A Study Of The Use Of Two Different Solutions Of Bupivacaine In Spinal Anesthesia For Cesarean Section

Background:SA(spinal anesthesia) is increasingly widely used in the cesarean delivery for its bestefficiency and guaranteed effect.Combined with epidural catheter insertion,the success rateof anesthesia can be improved more.However,compared with epidural anesthesia,the patientsundergoing SA are more likely to develope hypotension,especially for the parturients.Thetext book even takes SA as a contradiction for the parturients of middle-late stage.Socurrently the a relatively low dose anesthetic solution is commonly used to confine the blockheight,in order to protect the maternal and neonatal circulatory and respiratory systems toavoid too much side effects of anesthesia.Apart from the dose of bupivacaine,the baricityalso matters.Hyperbaric bupivacaine is conventionally used as it makes a reliable andregulatable block height,but many research suggested that the isobaric bupivacaine can alsobe reliable,and interferes circulatory and respiratory systems less.So this study is aimed tocompare two untraditional solutions of bupivacaine used in SA for cesarean section and thusget reference for the clinical practice.Method:60term parturients of ASA1-2with singleton pregnancy scheduled to receive cesareansection under SA were randemly equally divided into control group(group A),low-dosegroup(group B) and isobaric group(group C),receiving0.50%hyperbaric bupivacaine1.8ml(9mg),0.5%hyperbaric bupivacaine1.2ml(6mg) or0.5%isobaric bupivacaine1.8ml(9mg) respectively.After lumber puncture,the following parameters were evaluated:BP,HR,SpO2,upper limit of the sensorial blockade,degree of motor blockade,time forregression of the sensorial blockade by two dermatomes,requirement of epidural lidocavineor intravenous anesthetics,fluid and ephedrine received,maternal side effects,and neonatalApgar score at1and5min after delivery.Results:There was no difference between three groups in demographic and clinicalfeatures,BP,HR and SpO2.The SBP,DBP and MAP had significant difference between threegroups at10min after intrathecal injection.It showed that BP in group A are lower than thatin B which are lower than in C.Incidence of hypotension was greater in the contralgroup,resulting in a higher dose of ephedrine.There was no difference on LMAXand modified Bromage scores early,while it showed a decreased potency of block compared to the contralgroup.The time reaching T8was also shorer in the contral group.While the time of TPEAKandTDOWNwere longer in the isobaric group.There were more intense viscus traction response ingroup B compared with group A and C.The postoperative complications of parturients andApgar scores of neoborns at1min and5min showed no difference.Conclusions：It showed helpful effect of sustaining hemodynamic stability by using lower dose orisobaric bupivacaine in spinal anesthesia for cesarean section,resulting in a significant lowerincidence of hypotetion.But it can be more likely to see viscus traction response using areduced dose of bupivacaine only.So on the whole,it showed better effect of using isobaricsolution.