Introduction: There are few data on determinants of long-term outcomes among lung transplant (LTx) patients who require readmission to Intensive Care Unit (ICU).
Objectives: Our aim was to describe the variables associated with one-year mortality in LTx recipients who require readmission to ICU beyond the postoperative period.
Methods: Single-center observacional retrospective analysis of a prospectively assessed cohort of LTx patients who were readmitted to ICU over 6-year period (2011-2016). We have included those LTx patients who required readmission beyond 30 days after transplantation. Patient were followed up to one year after ICU readmission. Demographic data, transplantation-related aspects, and ICU-related variables were collected. Data were expressed as mean (standard deviation), median (interquertile range) or frequency (percentage). Differences between categorical variables were assessed by chi-square or Fisher exact test when necessary.Continuous variables were compared using the Student t test or Mann-Whitney test, as appropriate. To determine which variables were independently associated whith one-year mortality, a backward stepwise logistic regression analysis was performed. Variables with p<0.1 in the univariate analysis were introduced intro the multivariate model. Continuous variables were categorized for this analysis using the observed mean in the overall cohort. A two-sided p value of 0.05 or less was considered statistically significant.
Results: During the study period 342 LTx were performed and 84 LTx recipients requiered ICU readmission, with a total of 100 episodes of ICU readmissions. Patients had a mean age of 53 (12) years old and the mean APACHE II score was 16 (6). The main reason for ICU admission was respiratory failure (70% of the readmissions) and the main respiratory failure etiology was lower respiratory tract infection (59.6% of the respiratory failure episodies). Fifty-four (64.3%) patients died during the follow-up period. APACHE II,SOFA at ICU readmission, need for mechanical ventilation (MV) during their course in the ICU, previous lower respiratory tract infection (LRTI), presence of chronic lung allograft dysfunction (CLAD) and FEV1(1%) reported value prior ICU readmission were included in the multivariate logistic regression analysis. The model showed an association between previous LRTI (OR 17.71 (95%CI 3.52 - 89.15); p<0.001), presence of CLAD (OR 5.46 (95%CI 1.34-22.25),p=0.018), and need for MV during their course in ICU (OR 17.97 (95%CI 4.85-66.64);p<0.001). In this sense, patients who had been diagnosed of LRTI and CLAD prior their ICU readmission and who need MV during their course in the ICU had a predicted probability of one-year mortality of 97%.
Conclusion: LTx patients who require ICU readmission present a high-risk of death during the subsequent year after their readmission. Previous LRTI and CLAD as well as need for MV during ICU stay are independent predictors of one-year mortality.