Evaluating Muscle Mass Changes in Critically Ill Patients: Rehabilitation Outcomes Measured by Ultrasound and Bioelectrical Impedance.

Background/objectives: The loss of muscle mass is common in critically ill patients and is associated with poor prognosis, and efforts have been made to mitigate muscle loss through rehabilitation. This study aimed to evaluate changes in muscle mass in critically ill patients following rehabilitation.

Methods: We enrolled 53 patients expected to stay in the ICU for more than 7 days, dividing them into rehabilitation (15 patients) and no rehabilitation groups (38 patients). Muscle mass was measured using ultrasound and bioelectrical impedance analysis (BIA).

Results: Baseline characteristics and comorbidities showed no statistical differences between the two groups. Initial measurements of muscles showed no significant differences between the groups in rectus femoris thickness, total anterior thigh muscle thickness, cross-sectional area, echogenicity, or in-body skeletal muscle mass at baseline and 7 days. However, at 14 days, significant differences emerged. The rehabilitation group had greater rectus femoris thickness (1.42 cm vs. 0.81 cm, p = 0.007) and total anterior thigh muscle thickness (3.79 cm vs. 2.32 cm, p = 0.007) compared to the no rehabilitation group. Additionally, the rehabilitation group experienced a significantly smaller reduction in rectus femoris cross-sectional area (-4.6% vs. -22.8%, p = 0.021). Although survival rates were higher in the rehabilitation group (73.3% vs. 52.6%), this difference was not statistically significant (p = 0.096).

Conclusions: Our findings suggest that rehabilitation in critically ill patients is associated with a slower rate of muscle loss, particularly in the cross-sectional area of the rectus femoris muscle, which may be beneficial for patient recovery.