Clinical Value Of Inferior Vena Cava Collapsibility Index In Evaluating Fluid Balance For Septic Patients

Objective: To observe effect of two different status of fluid balance on clinical outcomes for septic patients after SSCB, and to evaluate clinical value of inferior vena cava collapsibility index to predict fluid balance in septic patients.Methods: A prospective observational study was conducted,in which 94 septic patients after SSCB were enrolled. Recorded the fluid intake and output routinely in the first 3 days after admission, and then calculated the status of fluid balance. We have divided into two groups according to onset of negative fluid balance in the first 3 days. Two groups of fliud balance were shown: 47 patients with positive fluid balance(fluid intake always more than output in the first 3 days),and 47 patients with negative fluid balance(fluid output at least 1 d more than intake in the first 3 days).Recorded the clinical criteria for the worst condition in 24 hours after admission,the APACHE Ⅱscore of septic patients was calculated. Recorded septic patients general data 、underlying diseases、laboratory index、hospital stay、incidence of severe sepsis and MODS、mortality to observe effect of two different status of fluid balance on clinical outcomes for septic patients. For septic patients,serial transthoracic echocardiography was performed measuring and calculating stoke volume(SV),cardiac output(CO),left ventricular ejection fraction(LVEF). Heart rate(HR) and mean arterial pressure(MAP) was recorded when transthoracic echocardiography was performing. And then the inferior vena cava diameters at the end of expiration(IVCe)and inspiration(IVCi) was measured at 8 am and 8 pm in the first 3 days also after 24 h of negative fluid balance onset,the inferior vena cava collapsibility index(IVC-CI) was calculated. The AUC(area under the curve)of ROC predicating onset of negative fluid balance by IVC-CI was drawed.Results: No significantly differences were found for patients’ gender,age,hospital stays,underlying disease,TP,ALB,CR(both P>0.05). In positive fluid balance group, fluid intake and output were(3565.40±1201.65)ml、(2370.43±813.87)ml,these were(2270.09±968.64)ml、(3094.26±1089.65)ml in negative fluid balance group respectively. Fluid intake was decreased and fluid output was increased in negative fluid balance group(P<0.05).The APACHE Ⅱscore was significantly higher in positive fluid balance group than in negative fluid balance group in 24 hours after admission(P<0.05). In positive fluid balance group,the incidence of severe sepsis and MODS were significantly higher than in negative fluid balance group(both P<0.05).Mortality were significantly different in the type of fluid balance:negative fluid balance< positive fluid balance(P<0.01). No significantly differences were found for patients’ HR,MAP, SV,CO,LVEF(both P>0.05).In positive fluid balance, the inferior vena cava diameters at the end of expiration(IVCe)and inspiration(IVCi)were(16.57±3.48)mm、(8.98±3.51)mm, these were(16.77±2.52)mm、(7.57±1.64)mm in negative fluid balance group respectively.There is no significantly difference about the IVCe and IVCi when compared two groups(both P>0.05). Moreover, compared with positive fluid balance group, the IVC-CI was significantly increased in negative fluid balance group(54.98±5.78% vs.47.60±10.98%, P<0.05). The AUC of ROC predicating onset of negative fluid balance by IVC-CI was 0.705.The cut off value of IVC-CI for discrimination of negative fluid balance was determined as 52.79% with sensitivity of 72.3% and specificity of 61.7%.Conclusion: These results suggest that the status of fluid balance is closely related to clinical outcomes for septic patients, and the onset of negative fluid balance in the first 3 days after sepsis bundle could predicate a good prognosis.There are consistency between negative fluid balance and APACHEⅡto predict outcomes. The IVC-CI could evaluate negative fluid balance for septic patients with higher sensitivity than specificity.