Clinical value of early bedside ultrasound measurement of quadriceps femoris in diagnosis of ICU-acquired weakness

Abstract

Objective: To explore the correlation between quadriceps thickness (thickness of rectus femoris and vastus intermedius), cross-sectional area (cross-sectional area of the rectus femoris) and the strength score of the Medical Research Council (MRC) in critically ill patients, and to explore the changes in the length of hospital stay in the intensive care unit (ICU), and to determine the diagnostic value of muscle changes in the ICU-acquired weakness (ICU-AW). Methods: Patients admitted to the Department of Critical Care Medicine from March to October in 2019 who were expected to stay for more than five days were enrolled in this study. The cross-sectional area of the rectus femoris, the thickness of the rectus femoris, the thickness of the vastus intermedius on the first day of the ICU (D(1)), day 3 (D(3)), and day 5 (D(5)), day 7 (D(7)), out of ICU (D(ICU)), and the MRC muscle strength scores on the day of out of ICU prospectively were collected in all the patients, and the correlation and the regularity of quadriceps changes were analyzed. MRC>48 points on the day of dismiss of ICU were used as the standard for the diagnosis of ICU-AW, and the relationship between muscle changes of the quadriceps and ICU-AW was analyzed. The t test or the Mann-Whitney U test was used for data analysis. Results: A total of 45 patients were included, including 25 males and 20 females, aged (58±10) years. The rectus femoris cross-sectional area, rectus femoris thickness, and vastus intermedius thickness decreased with the length of ICU hospital stay. The cross-sectional area, thickness of the rectus femoris muscle, and the vastus intermedius thickness were positively correlated with the MRC score (r=0.452, 0.411, 0.402, all P<0.05), and the changes were all negatively correlated with the MRC score (r=-0.682, -0.740, -0.734, all P<0.05). On the 3rd day after ICU admission, the best cutoff value of rectus muscle cross-sectional area atrophy rate for discrimination of ICU-AW was 6.0%, with a sensitivity of 66.7% and a specificity of 77.8%; on the 5th day, the best cutoff value of rectus femoris thickness atrophy rate was 14.5%, with a sensitivity of 77.8% and a specificity of 66.7%; on the 7th day, the best cutoff value of vastus intermedius thickness atrophy rate was 19.9%, with a sensitivity of 70.6% and a specificity of 87.5%. Conclusion: Bedside ultrasound measurement of the quadriceps femoris cross-sectional area and thickness has certain diagnostic value for ICU-AW, and can identify patients with ICU-AW early.