Inflammation and altered metabolism impede efficacy of functional electrical stimulation in critically ill patients

Assessing the oral and suprahyoid muscles in healthy adults using muscle ultrasound to inform the swallowing process: a proof-of-concept study

The oral and suprahyoid muscles are responsible for movements of swallowing. Our study aimed to determine the reproducibility of static and dynamic measurements of these muscles using bedside ultrasound equipment. Forty healthy participants were recruited prospectively. Primary outcomes were evaluation of mass measurements of the anterior bellies of the digastric, mylohyoid, geniohyoid and tongue in B-mode ultrasound. Secondary outcomes were evaluation of geniohyoid muscle layer thickness and function using M-mode. Muscle mass measurements demonstrated little within-participant variability. Coefficient of Variance (CoV) across muscles were: anterior belly digastric (5.0%), mylohyoid (8.7%), geniohyoid (5.0%) and tongue (3.2%). A relationship between sex (r2 = 0.131 p = 0.022) was demonstrated for the geniohyoid muscle, with males having higher transverse Cross Sectional Area (CSA) (14.3 ± 3.6 mm vs. 11.9 ± 2.5 mm, p = 0.002). Tongue size was correlated with weight (r2 = 0.356, p = 0.001), height (r2 = 0.156, p = 0.012) and sex (r2 = 0.196, p = 0.004). Resting thickness of the geniohyoid muscle layer changed with increasing bolus sizes (f = 3.898, p = 0.026). Velocity increased with bolus size (p =  < 0.001, F = 8.974). However swallow time and slope distance did not, potentially influenced by higher coefficients of variation. Oral and suprahyoid muscle mass are easily assessed using bedside ultrasound. Ultrasound may provide new information about muscle mass and function during swallowing.

Ultrasound-derived rates of muscle wasting in the intensive care unit and in the post-intensive care ward for patients with critical illness: Post hoc analysis of an international, multicentre randomised controlled trial of early rehabilitation

BACKGROUND AND AIMS

Muscle wasting results in weakness for patients with critical illness. We aim to explore ultrasound-derived rates of change in skeletal muscle in the intensive care unit (ICU) and following discharge to the post-ICU ward.

DESIGN

Post hoc analysis of a multicentre randomised controlled trial of functional-electrical stimulated cycling, recumbent cycling, and usual care delivered in intensive care.

METHOD

Participants underwent ultrasound assessment of rectus femoris at ICU admission, weekly in the ICU, upon awakening, ICU discharge, and hospital discharge. The primary outcome was rate of change in rectus femoris cross-sectional area (ΔRFCSA) in mm2/day in the ICU (enrolment to ICU discharge) and in the post-ICU ward (ICU discharge to hospital discharge). Secondary outcomes included rate of change in echo intensity (ΔEI), standard deviation of echo intensity (ΔEISD), and the intervention effect on ultrasound measures. Echo intensity is a quantitative assessment of muscle quality. Elevated echo intensity may indicate fluid infiltration, adipose tissue, and reduced muscle quality.

RESULTS

154 participants were included (mean age: 58 ± 15 years, 34% female). Rectus femoris cross-sectional area declined in the ICU (-4 mm2/day [95% confidence interval {CI}: -9 to 1]) and declined further in the ward (-9 mm2/day [95% CI: -14 to -3]) with a mean difference between ICU and ward of -5 mm2/day ([95% CI: -2, to 11]; p = 0.1396). There was a nonsignificant difference in ΔEI between in-ICU and the post-ICU ward of 1.2 ([95% CI: -0.1 to 2.6]; p = 0.0755), a statistically significant difference in ΔEISD between in-ICU and in the post-ICU ward of 1.0 ([95% CI, 0.5 to 1.5]; p = 0.0003), and no difference in rate of change in rectus femoris cross-sectional area between groups in intensive care (p = 0.411) or at hospital discharge (p = 0.1309).

CONCLUSIONS

Muscle wasting occurs in critical illness throughout the hospital admission. The average rate of loss in muscle cross-sectional area does not slow after ICU discharge, even with active rehabilitation.