Fluid removal improves muscle performance and weakness in critically ill patients: a pilot study

Area of Science:

• Critical Care Medicine
• Nephrology
• Ultrasound Imaging

Background:

• Fluid overload is common in critically ill patients, potentially leading to muscle edema and intensive care unit-acquired weakness (ICU-AW).
• Continuous renal replacement therapy (CRRT) with ultrafiltration (UF) is used to manage fluid overload by removing excess extracellular fluid.

Purpose of the Study:

• To investigate the association between UF and changes in muscle ultrasound parameters and strength in critically ill patients.
• To evaluate the impact of UF on muscle tissue characteristics and global muscle strength.

Main Methods:

• Prospective enrollment of critically ill patients undergoing CRRT with UF, compared to a control group without UF.
• Muscle ultrasound assessed rectus femoris and vastus intermedius thickness, echogenicity, and subcutaneous tissue.
• Muscle strength evaluated using the Medical Research Council Sum Score (MRC-SS) at CRRT initiation and 36 hours later.

Main Results:

• UF group showed significant decreases in muscle thickness, echogenicity, and subcutaneous tissue thickness.
• Muscle strength (MRC-SS) significantly increased in the UF group.
• UF volume positively correlated with muscle strength and negatively with muscle echogenicity changes; a UF volume ≥ 82 mL/kg predicted higher muscle strength.

Conclusions:

• Ultrafiltration is associated with improvements in muscle ultrasound parameters and strength in critically ill patients.
• Findings suggest a relationship between fluid balance management and muscle health.
• Further research is needed to establish causality.