SMART
Stimulation of the Phrenic Nerve for Diaphragm Protection in Acute Hypoxemic Respiratory Failure Management
Study Investigators
Dr. Peter Reardon (peter.reardon@uhnresearch.ca)
Dr. Ewan Goligher (ext. 6810, ewan.goligher@uhn.ca)
Study Contact
Dr. Peter Reardon (peter.reardon@uhnresearch.ca)
Study Summary
A clinical trial using temporary transvenous phrenic nerve stimulation (PNS) in patients with acute hypoxemic respiratory failure to preserve diaphragm activity and facilitate lung and diaphragm protective ventilation.
Study Population
Mechanically ventilated patients with acute hypoxemic respiratory failure (P/F ratio < 300 mm Hg).
Study Objectives
To establish whether PNS can achieve and maintain safe diaphragm activity
To characterize the physiologic effects of PNS on gas exchange and the distribution of ventilation
Study Interventions
Patients will be randomized to the intervention (insertion of temporary transvenous PNS) or control groups. Patients will be monitored using esophageal manometry, diaphragm electrical activity, diaphragm ultrasound, and electrical impedance tomography. PNS will be applied as needed for up to 7 days.
Why it Matters
Diaphragm dysfunction is very common in the ICU (up to 84% of patients) and is associated with increased length of stay, prolonged duration of mechanical ventilation, and high mortality. Deep sedation, passive modes of ventilation, and neuromuscular blockade used to facilitate lung protection contribute to diaphragm atrophy and dysfunction.
Temporary transvenous PNS is a novel technique that may be uniquely situated to safely activate the diaphragm while maintaining lung-protective ventilation in patients with acute hypoxemic respiratory failure. In ICU patients with ARDS where clinicians are unable to achieve safe spontaneous breathing, preservation of diaphragm function with temporary transvenous PNS could potentially prevent disuse atrophy and improve clinical outcomes for patients.