This study is designed to characterize the changes in diaphragm structure, function and biology during bridging to lung transplant by mechanical ventilation or extracorporeal life support.
Mechanical ventilation has been linked to diaphragm injury and dysfunction. During mechanical ventilation, the amount of breathing work done by the diaphragm is unpredictable: the diaphragm could be completely rested, or it could be overworked. Either of these possibilities may cause injury to the diaphragm. Patients with an injured and dysfunctional diaphragm have greater difficulty weaning from mechanical ventilation - they become too weak to breathe. However, little is known about the relationship between changes in the diaphragm and the histological (structure of cells and tissue) basis of these changes. The investigators have developed a new technique employing beside ultrasound to measure diaphragm thickness. This allows them to observe changes in diaphragm muscle structure and function. The goal of the study is to determine whether different forms of respiratory support (mechanical ventilation vs extracorporeal life support) lead to different degrees of diaphragm injury and to compare changes in the diaphragm seen on ultrasound to changes in the diaphragm tissues under a microscope. This will help the investigators to confirm the best way to avoid diaphragm injury and to understanding the meaning of diaphragm ultrasound images.
Study Type
OBSERVATIONAL
Enrollment
40
Mechanical ventilation or extracorporeal life support
Toronto General Hospital
Toronto, Canada
RECRUITINGDifference in diaphragm thickness and thickening fraction in patients using MV and patients using ECLS
Diaphragm thickness and injury score will be tested for an interaction between the bridging modality (MV vs. ECLS) and the duration of exposure to the modality on the degree of diaphragm injury and atrophy
Time frame: Change from baseline diaphragm thickness and thickening fraction at 7 days after lung transplant
Correlate changes in diaphragm thickness and histological features of diaphragm dysfunction
Histological features to be assessed are: myofibril cross-sectional area, muscle fiber type, presence of cellular infiltrates, myofiber necrosis and regeneration, autophagy and fibro-fatty infiltration
Time frame: Assessed immediately after transplantation
Biomarkers for diaphragm dysfunction
Biomarkers to be assessed are: skeletal troponin-I and markers of systemic inflammation (IL-1, IL-6, Tumor Necrosis Factor (TNF)-alpha)
Time frame: Assessed immediately before transplantation
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.