Association of baseline diaphragm, rectus femoris and vastus intermedius muscle thickness with weaning from mechanical ventilation

Abstract

Background: To determine whether baseline diaphragm (T_di), rectus femoris (RF) and vastus intermedius (VI) muscle thickness (T_RF and T_{RF + VI}) are associated with weaning success.

Material and methods: Right T_di, T_RF and T_{RF + VI} were measured by ultrasonography within 36 h of intubation and diaphragmatic excursion (DE) was evaluated at the first spontaneous breathing trial in adult critically-ill patients. Reintubation or death within 7 days after extubation was defined as weaning failure. Weaning failure and success groups were compared in terms of ultrasonographic measurements and clinical features.

Results: Thirty-eight patients were assessed for weaning, 15 (39.4%) being in the weaning failure group. The median body mass index (BMI) was lower while the median clinical frailty scale (CFS), vasopressor use, duration of mechanical ventilation, intensive care and hospital mortality rate were higher in the weaning failure group, and the median T_{RF + VI} (14.0 [12.3-26.2] vs 23.6 [21.3-27.1] mm, p = 0.03) and median DE (19.4 [14.6-24.0] vs 25.9 [19.3-38.5] mm, p = 0.045) were lower. The median T_di was similar in two groups (1.9 [1.5-2.3] vs 2.0 [1.7-2.4] mm, p = 0.26). In ROC analysis, area under the curve for T_{RF + VI} was 0.71 (95% CI: 0.51-0.90; p = 0.035), with 21 mm cut-off having sensitivity of 82% and specificity of 57%. Binary logistic regression analysis revealed T_{RF + VI} < 21 mm as the only predictor of weaning failure with an odds ratio of 10.5 (95% CI: 1.1-97.8, p = 0.038) after adjusting for age, sex, BMI and CFS.

Conclusions: T_{RF + VI} lower than 21 mm, measured by ultrasonography within 36 h of intubation, was associated with weaning failure among critically-ill patients.

Keywords: Critical care; Intensive care; Liberation from mechanical ventilation; Quadriceps femoris; Respiratory failure; Ultrasound.