Table 1.
Summary of the most used tools for muscle mass assessment
| Tool | Assessment | Strength | Limitation |
|---|---|---|---|
| Hand grip strength | On the dominant hand measured using a handgrip dynamometer | • Qualitative assessment of strength in ICU patients | • Requires patient to be cooperative |
| • Strong correlation with BIA | |||
| Body mass index (BMI, kg/m2) | LBM estimation | • Low values of BMI may indicate protein-energy malnutrition | • Does not discriminate between the lean (muscle mass) and fat or water body mass |
| • Decreased sensitivity and specificity as a marker of poor nutritional status | |||
| • Direct correlation with mortality | |||
| Muscle biopsy | Provides histological measurement of the muscle fibers, cellular infiltrates | • Gold standard for diagnosis | • Invasive |
| Bio impedence analysis (BIA) | Indirectly estimates muscle mass using electrical resistance | • Non invasive | • Resistance is affected by fluid status, thus BIA could not be accurate in monitor the change of muscle mass |
| • Could be used for whole-body muscle mass assessment at one point | |||
| • Difference among available devices | |||
| Ultrasound (US) | Measurement of the rectus femoris quadriceps muscle, and biceps brachii taken for cross-sectional area (CSA) or thickness | • Easy to use | • Variability in the measurement technique to quantify muscle mass: CSA versus thickness |
| • Risk of underestimation of muscle mass | |||
| • Reliable | • Need of measurement skill to avoid misinterpretation | ||
| • Lack of standard approach | |||
| • Available at bedside | |||
| Computed tomography (CT) | Measurement of skeletal muscle cross-sectional area at the third vertebrae (L3) level and the cross-sectional area of the femoral muscle volume using sagittal direction integration | • Can separate muscle, fat, and other tissues | • Requires transferring patients in the CT scan room and dedicated trained staff |
| • Radiation exposure | |||
| • CT is considered as an accurate and precise method for muscle mass assessment | • Time consuming | ||
| Anthropometry | Body weight in kilograms (kg) trunk length (cm) measured as distance between the right shoulder and a point 5 cm above the right greater trochanter | • Easy to measure | • Underestimation of muscle mass |
| Mid-thigh, knee, and above-ankle circumferences measured on the right side of the body | |||
| The body cell mass (BCM) in kg calculated using the formula: (0.266*height [cm]) + (0.287*leg circumference [cm]) +(0.305 *Dweight [kg]) – (0.406* truck length [cm]) −13.52. Dweight is the difference between ICU and post-ICU | • Non invasive | • Not done routinely | |
| Triceps skinfold thickness measured (in mm) using callipers with the right elbow flex and right hand touching the left shoulder, at the midpoint between the acromion and olecranon process in the posterior surface of the right arm |