Grant: CIHR Fellowship

Each year 65,000 to 90,000 Canadians become critically ill and need a life-support device called a mechanical ventilator to help them breathe. The mechanical ventilator rhythmically inflates the lung by forcing oxygen into the lungs through a breathing tube in the trachea. In the acute stage of the disease, the mechanical ventilator does most of the breathing for these patients but very soon, as the patient recovers and resumes his/her own breathing, the ventilator needs to work in sync with the patient: the patient makes an effort to breathe, the ventilator detects the effort and delivers support synchronized with the patient's effort. In many cases, however, there is a lack of synchrony between patient and ventilator (patient-ventilator dyssynchrony), which can make the patient uncomfortable, damage the respiratory muscles and the lungs and increase the risk patients will remain on the ventilator for a longer time. Reverse triggering is one of the most frequent types of patient-ventilator dyssynchrony that was only recently identified. It is seen as a patient breathing effort that is triggered after the mechanical ventilator inflates the patient's lungs as if the insufflation from the ventilator stimulated the patient to start breathing. Reverse triggering can be good or bad for patients depending on its characteristics. If during reverse triggering the patient's effort is small, it can preserve respiratory muscles size and strength. On the other hand, if during reverse triggering the effort is too big and very dyssynchronous, it can injure the lungs and the respiratory muscles (as when we get muscle pain because we make too much effort lifting weights). There is no evidence on how to care for patients with reverse triggering. I aim to understand how the parameters set on the mechanical ventilator influence the occurrence and characteristics of reverse triggering so I can use this information to develop strategies to improve the care provided to these patients.