Respiratory risk score for the prediction of 3-month mortality and prolonged ventilation after liver transplantation

Abstract

Survival of critically ill patients is significantly affected by prolonged ventilation. The goal of this study was the development of a respiratory risk score (RRS) for the prediction of 3-month mortality and prolonged ventilation after liver transplantation (LT). Two hundred fifty-four consecutive LT patients from a single center were retrospectively randomized into a training group for model design and a validation group. A receiver operating characteristic (ROC) curve analysis was used to test sensitivity and specificity. The accuracy of the predictions was assessed with the Brier score, and the model calibration was assessed with the Hosmer-Lemeshow test. Cutoff values were determined with the best Youden index. The RRS was calculated in the first 24 hours as follows: (laboratory Model for End-Stage Liver Disease score > 30 5 2.36 points) 1 (fresh frozen plasma > 13.5 U 5 2.70 points) 1 (partial pressure of arterial oxygen/fraction of inspired oxygen ratio < 200 mm Hg 5 2.23 points) 1 (packed red blood cells > 10.5 U 5 3.50 points) 1 (preoperative mechanical ventilation 5 3.87 points) 1 (preoperative dialysis 5 2.83 points) 1 (donor steatosis hepatis > 40% 5 2.95 points). The RSS demonstrated high predictive accuracy, good model calibration, and c statistics > 0.7 in the training and validation groups. The RSS was able to predict 3-month mortality [cutoff 5 6.64, area under the (ROC) curve (AUROC) 5 0.794] and prolonged ventilation (cutoff 5 3.69, AUROC 5 0.798) with sensitivities of 69% and 81%, specificities of 83% and 73%, and overall model correctness of 76% and 77%, respectively. In conclusion, this study provides the first prognostic model for the prediction of 3-month mortality and prolonged ventilation after LT with high sensitivity and specificity and good model accuracy. The application of the RRS to an external cohort would be desirable for its further validation and introduction as a clinical tool for intensive care resource planning and prognostic decision making. Prolonged mechanical ventilation is known to have a significant negative impact on the survival of critically ill patients. 1,2 After liver transplantation (LT), the survival of patients requiring prolonged mechanical ventilation has been shown to be significantly inferior (5-year survival: 65.1% for patients with prolonged mechanical ventilation versus 84.4% for patient who were immediately extubated). 3 A primary diagnosis of acute liver failure, retransplantation, the intraoperative transfusion of more than 15 fresh frozen plasma (FFP) concentrates, mechanical ventilation before LT, a partial pressure of arterial oxygen (PaO 2 )/fraction of inspired oxygen (FiO 2 ) ratio less than 300 mm Hg, and the trend of GOT and GPT in the first 24 hours have been shown to be linked to a prolonged duration of mechanical ventilation after LT. 3,4 Abbreviations: AUROC, area under the receiver operating characteristic curve; CI, confidence interval; FFP, fresh frozen plasma; FiO 2 , fraction of inspired oxygen; HR, hazard ratio; ICU, intensive care...

Tracheostomy Post Liver Transplant: Predictors, Complications, and Outcomes

“…Their findings demonstrated that the respiratory risk score (RRS) could indeed be useful to discriminate between patients with and without post-LT respiratory failure. While the RRS includes many previously identified variables associated with post-LT respiratory failure, it does not appear to utilize any objective findings of nutritional status [ 5 ]. Further, many of the included variables may not be available unless the patient is already in the intensive care unit.…”

“…Of note, a scoring system to calculate the risk of respiratory failure after liver transplantation was recently proposed. This scoring system defines respiratory failure as patients requiring >7.5 days on a respirator, and it takes into account many of the previously identified clinical factors to calculate risk [ 5 ]. However, preoperative pulmonary function testing (PFT) and objective measures of wasting and frailty were not included in the scoring system.…”

Extravascular Lung Water and Pulmonary Vascular Permeability Index Measured at the End of Surgery Are Independent Predictors of Prolonged Mechanical Ventilation in Patients Undergoing Liver Transplantation

“…Several preoperative and intraoperative factors that prolong the length of MV after OLT have been described, including preoperative respiratory status, severity and cause of liver disease, and excessive fluid and/or blood administration. [14][15][16][17][18][19] We found no relationship between these preoperative and intraoperative variables and the incidence of serious postoperative complications. However, these risk factors may still have affected the time to tracheal extubation because PMV was defined as a need for MV for >48 hours.…”

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“…8 Using literature definitions of early and late tracheostomy, 5,9,10 we then categorized patients according to the timing of tracheostomy as early (≤ 3 days after transplant) or late (> 3 days). All tracheostomies were performed using a dilatational technique with bronchoscopic assistance.…”

“…This RRS can predict on the first postoperative day if a critically ill LT patient will require PMV. 8 We hypothesized that, in patients with a high RRS, early tracheostomy would reduce the duration of mechanical ventilation.…”