Diaphragm excursion as a predictor of noninvasive ventilation failure in the emergency department: A prospective...

Early identification of noninvasive ventilation (NIV) failure is essential to prevent clinical deterioration and guide timely escalation of care in acute and critical care settings.

This study aimed to evaluate the diagnostic accuracy of right diaphragm excursion measured by point-of-care ultrasound (POCUS) in predicting NIV failure and to identify associated predictors.

We conducted a prospective diagnostic accuracy study in the emergency department of a tertiary care hospital between January and October 2024. Adult patients (≥18 years) with acute respiratory failure requiring NIV were included. Exclusion criteria included neuromuscular disease, hemodynamic instability, cardiac or respiratory arrest, or drug-induced respiratory depression. Prior to NIV initiation, right diaphragm excursion was assessed via M-mode POCUS in the subcostal view by five trained emergency medicine residents. NIV failure was defined as the need for intubation due to clinical deterioration or intolerance.

Among 77 patients, 21 (27.3 %) experienced NIV failure. Diaphragm excursion <1.4 cm predicted NIV failure with an area under the curve (AUC) of 0.86 (95 % CI: 0.76-0.93), sensitivity 85.7 %, specificity 85.7 %, positive predictive value 66.7 %, negative predictive value 94.0 %, and accuracy 84.4 %. Right diaphragm excursion <1.4 cm was independently associated with NIV failure (OR: 42.12; 95 % CI: 6.79-261.12), along with older age (OR: 1.15; 95 % CI: 1.04-1.27) and lower base excess (OR: 0.85; 95 % CI: 0.74-0.98).

Diaphragm excursion showed high diagnostic accuracy and independently predicted NIV failure. Its integration into early assessment in acute care may support informed decisions and improve outcomes.