Predictability Of Subclavian Vein Collapsibility Index For Hypotension After Spinal Anesthesia In Parturients Undergoing Cesarean Section

Background:Spinal anesthesia is one of the common anesthetic methods for cesarean section.Due to the decrease of systemic vascular resistance caused by autonomic nerve block after spinal anesthesia and the compression of inferior vena cava by the enlarged uterus,hypotension after spinal anesthesia is very common that can produce varying degrees of advers e reactions to mothers and infants.With the development of ultrasound visualization,the application of ultrasound in predicting hypotension after spinal anesthesia has become a research hotspot.ultrasonic measurement of subclavian vein collapse index is simple and easy,and has been proved to be a reliable index to evaluate the liquid response of critically ill patients with sedation and mechanical ventilation,but its application in predicting hypotension after spinal anesthesia remains to be further st udied.Objective:To investigate the predictability of subclavian vein collapsibility index for hypotension after spinal anesthesia in parturients undergoing cesarean section.Methods:78 healthy full-term parturients with singleton undergoing cesarean section under spinal anesthesia were selected.The basic non-invasive arterial blood pressure and heart rate were recorded before anesthesia.The internal diameter of subclavian vein（d SCV）was measured by ultrasound during natural expiration,calm inspirati on and deep inspiration,and the subclavian vein collapsibility index（SCV-CI）during calm inspiration and deep inspiration were calculated respectively.Blood pressure and heart rate were recorded every two minutes during the 15-min period after spinal anesthesia.According to whether hypotension occurred after spinal anesthesia,the parturients were divided into two groups:hypotension group（group H）and non-hypotension group（group N）.Results:A total of 69 parturients were included in this s tudy.According to whether hypotension occurred after spinal anesthesia,69 parturients were divided into two groups:hypotension group（group H,n=37）and non-hypotension group（group N,n=32）.The lowest systolic blood pressure（SBP）,percentage of decre ase in systolic blood pressure,SCV _{calm inspiration}-CI and SCV _{deep inspiration}-CI in hypotension group were significantly higher than those in non-hypotension group（P<0.05）.The percentage of decrease in systolic blood pressure was positively correl ated with the SCV _{calm i n s p i r a t io n}-CI and SCV _{deep inspiration}-CI.The areas under the receiver-operating characteristic curves（ROC）for SCV _{c a l m i n s p i r a t i o n}-CI and SCV _{d e e p in s p i r a t io n}-CI were 0.688[95%confidence interval（CI）,0.564to 0.812]and0.807（95%CI,0.698 to 0.915）;The optimal cut-off values for predicting hypotension were 21.3%and 34.7%;The sensitivity were 62.2%and83.3%;The specificity were 68.7%and 78.1%.Multivariate Logistic regression analysis of predicting hypotension after spinal anesthesia,SCV c a l m i n s p i r a t io n-CI and SCV deep inspiration-CI before anesthesia are independent predictors of hypotension after spinal anesthesia in parturients undergoing cesarean section.Conclusion:The subclavian vein collapsibility index during calm inspiration and deep inspiration before spinal anesthesia are important predictors of hypotension after cesarean section.Further research is needed to confirm our findings,then it can be recommended for clinical use.