Feasibility of Muscle Endurance Testing in Critically Ill Trauma Patients: A Pilot Study

Area of Science:

• Critical Care Medicine
• Neurology
• Rehabilitation Medicine

Background:

• Intensive care unit-acquired weakness (ICUAW) is typically diagnosed using the Medical Research Council sum score (MRC-SS), focusing on muscle strength.
• Patients frequently report fatigability and poor endurance, aspects not captured by traditional strength assessments.

Purpose of the Study:

• To investigate the feasibility of assessing muscle quality and endurance in trauma patients within the intensive care unit (ICU).
• To explore novel methods for a more comprehensive evaluation of muscle function in critically ill patients.

Main Methods:

• Utilized the modified Functional Index-2 (FI2) test to assess muscle endurance.
• Measured maximal voluntary contraction (MVC) and fatigue index (FI) using surface electromyography (sEMG).
• Evaluated muscle echogenicity of rectus femoris (RF) and tibialis anterior (TA) muscles via ultrasound at ICU admission and discharge.

Main Results:

• Surface electromyography (sEMG) revealed significant differences in root mean square (RMS) values of MVC in RF and TA muscles (p < 0.05).
• No significant differences were observed in ultrasound echogenicity, MRC-SS, or fatigue index (FI) between fatigue and non-fatigue groups.
• All patients, except one, had an MRC-SS exceeding 48 points, indicating significant weakness.

Conclusions:

• Muscle strength assessment alone is inadequate for evaluating the functional capacity of ICU patients.
• The modified FI2 test and sEMG monitoring show promise for assessing muscle quality and endurance in critically ill patients, even in complex ICU environments.