Figure 1. Variable Importance of the Candidate Characteristics in RSF Model.

In this figure, the VIMP was validated by the bootstrapping method with 1000 repetitions and shown as a mean with 95% CI. The top 15 features were included in the final RSF model.

Abbreviations: BMI, body mass index; ECMO, extracorporeal membrane oxygenation; FEV1, forced expiratory volume in 1 second; FEV1 percentage, percentage of predicted forced expiratory volume in 1-second value; FVC, forced vital capacity; FVC percentage, percentage of predicted forced vital capacity value; ICU, intensive care unit; MRBI, multidrug-resistant bacterial infection; Pao₂/Fio₂, arterial oxygen tension/inspired oxygen fraction; RSF, random survival forests; VIMP, variable importance; 6MWT, 6-minute walking test; 72 h PGD3, grade 3 primary graft dysfunction at 72h.