Grant: Canada Postdoctoral Research Award (CPRA) program

Each year, up to 90,000 Canadians are critically ill and require a mechanical ventilator to breathe. While lifesaving, this machine and the immobilization in the intensive care unit (ICU) can quickly weaken the muscles we use to breathe. When these muscles become too weak, patients cannot breathe on their own and remain ventilator dependent, leading to long ICU stay and high risk of complications and death. We still don't fully understand what is happening to the muscles and why - or why some patients recover while others don't. Current tools are either too limited (like standard ultrasound) or too invasive (like muscle biopsies) to study this phenomenon. Theoretically, rehabilitation can help patients rebuild muscle strength and come off the ventilator, but current techniques are difficult to use in ventilated patients - they require awake, participating patients who are fully disconnected from the ventilator. As a result, rehabilitation in ICU patients is rarely used. This project aims to understand what is happening to the muscles but also to change our inability to perform proper rehabilitation. We are developing a new imaging approach called quantitative ultrasound and photoacoustic imaging that can track muscle damage, recovery, and response to rehabilitation at the bedside. This method shows how well blood and oxygen reach the muscle, and whether it's weakening or recovering. Using this imaging approach, I will monitor muscle trajectories and test the impact of a new rehabilitation technique involving neck flexion against resistance - a simple movement that even ventilated patients can perform. This research will help spot early signs of muscle weakness, better tailor rehabilitation, and support patients in breathing on their own. This ultimately will reduce time on the ventilator and improve the survival of ICU patients.