Investigational device no longer has Health Canada approval.

ROSETTA is a multi-centre study evaluating the time course of diaphragm thickness and function following exposure to neuromuscular blockade or control in patients with acute respiratory distress. ROSETTA is an ancillary study to the Re-evaluation of Systemic Early Neuromuscular Blockade (ROSE) trial (NCT02509078). It is designed to (1) test the feasibility of a multi-center evaluation of the diaphragm structure and function by ultrasound during mechanical ventilation and (2) determine whether neuromuscular blockade accelerates atrophy and dysfunction of the diaphragm in patients with acute respiratory distress syndrome (ARDS).

A growing body of evidence strongly suggests that mechanical ventilation injures the respiratory muscles, particularly the diaphragm. Due to the deleterious effects of diaphragm inactivity on diaphragm function, there are important concerns about the risk of diaphragm weakness and difficult liberation from mechanical ventilation following neuromuscular blockade. Sonographic measurements of diaphragm thickness provide a potentially useful window for studying diaphragm injury and function during mechanical ventilation.

Patients enrolled in the ROSE trial (randomizing patients with moderate-severe acute respiratory distress syndrome to receive neuromuscular blockade or control for 2 days) will be eligible for participation in this study. Study patients will undergo regular diaphragm ultrasound to assess diaphragm thickness and activity during the first week of the study. Diaphragm function will be assessed by ultrasound on study days 7, 14, 21, and 28.

ROSETTA is designed to:

1. Test the feasibility of a multi-center evaluation of the diaphragm structure and function by ultrasound during mechanical ventilation;
2. Determine whether neuromuscular blockade accelerates atrophy and dysfunction of the diaphragm in patients with acute respiratory distress syndrome; and
3. Evaluate whether patients with greater diaphragm dysfunction exhibit worse functional outcomes compared to patients without diaphragm dysfunction.

Inclusion Criteria:

1. Patients enrolled in the ROSE PETAL trial (adult patients with moderate-severe acute respiratory distress syndrome who have received invasive mechanical ventilation for less than 5 days)

Exclusion Criteria:

1. Patients expected to be extubated within 24 hours of screening for eligibility
2. Patients with a contraindication to chest ultrasonography (chest tubes inserted over right lower chest wall; chest wall trauma)

Patients with moderate to severe acute respiratory distress syndrome (ARDS) who consent to the ROSE trial will be invited to participate in the ROSETTA study.