Bedside ultrasound is a practical measurement tool for assessing muscle mass

OBJECTIVE: To evaluate the intra- and inter-reliability and the ease of measuring the quadriceps muscle thickness using bedside ultrasound. METHODS: This is a prospective, observational study. The assessment of quadriceps muscle thickness was performed at two reference points and was quantified using portable B-mode ultrasound in two healthy volunteers. For standardization of measurements and validation of image collections, the team was trained through theoretical and practical classes, with a 6-hour workload. RESULTS: A total of 112 images were examined by the coach and compared with the trainees. Pearson's correlation analysis found an excellent relationship between the coach and all trainees (R(2) > 0.90). The best association was between the coach and the dietitians (R(2): 0.99; p < 0.001), and the worst association was between the coach and the medical trainees (R(2): 0.92; p < 0.001). In the Bland-Altman comparison, the highest error rate found between coach and trainees was 5.12% (95% confidence interval [CI] 3.64-12.37), and the lowest was 1.01% (95%CI 0.72 - 2.58); the highest bias of the values described was -0.12 ± 0.19, and the lowest was -0.01 ± 0.04. CONCLUSION: The data analyzed showed a good correlation between the measurements made by the coach and trainees, indicating that ultrasound of the quadriceps muscle is a viable and easily applicable tool.