Evaluation of muscle loss by ultrasonography in critically ill patients.

Background: Critically ill patients have intense muscle tissue mobilization, and attenuating protein catabolism may contribute to improved outcomes.

Objective: To evaluate short-term muscle loss in critically ill patients.

Methods: In this prospective observational study, we evaluated the thickness of the rectus femoris muscle by ultrasonography in young and older adults of both sexes admitted to a cardiological intensive care unit within 48 h of admission (baseline) and after 7 days. The results were compared and correlated with anthropometric, clinical, and biochemical parameters. The significance level for all statistical analyses was 0.05.

Results: The final sample comprised 88 patients with a mean age of 66.2 ± 11.8 years. There was an average 13.5% reduction in rectus femoris muscle thickness over the study period (P < 0.001), regardless of the thigh circumference maintenance (P = 0.229). This reduction occurred even with improved clinical parameters (C-reactive protein, Simplified Acute Physiology Score) and was greater in patients receiving mechanical ventilation and sedation and in those who died. Regarding nutrition status, malnourished and eutrophic individuals showed greater muscle loss than overweight individuals. There was also an inverse correlation of muscle loss (percentage) with body mass index, arm circumference, and calf circumference (P < 0.05), demonstrating that the lower these anthropometric measurements, the higher the muscle loss obtained by ultrasound.

Conclusion: Ultrasonography assessment detected muscle mass loss in the short-term more sensitively than the anthropometric method. However, it demands caution and further studies demonstrating this analysis.