Upper limb muscle atrophy associated with in-hospital mortality and physical function impairments in mechanically ventilated critically ill adults: a two-center prospective observational study

Abstract

Background Lower limb muscle atrophy is often observed in critically ill patients. Although upper limb muscles can undergo atrophy, it remains unclear how this atrophy is associated with clinical outcomes. We hypothesized that this atrophy is associated with mortality and impairments in physical function. Methods In this two-center prospective observational study, we included adult patients who were expected to require mechanical ventilation for > 48 h and remain in the intensive care unit (ICU) for > 5 days. We used ultrasound to evaluate the cross-sectional area of the biceps brachii on days 1, 3, 5, and 7 and upon ICU discharge along with assessment of physical functions. The primary outcome was the relationship between muscle atrophy ratio and in-hospital mortality on each measurement day, which was assessed using multivariate analysis. The secondary outcomes were the relationships between upper limb muscle atrophy and Medical Research Council (MRC) score, handgrip strength, ICU Mobility Scale (IMS) score, and Functional Status Score for the ICU (FSS-ICU). Results Sixty-four patients (43 males; aged 70 ± 13 years) were enrolled. The Acute Physiology and Chronic Health Evaluation (APACHE) II score was 27 (22–30), and in-hospital mortality occurred in 21 (33%) patients. The decreased cross-sectional area of the biceps brachii was not associated with in-hospital mortality on day 3 (p = 0.43) but was associated on days 5 (p = 0.01) and 7 (p < 0.01), which was confirmed after adjusting for sex, age, and APACHE II score. In 27 patients in whom physical functions were assessed, the decrease of the cross-sectional area of the biceps brachii was associated with MRC score (r = 0.47, p = 0.01), handgrip strength (r = 0.50, p = 0.01), and FSS-ICU (r = 0.56, p < 0.01), but not with IMS score (r = 0.35, p = 0.07) upon ICU discharge. Conclusions Upper limb muscle atrophy was associated with in-hospital mortality and physical function impairments; thus, it is prudent to monitor it. (321 words) Trial registration UMIN 000031316. Retrospectively registered on 15 February 2018.

Rectus Femoris Muscle Mass Measured by Ultrasound is an Indicator of Whole-Body Muscle Mass at Intensive Care Unit Admission: A Retrospective Study

“…The reliability of measurements was con rmed by another ICU physician. The intraclass and interclass correlation coe cients were 0.96-0.99 and 0.99 for limbs and 0.92 and 0.96 for the diaphragm, respectively, as reported previously [14].…”

“…At the time of data acquisition, written informed consent was obtained from patients or their relatives. One part of this study was published previously [7,14].…”

Rectus Femoris Mmimicking Ultrasound Phantom for Muscle Mass Assessment: Design, Research, and Training Application

“…Acoustic characteristics of phantom material were measured by Sing-around unit and solid measuring cell (UVM-2 and XM-0031, Cho-Onpa Kogyo, Tokyo, Japan) in cross-sectional and longitudinal section. As a result, sound speed was 1432 m/sec, density 0.954 g/cm 3 , attenuation coefficient 0.59 dB/cmMHz, acoustic impedance 1.37 rayl at 25 °C. After the measurement, the material was adjusted to mimic muscle tissue about the ultrasound image and subjective compression feeling.…”

Urinary Titin N-Fragment as a Biomarker of Muscle Atrophy, Intensive Care Unit-Acquired Weakness, and Possible Application for Post-Intensive Care Syndrome

“…After one week of ICU admission, critically ill patients exhibited 13.2–16.9% of muscle atrophy in the upper limbs, and 18.8–20.7% in the lower limbs [ 18 ]. These muscle atrophies are associated with impaired physical function and mortality [ 19 , 20 ].…”