| Objective:First,we will discuss the predictive value of ultrasound measurement of inferior vena cava diameter（d IVC）and inferior vena cava collapsibility index（IVC-CI）on elderly patients with postspinal anesthesia hypotension（PSAH）.Due to differences in the general conditions of patients with preoperative hypertension and those without hypertension,we will explore whether preoperative hypertension affects the predictive value of IVC-CI for PSAH.On the basis of the first part of the study,IVC-CI is used to assess the blood volume of elderly patients before spinal anesthesia and then guide the infusion,and explore the influence on incidence of hypotension,ephedrine hydrochloride injection,phenylephrine hydrochloride injection and atropine sulfate injection in elderly patients after spinal anesthesia.Methods:In the first part,201 elderly patients who were electively operated under spinal anesthesia,aged60～89 years,the American Society of Anesthesiologists grade I-III were included in.The patient was instructed to fast for 8 hours and abstain from drinking for 4 hours before the operation.After the patient entered the operating room,the vein was routinely opened,but no fluid was injected before anesthesia.Spinal anesthesia was selected as the method of anesthesia.The puncture gap was L2～L3 or L3～L4.After successful puncture,0.5%ropivacaine 2.4～3.0 ml was injected,and the upper boundary of the sensory block plane was controlled at T8～T10.According to whether the preoperative diagnosis of hypertension is clinically confirmed,it is divided into a group with hypertension（group H）and a group without hypertension（group N）.And then according to whether hypotension occurs within 30 minutes after spinal anesthesia（SA）,the H and N groups were further divided into hypotension subgroup（D group）and non-hypotension subgroup（F group）.The maximum value of d IVC（d IVCmax）and IVC-CI were measured by ultrasound before and after SA,respectively.The systolic blood pressure（SBP）,mean arterial pressure（MAP）,and heart rate（HR）were recorded before and within 30 minutes after SA.The receiver operating characteristic curve（ROC）was used to evaluate the predictive value of d IVCmax and IVC-CI for PSAH.In the second part,the IVC-CI threshold（the IVC-CI threshold of group N is 37.6%,and the IVC-CI threshold of group H is 34.9%）were based on the results of the first part of the experiment.This partl included 156 elderly patients undergoing elective surgery under spinal anesthesia,who with IVC-CI greater than or equal to the threshold and ASA grade I-II.The included patients were randomly divided into the experimental group（S group）and the control group（C group）.In group S,after 10 minutes of infusion of 250 ml of compound electrolyte solution,IVC-CI was measured again,and the infusion was repeated until IVC-CI was lower than the threshold,but the total amount of infusion did not exceed 8 ml/kg,and the infusion time did not exceed 30 minutes.The compound electrolyte solution was infused for 30minutes at an infusion rate of 10 ml·kg-1·h-1in group C.The two subgroups were anaesthetized after fluid infusion.The anesthesia method is the same as that in the first part.Record the SBP,MAP,HR before anesthesia and within 30 minutes after anesthesia,the number of patients given ephedrine hydrochloride,phenylephrine hydrochloride,and atropine sulfate injection.Compare patients 10 min,20 min,and 30 min fluid infusion volume before anesthesia in group C and fluid infusion volume in group S.Compare the incidence of hypotension after anesthesia in elderly patients in group S and group C.Results:In the first part,163 patients were finally included,49 cases（30.1%）developed PSAH.The incidence of age,BMI,waist circumference,SBP,MAP,HR baseline values,and PSAH in group H were significantly higher than those in group N（P<0.05）.After the H and N groups were divided into two subgroups,except the gender difference between the two subgroups in the H group（P<0.05）,and the difference between the D group and F group of the other general conditions was not statistically significant.The d IVCmax before and after SA in group D was significantly smaller than that in group F（P<0.05）,and the IVC-CI before and after SA in group D was significantly greater than that in group F（P<0.01）.The area under the ROC curve（AUC）of PSAH predicted by IVC-CI before and after SA was significantly greater than d IVCmax before and after SA（P<0.05）.In group H,d IVCmax after SA in group D was significantly reduced compared with d IVCmax before SA,and IVC-CI was significantly increased compared with IVC-CI before SA（P<0.01）.From the ROC curve drawn by the Medcac software,it can be concluded that the area under the ROC curve（AUC）of the N group before and after SA to predict PASH is not statistically different from that of the H group before and after IVC-CI to predict PASH（Group N:0.915,0.917,Group H:0.919,0.933）,the sensitivity of IVC-CI before and after SA in group N and H to predict PASH（group N:85%,100%,group H:89.7%,96.6%）,specificity（group N:92.5%,80.6%,group H:80.9%,83.0%）,cut-off value（group N:37.6%,40.7%,group H:34.9%,39.6%）.The second part finally included 131 elderly patients,68 in N group and 63 in H group.After the N group and H group were divided into S and C subgroups,there was no statistically significant difference in the general condition of patients（P>0.05）.In the N group,45 patients were included in the S group,20cases（44.44%）occurred PSAH,and the C group included 23 patients,and 11 cases（47.83%）occurred PSAH.The incidence of hypotension in group S was lower than that in group C and the number of patients in group S who used ephedrine hydrochloride and atropine sulfate was less than that in group C,and the difference was not statistically significant（P>0.05）,while the number of patients required phenylephrine hydrochloride in group S was significantly less than that of group C,and the difference was statistically significant（P<0.05）.In the H group,33 cases were included in the S group,16 cases（48.48%）occurred PSAH,and the C group included 30 cases,and 15 cases（50.00%）occurred PSAH.The incidence of hypotension in group S was lower than that in group C,and the number of patients in group S who had used ephedrine,phenylephrine and atropine was less than that in group C,and the difference was not statistically significant（P>0.05）.The fluid infusion volume of group S is 500.00（250.00,500.00）ml before anesthesia,the volume of 10 min infusion of group C is 110.00（95.83,123.33）ml,and the volume of 20min infusion is 220.00（191.67,246.67）ml,the amount of fluid infusion before anesthesia in group S was significantly more than the 10-min fluid infusion volume and the 20-min fluid volume in group C（P<0.05）.In group S,there was no significant increase in SBP after fluid replacement compared with SBP after entering the room,but MAP after fluid replacement was significantly higher than that after entering the room,and the difference was statistically significant（P<0.01）.The changes of SBP and MAP in group C were not obvious after fluid supplementation.The MAP after anesthesia in the S group was not significantly lower than that after entering the room,and the MAP after anesthesia in the C group was significantly lower than that after entering the room（P<0.01）.The SBP of patients in group S and C was significantly lower after anesthesia than after entering the room（P<0.01）.Conclusion:IVC-CI before and after spinal anesthesia has certain value in predicting hypotension after spinal anesthesia in elderly patients with and without hypertension before surgery.The IVC-CI threshold for patients without hypertension is 37.6%,and IVC-CI threshold for patients with hypertension.is 34.9%.IVC-CI before spinal anesthesia can assess the blood volume of elderly patients before spinal anesthesia and guide fluid therapy. |
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