Assessment of nasal pressure swing predicts respiratory support dependency in patients with hypoxic respiratory failure.

Background: Monitoring is essential in managing acute hypoxemic respiratory failure (AHRF). Nasal pressure swing (P) may predict high-flow nasal oxygen (HFNO) therapy failure and respiratory support dependency. This study investigates P's predictive value for respiratory support needs and clinical outcomes in AHRF patients initially treated with HFNO.

Methods: This post-hoc analysis included 60 AHRF patients treated with HFNO. Respiratory variables, including P, were assessed at baseline and two hours after HFNO initiation. Patients were classified into high (HG) and low (LG) Pnose groups based on a 5.1 cmH2O threshold. The primary outcome was RS-free survival at day 7; HFNO failure, escalation to non-invasive ventilation (NIV) or mechanical ventilation (MV), mortality, and HFNO weaning time were also analyzed. Predictive accuracy of respiratory indices, including P, was evaluated.

Results: Out of the patients enrolled, 35 were in the HG, and 25 in LG group. HG patients showed a lower RS-free survival at day 7 (adjusted HR=0.26, p < 0.0001), and experienced higher failure rates of HFNO (88 % versus 0 %, p < 0.0001), escalation to NIV (84 % versus 0 %, p < 0.0001), endotracheal intubation (36 % versus 0 %, p < 0.0001), and mortality (24 % versus 6 %, p = 0.0001) compared to LG. Accordingly, RS-free days at day 28 were lower in HG (11 days versus 23 days, p < 0.0001). Finally, among the respiratory variables, P resulted independently associated with the primary outcome (OR=0.64 95 %CI [0.42-0.90], p = 0.02).

Conclusions: In patients with AHRF admitted to the ward and treated by HFNO, P is an independent and accurate factor in forecasting the dependency from RS and survival within the first week.