The use of Ventilator Parameters in the Prediction of Development and Outcome of Acute Respiratory Distress Syndrome in Postoperative Patients

Abstract Background: To investigate the usefulness of ventilator parameters in the prediction of development and outcome of acute respiratory distress syndrome (ARDS) in postoperative patients with esophageal or lung cancer on admission to the surgical intensive care unit (SICU). Methods: A total of 32 post-operative patients with lung or esophageal cancer from SICU in a tertiary medical center were retrospectively analyzed. The study patients was divided into ARDS group (n = 21) and non-ARDS group (n = 11). ARDS group were the post-operative patients who developed ARDS after lung or esophageal cancer surgery. The ventilator variables were analyzed in this study. Principal component analysis (PCA) was performed to reduce the correlated ventilator variables to a small set of variables. By using the PCA selection method, top three ventilator variables with large coefficients can be considered as sensitive variables and were included in the analysis model based on the rule of 10 events per variable. Firth logistic regression with selective stepwise elimination procedure was performed to identify the most important predictors of morbidity and mortality in patients with ARDS. The ventilator parameters including rapid shallow breath index during mechanical ventilation (RSBIv), rate pressure product of ventilation (RPPv), rate pressure volume index (RPVI), mechanical work (MW), and inspiration to expiration time ratio (IER) were analyzed in this studyResults: The newly defined parameter MW/IER was the most important predictors for the development of ARDS, and both RPPv and RPVI were the significant predictors of mortality in patients with ARDS.Conclusion: Some ventilator parameters can be derived from ventilator readings and be used to predict the development and outcome of ARDS in mechanically ventilated patients on admission to the SICU, such as RPPv, RPVI and MW/IER defined in this study.