We study the effects of mechanical ventilation on diaphragm structure and function, and the impact of those changes on outcomes for patients with acute respiratory failure. Diaphragm atrophy and dysfunction are common in mechanically ventilated patients, and are related to diaphragm inactivity, or excessive loading during ventilation. This ventilator induced diaphragm dysfunction delays recovery and prevents patients from being able to breathe without assistance from the ventilator.

Monitoring diaphragm activity during mechanical ventilation is challenging and often requires invasive methods. However, point-of-care ultrasound offers a non-invasive and repeatable approach to visualize and measure diaphragm thickness and function, including changes in structure like atrophy. This protocol provides best practice guidelines for obtaining measures of diaphragm structure and function in healthy and critically ill populations.

In mechanically ventilated critical care patients, changes in diaphragm thickness from baseline are associated with diaphragm weakness and failure to wean from mechanical ventilation. Targeting optimal respiratory effort through therapeutic strategies such as respiratory effort targeted sedation and phrenic nerve stimulation may be able to mitigate ventilator induced diaphragm dysfunction and facilitate lung and diaphragm protective ventilation. The effect of these therapeutic strategies on diaphragm structure and function has yet to be evaluated.