Factors contributing to intensive care unit-acquired weakness in patients with acute decompensated heart failure

Background Acute decompensated heart failure (ADHF) is a leading cause of intensive care unit (ICU) admission. However, the occurrence and underlying mechanisms of ICU-acquired weakness (ICU-AW) in ADHF patients remain unclear. Methods A retrospective case-control study was conducted in 122 ADHF patients admitted to the ICU between August 2022 and March 2023. Patients were classified into ICU-AW and non-ICU-AW groups based on the Medical Research Council score. Muscle morphology was assessed daily using ultrasound, and muscle function was evaluated at ICU discharge using the Short Physical Performance Battery and handgrip strength. Predictors of ICU-AW were identified by logistic regression and decision tree analyses. Mediation analysis (PROCESS macro, Model 4) was performed to test whether DM mediated the association between RFT and ICU-AW. Results Older age and poorer cardiac function were associated with longer ICU stays (P<0.01). ICU stay >3 days, at ICU discharge diaphragmatic motion (DM) <12.56 mm and rectus femoris thickness (RFT) <7.89 mm were independent predictors of ICU-AW. The decision tree model improved prediction accuracy from 28% to 71.4%. Mediation analysis showed that DM significantly mediated the association between RFT and ICU-AW (indirect effect = –0.166, 95% CI: –0.589 to –0.006), accounting for 11.5% of the total effect. Conclusions Diaphragmatic motion partially mediates the effect of rectus femoris thickness on ICU-AW in ADHF patients. Early ultrasound assessment of limb and respiratory muscles may aid in early risk stratification and personalized rehabilitation strategies.