Predictive Effect Of Inferior Vena Cava Collapse Index On Hypotension After Subarachnoid Block Anesthesia In Elderly Patients

BackgroundThe post-spinal anesthesia hypotension(PSAH)was a common complication with the blockade of preganglionic sympthetic fibres and reduction in both cardiac output and systemic vascular resistance.Elderly patients often have hypertension and decreased compensatory capacity of the cardiovascular system,which are more prone to hypotension after spinal anesthesia.Many attempts have been tried to prevent PSAH,such as intravenous volume preload.However,empirical volume loading carries the potential of volume overload,particularly in patients with cardiac disease.Ultrasound measurement of inferior vena cava diameter(IVC)and inferior vena cava collapse index(IVCCI)have been widely used to evaluate volume status and volume responsiveness,and whether they can predict hypotension after spinal anesthesia(PSAH)in elderly patients needs to be studied.MethodsThe study selected elderly patients undergoing elective surgery with spinal anesthesia.Before spinal anesthesia,The IVC diameter,IVC collapse index and their changes in calm breathing and standard breathing condition were measured in the supine and Passive Leg Raising position.After successful puncture,2ml of cerebrospinal fluid was fully mixed with 1%ropivacaine(2ml)and administered to subarachnoid space at 1ml every 5 seconds(4ml).observe the changes of noninvasive blood pressure within 30min after subarachnoid administration.the primary outcome were the maximum and minimum value of the inferior vena cava(IVCmax,IVCmin),inferior vena cava collapse index(IVCCI),and the lowest blood pressure within 30min after subarachnoid block anesthesia.The secondary outcome was the change in IVCCI between different respiratory states before and after passive leg lift(△ IVCCI).Results:A total of 71 elderly patients were included in this study,including 19 patients in the hypotensive group(5 males and 14 females)and 52 non-hypotensive groups(33 males and 19 females).Patients with an underlying history of hypertension are more likely to develop hypotension.The IVCCI was significantly higher in the hypotensive group than in the non-hypotensive group,while the IVCmin was significantly lower than in the non-hypotensive group.Under the ROC(Receiver Operating Characteristic)curve of the effect of IVCCI on hypotension after anesthesia in elderly patients under the supine calm breathing state,the area under the ROC curve was 0.795(95%CI 0.68-0.91),and the sensitivity of prediction was 68.4%and the specificity was 82.7%when the optimal truncation value of the IVCCI was 42.5%.The area under the ROC curve in the standard breathing state in the supine position was 0.783(95%CI 0.65-0.92),and the sensitivity of hypotension after anesthesia was 69.2%and the specificity was 74.4%when the IVCCI was 43.6%.The area under the ROC curve during calm breathing after passive leg lift was 0.780(95%CI 0.66-0.90).When the IVCCI was taken as 36.5%,the sensitivity and specificity of hypotension after anesthesia were 57.9%and 85.7%.The area under the ROC curve at the time of passive leg lift standard breathing was 0.713(95%CI 0.56-0.87).When the IVCCI was taken as 38.5%,the sensitivity and specificity of hypotension after anesthesia were predicted to be 60%and the specificity was 76.1%.When the IVCCI in the standard breathing state after passive leg lift increased,the decrease in MAP after anesthesia increased,but this correlation was weak(r~2=0.062 and 0.095,respectively).When the absolute value of the △IVCCI during calm breathing before and after passive leg lift>19.5%,the incidence of hypotensive events afteranesthesia increased in elderly patients.Conclusion:The inferior vena cava collapse index measured before subarachnoid block anesthesia has a good predictive effect on hypotension after subarachnoid block anesthesia in elderly patients,and passive leg lift test and standard breathing have no significant effect on the inferior vena cava collapse index on the prediction of hypotension after subarachnoid block anesthesia in elderly patients.When the absolute difference in inferior vena cava collapse index is 19.5%when the inferior vena cava collapse index difference is>before and after passive leg lifting,the incidence of hypotensive events after anesthesia increases.