The possible predictive value of muscle ultrasound in the diagnosis of ICUAW in long-term critically ill patients

Abstract

Purpose: Intensive Care Unit acquired weakness (ICUAW) occurs commonly. Muscular ultrasonography allows visualization and classification of muscle characteristics. The aims of this study were to evaluate peripheral and respiratory muscles, their changes during long-term ICU stays, and the possible diagnostic predictive value of ICUAW as compared to the Medical Research Council strength score (MRC-SS).

Materials: 50 mechanically ventilated patients were enrolled. Within 48 h after ICU admission (T1), patients underwent muscular ultrasound (rectus femoris cross sectional area (RFCSA), pennation angle, diaphragm, and parasternal intercostal). All the same measures were repeated at days 3 (T3) and 7 (T7). Muscle strength assessment was performed using the MRC-SS.

Results: No significant differences were found regarding age, sex, weight, height, or BMI values, in those who developed ICUAW according to MRC-SS. The RF pennation angle, however, significantly changed between T7-T1 in patients who developed ICUAW and was. Found to be the best predictor of ICUAW.

Conclusions: Quadriceps and respiratory muscles were altered within the first week of mechanical ventilation. The loss of pennation angle offers high diagnostic accuracy for ICUAW, allowing for an earlier diagnosis before patients became able to perform volitional tests.

Keywords: Diaphragm and parasternal intercostal muscles; ICU acquired weakness; Muscle cross sectional area; Muscle layer thickness; Pennation angle; Peripheral muscular ultrasound; Skeletal muscle.