Diaphragm Structure and Pathobiology in Patients Being Bridged to Lung Transplant
Diaphragm Structure and Pathobiology in Patients Being Bridged to Lung Transplant
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.
Inclusion Criteria (Cases):

 -  Receiving a respiratory support modality as a bridge to lung transplantation

 -  Formally listed for transplantation

 Inclusion Criteria (Control Group 1):

 - Undergoing lung transplantation for either obstructive or restrictive lung disease

 Inclusion Criteria (Control Group 2):

 - Undergoing elective thoracic surgery without any prior history of chronic pulmonary
 parenchymal disease

 Exclusion Criteria (Cases and Controls):

 -  Previously diagnosed with neuromuscular disorder

 -  Received invasive mechanical ventilation for >48 hours in the preceding four weeks

 -  Thoracic cage deformity