Muscle wasting in icu trauma patients: quantitative and qualitative changes

Methods Fifteen ICU patients were studied on day 1 and on day 20 after trauma and compared with 15 anorexic patients with severe malnutrition (BMI < 17) volunteering to participate to the study. Muscle mass was evaluated by ultrasound scan, a recently validated method with several advantages: it is accurate, non-invasive, inexpensive, easily repeatable, easy to perform at bedside and apt to detect both qualitative and quantitative changes of the muscle. In all patients, we studied the rectus femuris (RF) and anterior tibialis (AT) muscles, considering (a) the anterior-posterior diameter, (b) the lateral diameter, (c) the sectional area and (d) the muscle echogenicity according to Heckmatt’s score. Results Our trauma patients were 12 males and 3 females; age was 53 (range 43-61), length of ICU stay 35 days (23-50), days on mechanical ventilation 22 (12-36), injury severity score 34 (27-50), BMI 27.5 (23.1-29.4). The anorexic patients were all female: age 21.5 (17-30), BMI 14.9 (13.2-16.65). From day 1 to day 20 after trauma, the muscle mass decreased significantly, reaching the values observed in the anorexic patients: the anterior-posterior diameter of both RF and AT decreased significantly (p < 0.008 and p < 0.001, respectively); the area of RF decreased by 26.1% (16.1 % 36.3%, p < 0.001); the area of AT decreased by 37.3% (24.5% 50.2%, p < 0.001), reaching a value not dissimilar from anorexic patients (p = 0.18). On day 1 after trauma, muscle echogenicity of both RF and TA was higher than in anorexic patients (p < 0.001), suggesting very early inflammatory changes. The muscle echogenicity was higher on day 20 if compared to day 1, both in RF (p < 0.005) and in AT (p < 0.004), suggesting further abnormalities of muscle structure which cannot be explained by malnutrition alone.