The Effect Of Inferior Vena Cava Variability On Assessment Of Volume Responsiveness In Patients After Cardiac Bypass Surgery

Objective The aim of this study was to investigate the significance of inferior vena cava variability(ICVC)in predicting volume responsiveness(VR)of patients after cardiac bypass surgery(CABG).Methods Twenty-two patients with mechanical ventilation who underwent Pulmonery artery catheter(PAC or Swan-Ganz catheterization)after cardiac bypass surgery were performed the passive leg raising(PLR)test at the first,third and fifth hour after intensive care.We collected the relevant hemodynamic parameters such as:heart rate(HR),arterial blood pressure(ABP),the central venous pressure(CVP),pulmonary artery wedge pressure(PAWP),right ventricular end diastolic volume index(EDVI),stroke volume(SV),cardiac output(CO),IVCmax,IVCmin and IVCV before and after PLR,the IVC%=(IVCmax-IVCmin)/IVCmax.The patients with increased CO>15%after PLR were divided to Volume Responsiveness(VR)-positive group,the patients with CO<15%were divided to VR-negative group.The differences between the VR-positive group and the VR-negative group were compared,and the sensitivity and specificity of IVCV in predicting VR were analyzed with the receiver operating curve.Results There was no significant difference of clinical characteristics between the VR-positive group and the VR-negative group.Before the PLR test,the CO in patients in positive group was lower than that in negative group(4.495±0.776L/min vs 4.993±0.778 L/min),and the IVCmin and IVCV in VR-positive group were significantly different with those in VR-negative group(1.607±0.285cm vs 1.908±0.291cm)and(20.719±6.926%vs 8.263±1.717%),the other parameters such as HR,ABP,CVP,PAWP,EDVI,IVCmax showed no significant difference between the two groups.The ROC analysis of CVP,PAWP,EDVI,and IVCV predicted volume responsiveness showed that IVCV had the greatest sensitivity(91.9%)and specificity(86.2%)under the curve of capacity responsiveness to determine the patient’s maximum(0.941),the predictive value of other preload parameters to volume responsiveness was significantly lower than IVCV.Conclusion Monitoring the IVCV by echocardiography can be an effective predictor for volume responsiveness in patients undergoing mechanical ventilation after cardiac bypass surgery.