evaluate the impact of the type of anaesthesia (total intravenous anaesthesia (TIVA)/sevoflurane anaesthesia) for colorectal surgery on the muscle function and mass

Ultrasonographic muscle assessment is standardised in the assessment of muscle according to the SARCUS (Sarcopenia through UltraSound) working group recommendations. Rectus femoris muscle will be evaluated at 50% distance between the anterior superior iliac spine and the superior pole of the patella, in a lying position with knees in 10°, for muscle thickness and muscle cross-sectional area (CSA). Three measurements will be taken for each data point, and the average value will be used for further analysis. The biceps brachii muscle will be evaluated at 50% distance acromioclavicular joint and the elbow crease, in a supine position. Muscle thickness can be easily defined as the maximal vertical distance between the superficial and deep fasciae.

Measuring grip strength is simple and inexpensive. Grip strength will be determined bilaterally. Each measurement will be performed three times on the left and right extremities with 20 seconds intervals between the measurements. The maximum measured value in kilograms will be used for analysis.

The bioimpedance measurements will be performed by a trained operator according to the manufacturer's recommendations. The Body Composition Monitor provides a quantitative measure of lean tissue and fat tissue mass. In contrast to earlier bioimpedance methodologies, the bioimpedance spectroscopy expresses body composition as a three-compartment model, providing overhydration, lean tissue index (LTI), and fat tissue index (FTI), whereby LTI and FTI are the respective tissue masses normalized to height squared.

Correlation between muscle strength and muscle mass using dynamometry and echography and bioimpedance at different time points