The Combination of APACHE II Score, Neutrophil/lymphocyte Ratio And Expired Tidal Volume Could Better Predict Noninvasive Ventilation Failure In Pneumonia-Induced Mild To Moderate ARDS Patients

Background: To identify the variables easily obtained at the bedside for prediction of failure of noninvasive ventilation (NIV) among pneumonia-induced mild to moderate acute respiratory distress syndrome (ARDS) patients. Methods: : A total of 131 pneumonia-induced mild to moderate ARDS patients were enrolled in this retrospective observational study. Electronic medical records were reviewed to determine whether NIV succeeded or failed for each patients, and we compared the variables between NIV success and failure patients. Multivariate logistic regression analysis were made to identify the independent factors of NIV failure, and we developed an equation based the results of the analysis. Receiver-operating characteristic (ROC) curves were built to assess the efficacy of variables to predict NIV failure. Kaplan-Meier curves for 28-day survival were built to compare the mortality between different groups. Results: 64 (48.9%) patients experienced NIV failure. APACHE II score, neutrophil/lymphocyte ratio (NLR) and expired tidal volume (Vte) were independent factors for predicting NIV failure. The combination value of APACHE II score, NLR and Vte had better efficacy of predicting NIV failure (AUC, 0.9; 95% CI 0.845-0.955) than APACHE II score (AUC, 0.818; 95% CI0.745-0.891), NLR (AUC, 0.839; 95% CI 0.765-0.913) and Vte (AUC, 0.805; 95% CI 0.729-0.881) respectively. The cumulative survival probability within 28 days was lower in patients with combination value>59.17 (P16.5 (P7.22 (P8.96ml/kg (P16.5, NLR>7.22 and Vte>8.96ml/kg may be a useful surrogate for predicting NIV failure among pneumonia-induced ARDS patients, and patients with combination value>59.17 should cautiously monitored during NIV. Further study with a larger sample size is warranted.