Carotid Corrected Flow Time And Respirophasic Variation In Blood Flow Peak Velocity For Assessing Fluid Responsiveness And Creatinga Prediction Model

Objective:Routine fasting and bowel preparation before operation could cause volume loss and lead to volume deficiency,which increased the risk of hypotension after induction of general anesthesia,and perioperative hypotension was closely associated with adverse postoperative complications.Ultrasonic measurement of carotid artery corrected blood flow time and variation of carotid peak velocity were reliable methods to evaluate the fluid responsiveness.In this study,carotid artery corrected blood flow time and respirophasic variation in carotid artery blood flow peak velocity were applied to assess fluid responsiveness and establish a predictive model,so as to explore the value of this model in predicting fluid responsiveness.Methods:76 patients undergoing preoperative bowel preparation were recruited for selective surgery under general anesthesia.After entering the preparation room,all patients were routinely monitored for heart rate(HR),mean arterial pressure(MAP),pulse oxygen saturation(SpO2)and electrocardiogram(ECG),the venous passage was established,compound sodium chloride injection(10ml/kg)was infused intravenously in 25-30min.HR,MAP,stroke volume(SV),systolic flow time(ST),cardiac cycle(CT),maximum carotid peak velocity(ΔVpeak-max)and minimum carotid peak velocity(△Vpeak-min)were recorded before and after fluid challenge,and then carotid corrected flow time(FTc)and variation of carotid peak velocity(△Vpeak-CA)were calculated.Fluid responsiveness was defined as 10%or more increase in SV after the fluid challenge.Receiver operating characteristic(ROC)curves of carotid FTc and △Vpeak-CA was drawn,and the diagnostic threshold was determined.The prediction model W combined FTcand ΔVpeak-CA was createdby multivariate logistic regression analysis,the predictive value of prediction model W for fluid responsiveness was analyzed and compared with that of carotid FTc and △Vpeak-CA.Results:Data from 61 patients were finally analyzed in the study,61 patients were divided into group R(Responder group,group R)and group N(Non-responder group,group N)according to an increase of SV(△SV)greater than 10%from baseline after the fluid challenge,there were 40 patients in group R and 21 patients in group N.The SV of group R and group N was increased after the volume challenge,but the △SV in group N was less than 10%.After the volume challenge,carotid artery FTc was increased andΔVpeak-CA was decreased in two groups.Area(95%confidence interval)under the ROC curves of FTc was 0.774(0.652-0.897),when the cut-off value of FTc was 11.10ms0.5,the sensitivity was 80%and specificity was71.4%;Area(95%confidence interval)under the ROC curves of ΔVpeak-CA was 0.768,when the cut-off value of ΔVpeak-CA was 8.95%,the sensitivity was 77.5%and specificity was 61.9%.A prediction model W was established by combining carotid FTc and ΔVpeak-CA to predict fluid responsiveness,the area(95%confidence interval)under the ROC curves of this prediction model was 0.857,the sensitivity was 82.5%and specificity was 81%.Conclusions:Carotid FTc or △Vpeak-CA could be used to predict fluid responsiveness when the cut-off value of FTc was 11.1ms0.5 or ΔVpeak-CA was 8.95%in patients undergoing selective surgery under general anesthesia.The predictive value of prediction model W was higher than that of carotid FTc or ΔVpeak-CA only.