Ultrasound assessment of muscle mass and correlation with clinical outcomes in critically ill patients: a prospective observational study

Abstract

Purpose: Muscular atrophy implies structural and functional alterations related to muscular force production and movement. This condition has been reported to be the main reason for generalized muscle weakness; it reflects the severity of the disease and can have a profound impact on short- and long-term clinical outcomes. The purpose of this study was to determine whether muscle atrophy ultrasound parameters early predict muscle weakness, morbidity, or 28-days mortality.

Methods: This was a prospective, observational single center cohort study. Ultrasound was used to determine the cross-sectional area and muscle thickness of the rectus femoris on the first and third day of ICU stay. The main outcome was the incidence of significant muscle atrophy (≥ 10%).

Results: Ultrasound measurements were made in 31 patients, 58% (18/31) of which showed significant muscle atrophy. The relative loss of muscle mass per day was 1.78 at 5% per day. The presence of muscle atrophy presents increased risk for limb muscle weakness and handgrip weakness. The 28-days mortality rate was similar in both subgroups.

Conclusion: The presence of muscle atrophy presents an increased clinical risk for the development of limb ICUAW and handgrip, although these observations were not statistically significant. The results could be used to plan future studies on this topic.

Keywords: Intensive care units; Morbidity; Mortality; Muscular atrophy; Ultrasonography.

Fig. 1

Patient eligibility flowchart; Source: Prepared by the author. MV mechanical ventilation

Fig. 2

Box plot ultrasound parameters 1 and Days 3 of ICU management; Source: Prepared by the author in GraphPad Prism 6.0. A CSA-RIGHT on days 1 and 3; B MT-RIGHT on days 1 and 3; C CSA-LEFT; D MT-LEFT; (+) Mean Measurements performed at the baseline and 3 days later (72 h). The behavior of the ultrasound variables is reported, the distributions are wide and the average (+ sign) and median values in all the variables show a tendency to decrease when comparing both days. Right and left CSA and right MT at baseline show a symmetric distribution with similar mean and median values. However, a negative asymmetric distribution is confirmed AFTER 72 h. The distribution of the initial measurement tends to be negatively asymmetrical on MT-LEFT, and with a tendency to be positively asymmetrical at 72 h. However, a general decrease in said ultrasound parameter is confirmed when analyzing dispersion

Fig. 3

Muscle Ultrasound of Patients at Baseline and after 72 h. A and B Indicate ultrasounds of different patients, left panel ultrasounds at the baseline and right panel after 72 h—RF Rectus Femoris, VI Vastus Intermedius, VL Vastus Lateralis, VM Vastus Medialis