Prospective ultrasonographic evaluation of femoral and vastus intermedius muscles as predictors of ICU-acquired weakness in critically ill patients.

Abstract

Purpose: Intensive care unit-acquired weakness (ICU-AW) is associated with poor functional outcomes and increased healthcare costs. This study aimed to evaluate the diagnostic performance of muscular ultrasound (MUS) measurements in predicting ICU-AW and identify potential predictors.

Methods: Forty-three surgical and medical ICU patients underwent serial MUS measurements of the femoral cross-sectional area (Fcsa) and femoral + vastus intermedius thickness (F + VIth) on days 1, 3 and 5 post-ICU admission. Patients were categorized as having ICU-AW (Medical Research Council (MRC) sum score < 48 at discharge) or not. Univariate and multivariate logistic regression analyses were performed to identify predictors of ICU-AW. The diagnostic performance of MUS measurements was assessed via receiver operating characteristic (ROC) curves. Clinical outcomes (ICU length of stay, ventilator days, extubation failure) were compared between the groups.

Results: Patients with ICU-AW (n = 12, 28%) showed a significant reduction in the Fcsa from Day 1 to Day 5 (p < 0.001). Univariate analysis revealed significant associations between ICU-AW and the Apache II score (OR 1.12, p = 0.03), SOFA score (OR 1.32, p = 0.008), and Day 1 F + VIth score (OR 0.23, p = 0.05). Multivariate analysis confirmed a significant association with the SOFA score (OR 1.35, p = 0.04) and a trend toward an F + VIth score of Day 1 (OR 0.12, p = 0.09). The day 1 Fcsa and F + VIth demonstrated moderate predictive capabilities for ICU-AW (ROC-AUC values of 0.72 and 0.82, respectively). ICU-AW patients experienced longer ICU stays, more ventilator days, and higher extubation failure rates.

Conclusion: Preexisting low muscle mass, combined with a high SOFA score, may be a stronger predictor of ICU-acquired weakness than the degree of subsequent muscle loss.