The Predictive Value Of Carotid Corrected Flow Time And Respirophasic Variation In Blood Flow Peak Velocity For Postinduction Hypotension In Elderly Patients With Hypertension

Objective:Postinduction hypotension is common in elderly patients with hypertension.Because of arteriosclerosis,reduced arterial vascular compliance and elasticity in patients with hypertension,which leads to a decrease in the ability to regulate blood pressure.The aim of this study was to measure the carotid corrected flow time(FTc)respirophasic variation in carotid artery and blood flow peak velocity(△Vpeak-CA)using ultrasound and to evaluate their predictive value for postinduction hypotension in elderly hypertensive patients.Methods:A total of 86 hypertension patients conforming to schedule for elective surgery under general anesthesia,aged 65～75 years,ASA grade Ⅱ～Ⅲ,body mass index(BMI)18～30kg/m2 were enrolled.Basal heart rate(HR),systolic blood pressure(SBP),diastolic blood pressure(DBP),and mean arterial pressure(MAP)were recorded before induction of anesthesia.The systolic time(ST),circulation time(CT),maximum carotid peak velocity(maxVpeak-CA)and minimum carotid peak velocity(minVpeak-CA)were measured using ultrasound,and the carotid artery FTc and △Vpeak-CA were calculated.Intravenous injection of sufentanil 0.4ug·kg-1,midazolam 0.04mg·kg-1,imidate 0.3mg·kg-1 and rocuronium 0.6mg·kg-1 were used for induction of general anesthesia.HR,SBP,DBP and MAP were recorded every minute after induction.The standard of hypotension is that the MAP decrease rate is greater than 20%of the base value.The receiver operating characteristic(ROC)curve was performed to determine the ability of carotid FTc and △Vpeak-CA to predict postinduction hypotension for elderly patients with hypertension.Results:73 elderly patients with hypertension were included.The area under the ROC curve of carotid FTc is 0.840(95%CI 0.735～0.915 P<0.001),the best cut-off value is 11.16 ms0.5,ultrasound evaluation of carotid FTc had a sensitivity of 78.4%,a specificity of 77.3%,Youden index is 0.557.Carotid FTc has a high predictive value for hypotension after induction of general anesthesia.The area under the ROC curve of △Vpeak-CA is 0.658(95%CI 0.538～0.765P=0.036),the best critical value is 4.94(%),ultrasound evaluation of △Vpeak-CA had a sensitivity of 86.3%,a specificity of 45.5%,Youden index is 0.317.△Vpeak-CA has low predictive value for hypotension after induction of general anesthesia.73 patients were divided into 2 groups:hypotension group(group H)and non-hypotension group(group N)according to whether the patients had postinduction hypotension.There were 51 patients in group H and 22 patients in group N.The carotid FTc of group H was lower than that of group N(P<0.05),and the △Vpeak-CA of group H was higher than that of group N(P<0.05).Conclusions:In our study,the postinduction hypotension predictive value of carotid artery FTc was higher than that of △Vpeak-CA in elderly patients with hypertension.When carotid FTc<11.16 ms0.5,the elderly patients with hypertension are prone to have the incidence of postinduction hypotension.