ABSTRACT
Objective:To identify the feasibility of inferior vena cava variability (ΔDIVC) combined with rectus femoris atrophy fraction in predicting the outcome of weaning from invasive mechanical ventilation (IMV).Methods:From January to December 2021, the patients with the need for IMV admitted to the Affiliated Yixing Hospital of Jiangsu University were recruited into prospective case-control study. The patients who met the withdrawal criteria were treated with a 2-h spontaneous breathing trial (SBT) and then extubated immediately. Patients with stable spontaneous breathing after extubation for more than 48 h were classified as successful weaning group, and on the contrary, the other patients were classified as failed weaning group. The clinical data and withdrawal indexes of the two groups were evaluated. The correlation between ΔD IVC and rectus femoris atrophy fraction was assessed. The influencing factors of weaning outcome were observed. The diagnostic value of ΔD IVC, rectus femoris atrophy fraction and the combination of two indexes in predicting weaning success were calculated by a plotting receiver operating characteristic (ROC) curve. Results:Sixty IMV patients were included in this study, including 38 cases of successful weaning and 22 cases of failed weaning. The two groups were comparable with regard to clinical data (all P>0.05). The rectus femoris cross-sectional area in the two groups diminished gradually with the length of ICU stay ( F=3.266, 3.625, both P<0.05). The rectus femoris cross-sectional area at the first SBT was significantly lower than that on the first day of admission in both groups [the successful weaning group: (2.54±0.88) cm 2vs. (3.08±0.98) cm 2; the failed weaning group: (2.22±0.87) cm 2vs. (3.02±1.10) cm 2, both P<0.05], but there was no significant difference between the two groups (all P>0.05). Patients in the successful weaning group had higher ΔD IVC and higher rectus femoris atrophy fraction than those in the weaning failure group [ΔD IVC: (25.02±4.65)% vs. (20.30±3.16)%; rectus femoris atrophy fraction: (81.89±5.09)% vs. (72.68±8.98)%, both P<0.05]. There was a positive correlation between ΔD IVC and rectus femoris atrophy fraction ( r=0.346, P=0.007). Both ΔD IVC and rectus femoris atrophy fraction played an important role in affecting weaning success (all P<0.05). The area under the curve (AUC) of ΔD IVC combined with rectus femoris atrophy fraction for predicting the weaning success was 0.880, which was significantly higher than that of ΔD IVC (AUC=0.791) or rectus femoris atrophy fraction (AUC=0.826). Conclusions:The predictive value of ΔD IVC combined with rectus femoris atrophy fraction for successful weaning of patients undergoing IMV is relatively accurate, which can be used to guide weaning.