Observational StudyMeasurement of Extravascular Lung Water to Detect and Predict Primary Graft Dysfunction Following Lung Transplant

Primary graft dysfunction (PGD) is the most common cause of early morbidity and mortality following lung transplant and is characterized by acute lung injury and capillary leak leading to an increase in extravascular lung water index (ELWI) and impaired graft function. PGD has many features in common with acute respiratory distress syndrome (ARDS). PGD may be life-threatening and can also lead to impaired long term lung function. In ARDS, a restrictive fluid strategy has been associated with an improvement in lung function and outcomes. Accurate methods of evaluating, quantifying and guiding the hemodynamic / fluid management and limiting the extent of ELWI that accumulates in the setting of PGD are lacking. Using transpulmonary thermodilution to estimate ELWI and the pulmonary permeability index (PPI) represents a novel approach to fluid management, which has been used in patients with ARDS, but to date not in the transplant setting. To determine if these measurements may better guide the management of lung transplant patients, the investigators first wish to establish whether these methods are able to predict the onset of clinical pulmonary edema earlier, whether they correlated with traditional markers of PGD, and whether they may be useful for predicting outcomes.

AIM 1: The investigators will evaluate the correlation between ELWI and current surrogates of pulmonary edema in lung transplant patients with and without Primary Graft Dysfunction (PGD)

AIM 2: The investigators will correlate the use of ELWI and PPI to determine the presence and severity of PGD.

AIM 3: a) The investigators will determine whether early measurements of ELWI and PPI can predict the onset of PGD.

b) Across different strata of PGD, the investigators will determine whether ELWI and PPI have a differential effect on duration of mechanical ventilation.

The results of the study will be used for the following:

1. Provide the rationale for routine monitoring of ELWI to detect PGD if found to be more discriminatory and have a stronger association with outcome compared to the current gold standard.
2. Provide the means of early identification of those as risk of developing PGD in order to guide management decisions or future therapeutic interventions aimed at preventing or treating PGD.
3. Provide the requisite groundwork for a clinical trial comparing the effects of an ELWI-driven protocol versus usual care on ICU outcomes in lung transplant recipients.