Contributing Factors to Acute Respiratory Distress Syndrome after Cardiac Surgery: Role of Mechanical Ventilation-An Observational Prospective Study - Abstract
Objective: Patients undergoing cardiopulmonary by-pass (CPB) often require prolonged mechanical ventilation during the post-operative period. Several observational studies have shown that, in critically ill patients undergoing mechanical ventilation without acute respiratory distress syndrome (ARDS), high tidal volume was associated with the development of ARDS, while the role of mechanical ventilation in the development of ARDS in CPB patients remains unknown. This study hypothesized that injurious mechanical ventilation during the post-operative period of CPB was a risk factor to the development of acute respiratory distress syndrome.
Methods: A prospective observational study was conducted in the cardiac intensive care unit of a University Hospital, in Turin, between December 2010 and December 2012. Any patient admitted to cardiac intensive care unit, following cardiac surgery on CPB was enrolled. No intervention was required. Baseline, operative and post-operative variables were collected from each patient and the development of ARDS over 7 days was recorded. A multivariate logistic regressions analysis was performed to determine independent risk factor for the development of ARDS.
Results: One hundred sixty three patients met inclusion criteria and were enrolled into the study. Twenty patients developed ARDS, on day 3.4±1.0. Multivariate logistic regression analysis identified high tidal volume, respiratory rate (RR), euroSCORE and fresh frozen plasma transfusions (FFP) as risk factors for ARDS.
Conclusions: Injurious mechanical ventilation, characterized by high tidal volume and RR, together with high severity of the peri-operative conditions and transfusions, represent independent risk factors for ARDS in patients following CPB.