Predictors of HFNC Failure in Patients With AHRF Using Diaphragm Ultrasound

Ultrasound of the diaphragm is an easily reproducible bedside tool that provides a non-invasive measurement of inspiratory muscle function and respiratory efficiency. The diaphragmatic thickness correlates with the strength and muscle shortening and is reflective of its contribution to the respiratory workload. Diaphragm thickening fraction (DTF) has been shown to be predictive of extubation failure in ventilated patients. However, whether measurements of DTF are predictive of high flow nasal cannula (HFNC) outcomes in patients with acute hypoxemic respiratory failure (AHRF) remains unknown. The objective of this study is to identify predictors of HFNC failure by diaphragm ultrasound and to compare its performance with the well-established ROX index.