Inspiratory muscle strength and post-liver transplantation outcomes: safety of measurement in the ICU ‒ an observational study.

OBJECTIVE: Assess respiratory muscle strength and hemodynamic responses in the early postoperative period after Liver Transplantation (LT) and to analyze their associations with clinical outcomes. PATIENTS AND METHODS: A prospective and observational study included adult LT recipients admitted to the Intensive Care Unit (ICU) of the Clinical Hospital of the University of Campinas. Inspiratory muscle strength was assessed during the first three postoperative days using a digital Manovacuometer and POWERbreathe® device. Hemodynamic and respiratory parameters were continuously monitored. Statistical analyses included repeated-measures ANOVA, Wilcoxon tests, correlation analyses (p < 0.05), linear mixed models for respiratory variables, and multiple linear regression to examine the directionality of associations. RESULTS: Sample consisted of 35 patients, with a median age of 59-years [IQR: 52.0-68.0] and a predominance of males (n = 26; 74.3%). The MELD mean was 18.1±7.6, SAPS3 score of 44.7±11.2, and SOFA score of 9.2±3.1, MIP increased significantly between postoperative days 1 and 3 (37.5 [32.8-53.8] vs. 49.0 [40.0-72.0] cmH2O, p = 0.035). The S-Index showed significant negative correlations with both surgery duration (r_s = -0.52, p = 0.009) and ICU length of stay (r = -0.42, p = 0.015). No clinically relevant hemodynamic changes occurred during tests; however, there was a main effect of Time for MAP (4.079, 204.0) = 6.765, p < 0.0001) and RR (2.030, 101.5) = 3.628, p = 0.0295). CONCLUSIONS: LT patients exhibit early postoperative improvement in inspiratory muscle strength, with both assessment methods proving safe. Higher dynamic inspiratory strength is associated with shorter ICU stay and surgical duration, supporting the inclusion of routine respiratory muscle monitoring in postoperative physiotherapy protocols.