Diaphragm thickening fraction as a predictor of the need for ventilatory support in the emergency department: an observational pilot study.

AIM: Early identification of patients likely to require ventilatory support is a key emergency department priority. Bedside diaphragm ultrasound provides a rapid assessment of respiratory muscle function, and the diaphragm thickening fraction quantifies diaphragmatic contraction during tidal breathing.

MATERIAL AND

METHODS

In this prospective observational pilot study, adults with acute respiratory failure in a single emergency department underwent diaphragm ultrasound within 6 hours of presentation. The primary outcome was initiation of non-invasive ventilation or invasive mechanical ventilation from emergency department presentation through hospitalization.

RESULTS

Among 56 patients, 22 (39%) required ventilatory support. Diaphragm thickening fraction was lower in those requiring support (median 20.93% vs 29.8%; p = 0.006). Higher diaphragm thickening fraction was associated with lower odds of ventilatory support (OR 0.93 per 1% increase, 95% CI 0.88-0.98; p = 0.008). Discriminative ability was moderate (AUC 0.72, 95% CI 0.58-0.87), and the optimal cutoff was 22.1% (sensitivity 59%, specificity 71%).

CONCLUSIONS

Early emergency department assessment of diaphragm thickening fraction may help identify patients at increased risk of requiring ventilatory support.