Effect of inferior vena cava variability in the assessment of volumetric reactivity in patients with coronary artery bypass grafting

Abstract

Objective To investigate the significance of inferior vena cava variability (IVCV) in the evaluation of volumetric reactivity in patients with coronary artery bypass grafting (CABG). Methods Totally 22 mechanical ventilation patients with pulmonary artery catheter (PAC) after CABG were collected, and the passive leg raising (PLR) tests were carried out on them in the first hour of intensive monitoring in the ICU ward. Patients with elevated cardiac output ≥ 15% after PLR were included in the volume-reactive positive group, while patients with elevated cardiac output < 15% were included in the volume-reactive negative group. The hemodynamic parameters of heart rate, arterial blood pressure, central venous pressure, pulmonary artery wedge pressure, cardiac output, end-diastolic volume index (EDVI), stroke volume, and the echocardiographic indexes of the maximum diameter of the inferior vena cava (IVCmax), the minimum diameter of the inferior vena cava (IVCmin) and the IVCV expression were all recorded before and after PLR in both groups. The general data, hemodynamic parameters and echocardiographic indexes of the two groups were compared, and then the predictive value of IVCV to volumetric reactivity was evaluated by the receiver operating characteristic curve (ROC). Results The age [(64 ± 8) years vs. (69 ± 6) years], the sex ratio (10/6 vs. 3/3) , the acute physiology and chronic health evaluation (APACHE) Ⅱ scores [(11.6 ± 2.7) vs. (12.7 ± 2.4)], the extracorporeal circulation time [(52 ± 32) min vs. (68 ± 34) min], the mechanical ventilation time [(11 ± 5) h vs. (12 ± 6) h] and the ICU residence time [(1.8 ± 1.0) d vs. (1.7 ± 0.5) d] all showed no statistically significant difference between the two groups (all P > 0.05). The expressions of cardiac output [(4.5 ± 0.8) mL/m2 vs. (5.0 ± 0.8) mL/m2], the stroke volume [(56 ± 9) mL vs. (62 ± 11) mL] and the IVCmin [(1.61 ± 0.28) cm vs. (9 ± 3) cm] before PLR were all significantly lower in the volume-reactive positive group compared to the volume-reactive negative group (t = 2.586, 2.236, 4.217; P = 0.012, 0.021, < 0.001). Meanwhile, the expression of IVCV [(21 ± 7)% vs. (68 ± 34)%] was higher in the volume-reactive positive group (t = 9.242, P < 0. 001). ROC curve analysis showed that the area under the curve of IVCV was 0.941 (95%CI: 0.879~1.000, P < 0.001) and it had predictive value for volumetric reactivity of patients after CABG. Conclusion IVCV could be used as an effective indicator for volumetric reactivity prediction in patients after CABG. Key words: Inferior vena cava variability; Volumetric reactivity; Passive leg raising; Coronary artery bypass grafting