| Objective: Verify the ED50 and the 95% confidence interval(CI)of isobaric ropivacaine used in obstetrical spinal anesthesia through sequential method,and provide a theoretical basis for clinical work.Method: We selected 90 full-term pregnant women,who selects cesarean section,of ASA grade 1-2 and of 155-170 cm height,as the subjects of this study.All of the subjects have no long-term psychotropic drug taking history,nor neuropsychiatric disorder history,nor subarachnoid block contraindication,nor amide local anesthetic allergy.Twin pregnancy,pregnancy-induced hypertension syndrome,placenta previa and multiple abdominal surgery history were excluded.These subjects(i.e.the 90 pregnant women)were divided into three groups: Group A was injected rapidly(0.4ml/s),Group B was injected using normal speed(0.1ml/s),and Group C was injected slowly(0.05ml/s).The initial dosage of Group A was set as 8mg(0.4ml/s),and the interval between levels was 0.5mg.The dosage for the first subject was 8mg.If the anesthetic effect is good,degrade the dosage for next subject;if the anesthetic effect is not good enough,upgrade the dosage for next subject.The initial dosage of Group B was 10mg(0.1ml/s),and initial dosage of 12mg(0.05ml/s)was used for Group C.The degrade and upgrade method for Group B and Group C were as same as method for Group A.Result: There is no significant difference in the basic items(P>0.05),including heart rate(HR),mean arterial pressure(MAP),age,body mass,body height,blood loss,infusion quantity,urine output,the time from medicine given to surgery completed,etc.The Chi-square test of Modified Bromage Scale(MBS)between 15-minute-later and 1-hour-later after medicine injection indicated that there was statistical difference between groups,and the rank correlation analysis indicated that they showed positively correlated.The results mean that if the dosage of spinal anesthesia ropivacaine was decreased,the depth of motor block was also corresponding reduced.In other words,under the premise of achieving the same block level and satisfying obstetric operation requirements,the dosage of isobaric ropivacaine should be corresponding reduced along with the fasten of injection.Group A spinal anesthesia ropivacaine: ED50 was 6.64 mg and the 95% CI was 6.286-6.936(95%CI=6.286-6.936),ED95 was 7.101 mg and the 95% CI was 6.800-7.526(95%CI=6.800-7.526).Group B spinal anesthesia ropivacaine: ED50 was 8.920 mg and the 95% CI was 8.622-9.177(95%CI=8.622-9.177),ED95 was 9.540 mg and the 95% CI was 9,263-10.027(95%CI=9,263-10.027).Group C spinal anesthesia ropivacaine: ED50 was 10.512 mg and the 95% CI was 10.109-10.843(95%CI=10.109-10.843),ED95 was 11.242 mg and the 95% CI was 10.895-11.811(95%CI=10.895-11.811).Compared the ED50 and ED95 of three groups,there was statistically significant(P<0.05).Conclusion: Using isobaric ropivacaine jet injection spinal anesthesia has the advantages of small dosage,good anesthesia effect,operable and can be widely used.By using this method,the dosage of local anesthesia drug can be reduced obviously,thus to reduce the probability of toxic reactions and complications triggered by large amount of local anesthesia drugs as well as lower limb motor block.This method is beneficial for postoperative recovery,has higher feasibility and safety and worth promoting. |
PDF Full Text Request