| Ropivacaine is characterized by significant sensory and motor block separation, which is less toxic than bupivacaine to the heart and the central nervous system. Since its application for the first time used in spinal anesthesia in the early90s, the safety of ropivacaine has been confirmed. Recently, ropivacaine has been approved to use in spinal anesthesia in China. The degree of muscle relaxation of some parturients is not satisfied or muscle relaxation time is not sufficient to meet the requirements of surgery when using ropivacaine for spinal anesthesia clinically.Therefore, whether suitability of ropivaine for spinal anesthesia and how to better use the drugs will be the hotspot for further research.Sufentanil is fentanyl N-4-Substituted derivatived derivatives,and its role in chemical and physics was first reported in1976.Since the80’s,the United States and Euprpe and ohter countries have begun to clinical research of sufentanil, with the constant deepening of research,which also expanded the scope of application., sufentanil is a highly selective μ-opioid receptor agonist,whose high-fat-solublity contributes to the high affinity with the nervous tissue such as spinal cord.Intrathecal administration could have a direct effect on the opioid receptor through the spinal dorsal horn. Meanwhile due to the easy diffusion to the head end, sufentanil has sedative effects, with local anesthetics together, may enhance the analgesic effects by alleviating the maternal traction to relieve anxiety and improve the quality of anesthesia. In addition, studies have implicated that local anesthetics combined with some doses of sufentanil could not only reduce its boluses, but also results in more hemodynamic stablity.An increasing number of morbidly obese parturients complicating with pregnancy induced presented annually in China due to social and physiological reasons. As morbid obesity affects most of the vital organs, the anesthesiologists must be prepared to deal with several anesthetic risk. The morbidly obese parturients and the cesarean delivery have already been non-dependent high risk factors of parturient death. Hemodynamic is instablity and anatomic physiology is changed because of pregnance and morbid obesity. The optimum dose of ropivacaine for spinal anesthesia clinically using in obese and nonobese parturients is not reported and there is nobody comparing their results. Many countries have begun to research of sufentanil in obstetrical application,but the clinical observations of obese and nonobese parturients have not reported. The aim of this study was to determine the effective dose (ED50/ED95) of intrathecal ropivacaine for cesarean delivery in nonobese parturients and morbidly obese parturients, and to determine the effective dose (ED50/ED95) of intrathecal ropivacaine with sufentanil for cesarean delivery in nonobese parturients and morbidly obese parturients using a Logistic regression model.Part one: ED50and ED95of Intrathecal hyperbaric0.5%ropivacaine in ParturientsObjective:The aim of the study was to determine the effective dose(ED5o/ED95) of intrathecal hyperbaric0.5%ropivacaine for cesarean delivery in nonobese parturients and morbidly obese parturients and to analysis and compare their hemodynamic and side effects.Methods:Forty-two parturients (BMI＜35) and (BMI≥35)(ASA â… or â…¡) respectively undergoing elective cesarean delivery were randomly assigned to receive intrathecal hyperbaric0.5%ropivacaine in dose of6,7,8,9,10,11or12mg(n=6). Combined spinal-epidural anesthesia was performed at the L2～3or L3-4interspace using a loss-of-resistance-to-air technique, with the patient in the left lateral decubitus position. The spinal component was performed with a needle-through-needle technique using a26-gauge Gertie Marx needle. After aspiration of cerebrospinal fluid, the intrathecal dose was injected over5-10s. A multiple-orifice spring-wound epidural catheter was threaded5cm into the epidural space. The drug was injected into the epidural catheter as necessary. Success (induction) was defined as a bilateral T6sensory level to pinprick within10min of the intrathecal drug administration. A failure (induction) was recorded when a T6sensory level was not obtained within10min after intrathecal drug administration. If a failure (induction) was recorded, an epidural supplementation was administered to attain a T6level. A success (operation) was defined as a successful initial sensory level, with no additional epidural anesthetic required during surgery. A failure (operation) was recorded when, despite an adequate T6sensory level, supplemental epidural analgesia was required to complete surgery. The ED50and ED95values were determined using a Logistic regression model.Results:ED50and ED95(with95%confidence intervals) for success (operation) were10.0(9.1～10.5) g and13.4(11.5～15.3) mg, respectively, in nonobese population,and were10.8(9.6～12.0) mg and16.0(11.0～21.0) mg, respectively, in obese population. There was no difference between two groups. There were no differences with regard to secondary outcomes (hypotension, vasopressor use, nausea, and vomiting).Conclusion:Obese and nonobese parturients undergoing cesarean delivery do not appear to respond differently to effective doses of intrathecal0.5%ropivacaine. We suppose the dose of ropivacaine in obese parturients needn’t decrease.Part two:ED50and ED95of Intrathecal hyperbaric0.5%ropivacaine with Sufentanil in ParturientsObjective:The aim of the study was to determine the effective dose (ED50/ED95) of intrathecal hyperbaric0.5%ropivacaine with sufentanil for cesarean delivery in nonobese parturients and morbidly obese parturients and to analysis and compare their hemodynamic and side effects..Methods:Forty-two parturients (BMI＜35) and (BMI≥35)(ASA â… orâ…¡) respectively undergoing elective cesarean delivery were randomly assigned to receive a6,7,8,9,10,11or12mg intrathecal hyperbaric0.5%ropivacaine dose with5μg fentanyl Combined spinal-epidural anesthesia was performed at the L2-3or L3-4interspace using a loss-of-resistance-to-air technique, with the patient in the left lateral decubitus position. The spinal component was performed with a needle-through-needle technique using a26-gauge Gertie Marx needle. After aspiration of cerebrospinal fluid, the intrathecal dose was injected over5-10s. A multiple-orifice spring-wound epidural catheter was threaded5cm into the epidural space. The drug was injected into the epidural catheter as necessary. Success (induction) was defined as a bilateral T6sensory level to pinprick within10min of the intrathecal drug administration. A failure (induction) was recorded when a T6sensory level was not obtained within10min after intrathecal drug administration. If a failure (induction) was recorded, an epidural supplementation was administered to attain a T6level. A success (operation) was defined as a successful initial sensory level, with no additional epidural anesthetic required during surgery. A failure (operation) was recorded when, despite an adequate T6sensory level, supplemental epidural analgesia was required to complete surgery. The ED50and ED95values were determined using a Logistic regression model.Results:ED50and ED95(with95%confidence intervals) for success (operation) were9.2(8.3～10.1)å'Œ12.1(11.2～13.5) mg, respectively, in nonobese population, and were9.5(9.0～11.0)å'Œ12.5(10.6～14.7) mg, respectively, in obese population. There was no difference between two groups. There were no differences with regard to secondary outcomes (hypotension, vasopressor use, nausea, and vomiting).Conclusion:Intrathecal hyperbaric0.5%ropivacaine with sufentanil for cesarean delivery could enhance the analogical effect and prolong anesthesia duration. Obese and nonobese parturients undergoing cesarean delivery do not appear to respond differently to effective doses of intrathecal0.5%ropivacaine with sufentanil. We suppose the dose of ropivacaine in obese parturients needn’t decrease. |
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