Bupivacaine disposition in mother, fetus, and neonate after spinal anesthesia for cesarean section

Uptake of bupivacaine from the subarachnoid space and its placental transfer were measured in six patients undergoing elective cesarean section. Maternal plasma levels (59 +/- 32 ng/ml) were only about 5% of those found in a comparable previous study of epidural anesthesia. Mean plasma umbilical venous bupivacaine levels (20.2 +/- 21 ng/ml) were 7% of those found after epidural anesthesia. Mean umbilical venous/maternal venous bupivacaine ratios were 0.34 +/- 0.12 and mean umbilical arterial/umbilical venous ratios were 0.81 +/- 0.30. No bupivacaine was detectable in neonatal plasma 24 hr after delivery. Neonatal urine had measurable levels of both bupivacaine and its inactive metabolite, 2,6-pipecolylxylidine (PPX), for at least 36 hr after delivery. The results demonstrate that bupivacaine crosses the placenta and reaches the fetus, but in very low amounts. This transplacental passage occurs despite injection of only small doses of a very highly protein bound drug into the subarachnoid space.     

Effect of ranitidine on bupivacaine disposition

This study was undertaken to determine the effect, if any, of ranitidine on bupivacaine disposition in 28 women undergoing cesarean section. Before epidural anesthesia, ranitidine (50 mg IM) or sodium citrate (30 mL orally) was administered to groups of 14 parturients each. Ranitidine was administered 2 h before epidural anesthesia and sodium citrate was administered 10 min before the epidural. Maternal plasma samples were collected after epidural anesthesia with bupivacaine. A total of 15 maternal plasma samples were taken from the time of administration of epidural anesthesia up to 180 min. Postpartum plasma and urine samples were also collected from both mothers and neonates. Plasma samples were collected up to 48 h postpartum at intervals of 12, 24, and 48 h. Urine samples were collected at six 6-h intervals up to 36 h postpartum. A two-way analysis of variance with repeated measures demonstrated that there was no significant difference in bupivacaine levels between the maternal plasma curves of the ranitidine and the control groups. At the time of delivery, plasma levels of bupivacaine and its N-dealkylated metabolite PPX (2,6-pipecolylxylidine) were no different in the mothers or neonates of either group. There was no significant difference in plasma protein binding of bupivacaine in the presence of ranitidine. The excretion rates of bupivacaine and PPX were not measurably influenced by ranitidine. The amount of bupivacaine excreted, the amount of metabolite excreted, and the percentage of drug excreted as metabolite in maternal urine were not significantly different. These data indicate that there is no measurable effect of ranitidine on the disposition of bupivacaine in parturients.     

Excretion of lidocaine and bupivacaine in breast milk following epidural anesthesia for cesarean delivery

BACKGROUND: There is a lack of information and knowledge about the practical importance of even low concentrations of the excretion of local anesthetics into breast milk, particularly concerning bupivacaine. The present work aims to confirm, under practical clinical conditions of admission of parturients, the passage of local anesthetics (lidocaine and bupivacaine) into breast milk after an epidural anesthesia. METHODS: Twenty-seven pregnant women admitted for cesarean delivery received epidural anesthesia with 0.5% bupivacaine and 2% lidocaine. Blood and milk samples were simultaneously collected at 2, 6 and 12 h after the beginning of the epidural infusion. Lidocaine, bupivacaine and its main metabolite, pipecolylxylidide (PPX), were determined in serum and milk by a gas-liquid chromatographic technique. APGAR scores were systematically performed at delivery and a clinical examination was done 24 h after delivery. RESULTS: Our data indicate that lidocaine and bupivacaine as well as PPX are excreted into breast milk. The milk/serum ratio based upon area under the curve values were 1.07 +/- 0.82, 0.34 +/- 0.24 and 1.37 +/- 0.61 mean +/- SD for lidocaine, bupivacaine and PPX, respectively. Most of the newborns had a maximal APGAR score. Our study does not reveal any adverse reactions related to the excretion of local anesthetics into breast milk. CONCLUSION: This study documents the magnitude of excreted lidocaine, bupivacaine and PPX in breast milk, and indicates that the use of both lidocaine and bupivacaine for epidural anaesthesia is safe with regard to breast-feeding.     

Combined spinal and epidural anesthesia for cesarean section: a retrospective study with 0.5% hyperbaric bupivacaine

BACKGROUND: We investigated retrospectively the relationship between the intrathecal dose of 0.5% hyperbaric bupivacaine and the use of 2% mepivacaine through an epidural catheter. METHODS: Forty-nine patients undergoing cesarean section with combined spinal and epidural anesthesia (CSEA) were analyzed. They were divided into two groups; with (CSEA group) and without additional epidural injection group (spinal group). RESULTS: In the CSEA group (24 patients received 1.2 +/- 0.4 ml of 0.5% hyperbaric bupivacaine), 5-10 ml of 2% mepivacaine were required to achieve the adequate surgical anesthesia. In the spinal group (25 patients received 1.6 +/- 0.3 ml of 0.5% hyperbaric bupivacaine), cesarean section was performed without additional mepivacaine before delivery. The analgesic level and the amount of fluid infusion were similar in the two groups. However, 20% of patients in the spinal group showed hypotension (systolic blood pressure below 80 mmHg), although no patients in the CSEA group developed hypotension. The amount of ephedrine used before delivery was significantly larger in the spinal group (8.9 +/- 7.7 mg) than in the CSEA group (3.9 +/- 4.3 mg). CONCLUSIONS: Spinal anesthesia induced by 1.2 ml of 0.5% hyperbaric bupivacaine with sequential epidural block induced by 5-10 ml of 2% mepivacaine caused no hypotension during cesarean section.     

Transient maternal hypotension following epidural anesthesia

Transient maternal hypotension following regional anesthesia can lead to significantly lower umbilical cord pH values. Although this acidosis has not been found to be clinically significant, acidosis may increase the placental transfer of local anesthetic agents as a result of "ion trapping." The purpose of this study was to examine the pharmacologic and clinical consequences of transient maternal hypotension following epidural anesthesia with 0.5% bupivacaine before cesarean section. Patients were divided into two groups based on the development of maternal hypotension, defined as a systolic blood pressure less than 100 torr or a decrease of 30% or more from the preanesthetic level. Thirteen patients (33%) developed hypotension that was corrected within 2.1 +/- 1.8 min. The pH of umbilical cord venous and arterial blood and the concentration of bupivacaine were significantly lower (P less than 0.05) in neonates of mothers in the hypotensive group than in neonates of mothers that did not develop hypotension. The results show, however, that transient maternal hypotension following epidural anesthesia does not lead to a greater placental transfer of bupivacaine due to "ion trapping" even though neonatal cord blood pH decreases.     

Lidocaine disposition in mother, fetus, and neonate after spinal anesthesia

Although it is generally believed that concentrations of local anesthetic in maternal plasma do not reach levels that affect the fetus after spinal anesthesia, there are few studies that have measured drug levels in either maternal or neonatal plasma after spinal anesthesia. The purpose of this study was to document the disposition of lidocaine in mother, fetus, and neonate after spinal anesthesia using gas chromatographic/mass spectrometric measurement of lidocaine and two metabolites of lidocaine. Plasma concentration time curves, fetal/maternal ratios, cord artery/cord vein ratios, and neonatal urine levels were determined in ten patients. The results document that lidocaine is present in maternal and neonatal plasma. Mean (+/- SD) maternal plasma levels (0.65 +/- 0.52 micrograms/ml) were significantly lower than those previously reported after epidural anesthesia (2.09 +/- 1.31 micrograms/ml). Fetal/maternal plasma concentration ratios averaged 0.37 +/- 0.2 and mean cord arterial/cord venous ratios 0.5 +/- 6.7. Lidocaine and its metabolites were present in neonatal urine for longer than 36 hr. This study demonstrates that spinal anesthesia with lidocaine results in neonatal exposure to lidocaine.     

Comparison of general and epidural anesthesia in elective cesarean section for placenta previa totalis: maternal hemodynamics, blood loss and neonatal outcome

There are few consistent guidelines in choosing anesthesia for cesarean section for a parturient with placenta previa. This prospective randomized trial was organized to compare the maternal hemodynamics, blood loss and neonatal outcome of general versus epidural anesthesia for cesarean section with the diagnosis of grade 4 placenta previa. After giving informed consent, 12 patients received general anesthesia and 13 received epidural. Intraoperative blood pressures demonstrated a more stable course in the epidural group than in the general group. Blood loss did not differ significantly between the groups (1622 +/- 775 mL vs. 1418 +/- 996 mL). General anesthesia resulted in lower immediate postoperative hematocrit level (28.1 +/- 3.5% vs. 32.5 +/- 5.0%, P < 0.05). The patients in the general group received a significantly larger transfusion than the epidural group (1.08 +/- 1.6 vs. 0.38 +/- 0.9 units, P < 0.05). The Apgar scores at 1 and 5 min were similar in the two groups (8 [4-9] vs. 8 [7-9] and 10 [6-10] vs. 9 [9-10], respectively). We concluded that epidural anesthesia is superior to general anesthesia in elective cesarean section for grade 4 placenta previa with regard to maternal hemodynamics and blood loss. There was no difference in neonatal outcome.     

Spinal versus epidural anesthesia for cesarean section in severely preeclamptic patients: a retrospective survey.

BACKGROUND: Selection of spinal anesthesia for severely preeclamptic patients requiring cesarean section is controversial. Significant maternal hypotension is believed to be more likely with spinal compared with epidural anesthesia. The purpose of this study was to assess, in a large retrospective clinical series, the blood pressure effects of spinal and epidural anesthesia in severely preeclamptic patients requiring cesarean section. METHODS: The computerized medical records database was reviewed for all preeclamptic patients having cesarean section between January 1, 1989 and December 31, 1996. All nonlaboring severely preeclamptic patients receiving either spinal or epidural anesthesia for cesarean section were included for analysis. The lowest recorded blood pressures were compared for the 20-min period before induction of regional anesthesia, the period from induction of regional anesthesia to delivery, and the period from delivery to the end of operation. RESULTS: Study groups included 103 women receiving spinal anesthesia and 35 receiving epidural anesthesia. Changes in the lowest mean blood pressure were similar after epidural or spinal anesthesia. Intraoperative ephedrine use was similar for both groups. Intraoperative crystalloid administration was statistically greater for patients receiving spinal versus epidural anesthesia (1780 +/- 838 vs. 1359 +/- 674 ml, respectively). Neonatal Apgar scores and incidence of maternal intensive care unit admission or postoperative pulmonary edema were also similar. CONCLUSION: Although we cannot exclude the possibility that the spinal and epidural anesthesia groups were dissimilar, the magnitudes of maternal blood pressure declines were similar after spinal or epidural anesthesia in this series of severely preeclamptic patients receiving cesarean section. Maternal and fetal outcomes also were similar.     

The pharmacokinetics and maternal and neonatal effects of epidural lidocaine in preeclampsia

The pharmacokinetics and maternal and neonatal effects of epidural lidocaine were compared in ten preeclamptic and five normotensive women undergoing cesarean section at 36-40 weeks of gestation. Lumbar epidural anesthesia was achieved using 15-20 ml of 2% lidocaine without epinephrine. Serial venous samples for lidocaine levels were drawn from all the mothers during the procedure and up to 6 hr after the initial injection. Umbilical venous and arterial samples were drawn at delivery for measurement of neonatal acid-base status and lidocaine levels. There were no significant differences between normotensive and preeclamptic patients in the total dose of lidocaine, peak maternal plasma concentration, volume of distribution, maternal elimination half-life and umbilical vein/maternal vein ratios. The calculated area under the concentration time curve in preeclamptic patients (18.5 +/- 4.7 micrograms X hr X ml-1) was significantly greater than in normotensive mothers (14.1 +/- 1.3 micrograms X hr X ml-1) (P less than 0.02). Total maternal body clearance in preeclamptic patients (24.5 +/- 7.1 L/hr) was significantly lower than in normotensives (31.1 +/- 4.4 L/hr) (P less than 0.05). Neonatal outcome as evaluated by Apgar scores, umbilical arterial and venous blood gas tensions, umbilical vein/maternal vein ratios, and early neonatal neurobehavior scores at 4 hr and 24 hr after birth were similar in the two groups. The results indicate that the total maternal body clearance of lidocaine is prolonged in preeclampsia, and repeated administration of lidocaine can result in higher blood levels than in normotensive parturients.     

Cardiac function and sympathoadrenal activity in the newborn after cesarean section under spinal and epidural anesthesia

Left ventricular systolic time intervals, bupivacaine concentrations, adrenaline and noradrenaline levels were determined in 19 neonates delivered by elective cesarean section. Ten of the cesarean sections were performed under spinal and nine under epidural anesthesia. Plain bupivacaine 0.5% was used for the epidural anesthesia and bupivacaine 0.5% in glucose 8% for the spinals. The noradrenaline and adrenaline levels were higher in the neonates whose mothers received epidural anesthesia. The differences in catecholamine and bupivacaine concentrations were not associated with differences in left ventricular dynamics, or the timing of postnatal circulatory changes. The significant exposure of the neonate to bupivacaine, at maternal epidural anesthesia, seems to have no negative effect on early neonatal circulation in the healthy term infant.     

Spinal versus Epidural Anesthesia for Cesarean Section in Severely Preeclamptic Patients: A Retrospective Survey

Background: Selection of spinal anesthesia for severely preeclamptic patients requiring cesarean section is controversial. Significant maternal hypotension is believed to be more likely with spinal compared with epidural anesthesia. The purpose of this study was to assess, in a large retrospective clinical series, the blood pressure effects of spinal and epidural anesthesia in severely preeclamptic patients requiring cesarean section.

Methods: The computerized medical records database was reviewed for all preeclamptic patients having cesarean section between January 1, 1989 and December 31, 1996. All nonlaboring severely preeclamptic patients receiving either spinal or epidural anesthesia for cesarean section were included for analysis. The lowest recorded blood pressures were compared for the 20-min period before induction of regional anesthesia, the period from induction of regional anesthesia to delivery, and the period from delivery to the end of operation.

Results: Study groups included 103 women receiving spinal anesthesia and 35 receiving epidural anesthesia. Changes in the lowest mean blood pressure were similar after epidural or spinal anesthesia. Intraoperative ephedrine use was similar for both groups. Intraoperative crystalloid administration was statistically greater for patients receiving spinal versus epidural anesthesia (1780 +/- 838 vs. 1359 +/- 674 ml, respectively). Neonatal Apgar scores and incidence of maternal intensive care unit admission or postoperative pulmonary edema were also similar.     

硬膜外阻滞剖宫产术中静脉输入乳酸钠林格氏液对母婴的影响

用１７０例硬膜外阻滞下行择期剖宫产术的健康产妇，观察静脉输入乳酸钠林格氏液（林乳液）对产妇动脉血和新生儿脐带血的血气、血糖、红细胞比积、血浆电解质、血浆渗透压及阴离子间隙等血液生化指标的影响。所有产妇随机分为输液组（１３８例）及对照组（３２例），输液组于麻醉诱导至胎儿娩出期间经母体静脉输入林乳液１０００ｍｌ。结果表明，在胎儿娩出时输液组产妇及新生儿上述血液生化指标与对照组相比均无显著差异，两组产妇此时的血液生化指标与麻醉前相比也无显著变化。提示：林乳液可应用于健康产妇硬膜外阻滞剖宫产术，对母婴的生化代谢状态无不良影响。     

The maternal hemodynamic effects of bupivacaine-epinephrine mixture used for obstetrical anesthesia

The maternal hemodynamic effects of bupivacaine (0.5%)-epinephrine (5 micrograms/ml) mixture used for lumbar epidural anesthesia were studied with an impedance cardiograph and an automated blood pressure device in term gravidas undergoing elective cesarean section. Following i.v. hydration with 2000 ml Ringer's lactate solution, 16 patients received bupivacaine-epinephrine mixture and 16 patients plain bupivacaine in 5-ml increments to a T4 level. Measurements were made before anesthesia, at T10 and at T4 sensory levels. Results were analyzed using analysis of variance (ANOVA) and the least significant difference method at P less than 0.05. In the epinephrine group, at T10 level, the diastolic (D) and mean (M) pressures decreased significantly 11 +/- 3, and 10 +/- 1% (mean +/- s.e. mean) respectively with no significant change in the S pressure. No significant changes were seen in the plain group. At T4, the S, D and M pressures decreased significantly 8 +/- 2, 18 +/- 4 and 16 +/- 2% in the epinephrine group. In the plain group the decrease in each one of these pressures was less than 5% and was not significant. In the epinephrine group, S, D and M pressures decreased significantly more than they did in the plain group at T10 and T4. Systemic vascular resistance decreased significantly from control values by 19 +/- 6% at T4 in the epinephrine group with no significant changes in the plain group.(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of bupivacaine as an adjuvant to epidural morphine for analgesia after cesarean section

The effect of the addition of bupivacaine to epidural morphine (EM) on postoperative analgesia was evaluated in 150 patients after cesarean section performed under epidural anesthesia with carbonated lidocaine. Fifty patients received 3 mg EM without bupivacaine, 50 received 3 mg EM with 0.125% bupivacaine, 25 received 5 mg EM without bupivacaine, and 25 patients received 5 mg EM with 0.125% bupivacaine. Patients were assessed for quality and duration of postoperative analgesia, as well as the incidence and severity of side effects. The addition of bupivacaine did not affect the quality or duration of analgesia afforded by EM and did not influence the incidence or severity of side effects. Furthermore, there was no statistically significant difference in the analgesia obtained by patients receiving 3- and 5-mg doses of EM with or without bupivacaine.     

Feto-maternal distribution of epidural drugs used in obstetric analgesia and anesthesia

Due to the potential fetal exposure of drugs used in regional epidural block for labor analgesia and cesarean section anesthesia it is important to understand the factors governing the transplacental transfer of these drugs. Published information on the feto-maternal distribution of the commonly used local anesthetics (lidocaine and bupivacaine) as well as new drugs such as ropivacaine and the alpha-2 agonists (clonidine and dex-medetomidine), however, is sparse. A dual-perfused human placental cotyledon model was established to evaluate the transplacental transfer of two local anesthetics (lidocaine and bupivacaine) and alpha-2 agonists (clonidine and dexmedetomidine) in vitro. The feto-maternal distribution of local anesthetics was also studied in vivo after epidural administration for elective cesarean section. Healthy term parturients scheduled for elective cesarean section were randomly allocated in a double-blinded manner to receive either ropivacaine or bupivacaine. Similarly, another group of parturients was randomized to receive either bupivacaine or lidocaine-epinephrine through a lumbar epidural catheter. During in vitro placental perfusion, the highly lipophilic bupivacaine and dexmedetomidine were rapidly cleared from the maternal circulation but appeared in low concentrations in the fetal circulation. Conversely, lidocaine and clonidine were cleared less rapidly from the maternal circulation and appeared in higher concentrations in the fetal circulation than did bupivacaine or dexmedetomidine. Substantial amounts of dexmedetomidine were found in the perfused placental cotyledon. In a clinical study after the epidural administration of equal doses of either ropivacaine or bupivacaine, the maternal venous, the umbilical venous and the arterial free drug concentrations of ropivacaine at delivery were approximately twice as high as those for the more lipophilic bupivacaine. The maternal plasma clearance of free bupivacaine was significantly higher than that of ropivacaine. After the epidural administration of lidocaine-epinephrine or bupivacaine, the fetal/maternal concentration ratios, the total amount of drug retained in the placenta as well as the areas under the concentration versus time curves per unit of dose were similar with a higher incidence of maternal hypotension in the lidocaine-epinephrine group for cesarean section. The in vitro human placental perfusion method proved to be a useful method for the study of the transplacental distribution of drugs used in parturients. Both in vivo and in vitro, the rapid clearance of highly lipophilic drugs from the maternal circulation, thereby lowering their maternal concentrations, restricted their transplacental transfer to the fetal circulation. This can likely be explained by their higher maternal volume of distribution, and was associated with their uptake into the placental tissue in vitro. Maternal hemodynamics seem to be an important determinant of transplacental drug transfer during epidural anesthesia, probably through their effect on the maternal distribution of drugs. This study indicates that bupivacaine leads to a lower fetal drug exposure compared to lidocaine or ropivacaine. Similarly, according to the perfusion study, dexmedetomidine leads to a lower fetal drug exposure compared to clonidine.     

Epidural blood flow and regression of sensory analgesia during continuous postoperative epidural infusion of bupivacaine

Epidural blood flow was measured in seven patients undergoing elective abdominal surgery during combined lumbar epidural and general anesthesia. After an initial dose of 20 ml plain bupivacaine 0.5%, a continuous epidural infusion of bupivacaine 0.5% (8 ml/hr) was given for 16 hours for postoperative pain relief. The epidural blood flow was measured by a local 133Xe clearance technique in which 15-35 MBq 133Xe diluted in 1 ml saline was injected through the epidural catheter on the day before surgery (no bupivacaine), 30 minutes after the initial dose of bupivacaine on the morning before surgery, and 8, 12, and 16 hours later during the continuous infusion. Initial blood flow was 6.0 +/- 0.7 ml/min per 100 g tissue (mean +/- SEM). After epidural bupivacaine, blood flow increased in all seven patients to 7.4 +/- 0.7 ml (P less than 0.02). Initial level of sensory analgesia was T4.5 +/- 0.17 (mean +/- SEM). Postoperatively, two patients maintained the initial level of sensory analgesia and low pain score throughout the 16-hour study. In these two patients epidural blood flow remained constant after the initial increase. Flow increased further to 10.3 +/- 0.8 ml/min per 100 g tissue (P less than 0.03) in the other five patients as the level of sensory analgesia regressed postoperatively. These data suggest that changes in epidural blood flow during continuous epidural infusion of bupivacaine, and thus changes in rates of vascular absorption of bupivacaine from the epidural space, may be an important factor contributing to differences in rates of regression of sensory analgesia.     

Epidural morphine improves pain relief and maintains sensory analgesia during continuous epidural bupivacaine after abdominal surgery

Twenty patients scheduled for elective major abdominal surgery were matched into two groups with regard to age, sex, height, body weight, and surgical procedure. Both groups received general anesthesia plus lumbar epidural analgesia with similar loading doses of bupivacaine 0.5% (23.1 +/- 1.0 and 23.3 +/- 0.8 ml) (mean +/- SEM) followed by continuous infusion of plain bupivacaine 0.5% (8 ml/hr) plus, in one group, epidural morphine (0.5 mg/hr). Pain score on a 5-point scale and sensory analgesia (pin prick) were assessed hourly for 16 hours after skin incision. If sensory analgesia decreased more than 5 segments from preoperative levels or if pain scores reached 2 (moderate pain), the patients were removed from the study, and pain was treated with other methods. Preoperative mean (+/- SEM) sensory levels of analgesia were similar in the bupivacaine and the bupivacaine-morphine groups (T3.4 +/- 0.5 and T3.3 +/- 0.4, respectively). In the group receiving only bupivacaine, sensory analgesia regressed over time with a simultaneous increase in pain score. Thus, within 10 hr after skin incision, seven patients in this group were discharged from the study, and 16 hr after incision only one patient maintained initial level of sensory analgesia. In contrast, each patient receiving bupivacaine plus morphine had stable sensory analgesia and was completely free of pain as indicated by a mean pain score of zero during the 16-hr observation period. Thus epidural morphine may improve pain relief and maintain analgesia during continuous epidural bupivacaine administration after abdominal surgery.     

Comparison of maternal satisfaction between epidural and spinal anesthesia for elective Cesarean section

PURPOSE: Epidural anesthesia was a commonly used technique for elective Cesarean section. Recently, because of the availability of non-cutting spinal needles, many institutions have changed from epidural to spinal anesthesia. The purpose of this study was to compare maternal satisfaction between epidural and spinal anesthesia for elective Cesarean section with a new satisfaction tool. METHODS: We studied healthy parturients in a randomized, double-blinded pilot study in which patients were assigned to receive either epidural (n = 13) or spinal (n = 14) anesthesia for elective Cesarean section. Two and 24 hr postoperatively, patients completed a validated 22-point maternal satisfaction questionnaire and a 10-cm visual analog score (VAS) for satisfaction. Maternal satisfaction scores were compared between groups. RESULTS: There was no difference in demographics, complications or technical failures between groups. Mean satisfaction scores on the questionnaire (0-154) at two and 24 hr were 130.23 +/- 11.36 and 129.54 +/- 16.70 for the epidural group and 116.92 +/- 18.47 and 115.92 +/- 15.71 for the spinal group (P = 0.04 and P = 0.03 respectively). No difference in VAS scores was noted. The presence of minor side effects including pruritus contributed to the lower satisfaction in the spinal group at 24 hr. CONCLUSION: This pilot study demonstrated higher maternal satisfaction with epidural than with spinal anesthesia for elective Cesarean section. This may be related to the increased side effects caused by neuraxial morphine. The satisfaction questionnaire was able to elucidate differences not detected with a global VAS for satisfaction. Further study with a larger patient population is required to confirm these data.     

Epidural neostigmine produces analgesia but also sedation in women after cesarean delivery

BACKGROUND: Intrathecal neostigmine produces analgesia but also nausea, limiting its utility. In contrast, epidural administration of neostigmine has been suggested to produce postoperative analgesia without nausea in nonpregnant patients. The purpose of this study was to examine the dose range for efficacy and side effects of epidural neostigmine in women at cesarean delivery receiving combined spinal-epidural anesthesia. METHODS: After institutional approval and informed consent, 80 patients for elective cesarean delivery were given combined spinal-epidural anesthesia with 8 mg hyperbaric bupivacaine plus 10 microg fentanyl. Patients were randomized to receive either saline or 75, 150, or 300 microg neostigmine (n = 20 per group) in 10 ml saline after cord clamping. Pain, morphine consumption, and side effects were monitored for 24 h. RESULTS: Global pain assessment for the first 24 h was reduced from 5.4 +/- 0.2 in the saline group to 3.0-3.5 +/- 0.3 in the neostigmine groups, dose independently. Correspondingly, global satisfaction with neostigmine was also improved (P < 0.05). Nausea and morphine consumption were similar among groups. Intraoperative shivering and sedation were increased in the 300-microg neostigmine group only (P < 0.05), and postoperative sedation was increased by neostigmine in a dose-independent fashion (P < 0.05). CONCLUSIONS: Epidural neostigmine produced modest analgesia in women after cesarean delivery. In contrast with previous reports, which focused primarily on nausea, these data suggest that epidural neostigmine can also produce mild sedation for several hours. These data suggest a limited role for single bolus-administration epidural neostigmine for analgesia after cesarean delivery. They also support future study of epidural neostigmine for obstetric analgesia.     

腰硬联合麻醉剖宫产术中布比卡因剂量的临床进展

布比卡因腰硬联合麻醉(combined spinal-epidural anesthesia,CSEA)在剖宫产中的应用较多,但其腰麻用于剖宫产术的最佳剂量较难确定,通过阅读文献发现有4种方法分别为给予小剂量腰麻,把腰麻限制在低位节段,通过硬膜外追加利多卡因来加强麻醉效果;根据身高与体重调节腰麻的剂量;通过硬膜外注射盐水来减少腰麻剂量;通过布比卡因腰麻复合阿片类药物来减少腰麻剂量,可使母体血液动力学相对稳定,副作用发生率低,麻醉效果好,但在这4种给药方法中,究竟哪一种能使剖宫产患者血液动力学最稳定、麻醉效果最好、副作用最少,还有待于进一步研究.