results: A total of 63 patients with AHRF were included, receiving combined NIRS, 58.7% classified in the HFNC-to-NIV group and 41.3% in the NIV-to-HFNC group. Reason for switching from HFNC to NIV was AHRF worsening (100%), while from NIV to HFNC was respiratory improvement (76.9%). NIRS failure rates were higher in the HFNC-to-NIV than in NIV-to-HFNC group (81% vs. 35%, p < 0.001). Among HFNC-to-NIV patients, there was no difference in the failure rate between the NIV trial-like and non-NIV trial-like groups (86% vs. 78%, p = 0.575) but the mortality rate was significantly lower in NIV trial-like group (14% vs. 52%, p = 0.02). Among NIV to HFNC patients, NIV failure was lower in the single switch group compared to the multiple switches group (15% vs. 53%, p = 0.039), with a shorter length of stay (5 [2-8] vs. 12 [8-30] days, p = 0.001).

Conclusions: NIRS combination is used in real life and both switches' strategies, HFNC to NIV and NIV to HFNC, are common in AHRF management. Transitioning from HFNC to NIV is suggested as a therapeutic escalation and in this context performance of a NIV-trial could be beneficial. Conversely, switching from NIV to HFNC is suggested as a de-escalation strategy that is deemed safe if there is no NIRS failure.