Isoflurane or halothane for cesarean section: comparative maternal and neonatal effects.

The maternal and neonatal effects of isoflurane and halothane combined with 50% N2O - 50% O2 were compared in 60 healthy parturients undergoing primary or repeat cesarean section. All patients had rapid sequence induction of anesthesia with sodium thiamylal 4 mg/kg followed by succinylcholine for tracheal intubation. Patients were randomly assigned to one of three groups of 20 each (inspired 0.5% isoflurane, 1% isoflurane or 0.5% halothane), combined with 50% N2O and O2. After delivery, 67% N2O in O2 was used, supplemented by butorphanol. Maternal blood loss did not differ significantly among the three groups and none of the patients developed intraoperative awareness. At the time of delivery, maternal plasma epinephrine levels were significantly above preinduction levels in the 0.5% isoflurane group but unchanged in the other two groups. Neonatal status as ascertained by Apgar scores, cord acid base status and the Neurologic and Adaptive Capacity Scores (NACS) was equally good in the three groups of patients. Serum inorganic fluoride concentrations in the mother after anesthesia were not significantly above preanesthetic levels in any of the groups and there was no biochemical evidence of renal toxicity. In all neonates fluoride ion concentrations in the first voided urine sample were less than 7 mumol/l, a value well below that associated with nephrotoxicity. It is concluded that isoflurane is a safe supplement to N2O - O2 mixture for cesarean section and is a safer alternative to halothane in situations when patients receiving beta-adrenergic therapy require cesarean section since halothane might potentiate arrhythmias caused by beta adrenergic agonists.

Bupivacaine/butorphanol/epinephrine for epidural anesthesia in obstetrics: maternal and neonatal effects.

The effects of epidural bupivacaine/butorphanol with and without 1:300,000 epinephrine on maternal analgesia, uterine activity, progress of labor, fetal heart rate, maternal blood pressure, newborn Apgar scores, neonatal acid base status and the neurologic and adaptive capacity scores (NACS) were compared in 33 parturients during labor and delivery. Patients in Group I (n = 17) received 0.25% bupivacaine plus 1 mg butorphanol plus 1:300,000 epinephrine, and those in Group II (n = 16) received the same agents without the epinephrine. Addition of epinephrine to bupivacaine/butorphanol did not have any adverse effects on uterine activity, duration of first or second stages of labor or fetal heart rate parameters. The incidence of maternal hypotensive episodes did not differ significantly between the two groups of patients. Apgar scores, neonatal acid base status and the NACS were equally good and did not differ significantly between the two groups. Duration of analgesia was significantly longer in Group I as compared to Group II patients (177.5 +/- 11 versus 131.8 +/- 10 minutes, p less than 0.01). It is concluded that addition of epinephrine 1:300,000 to bupivacaine/butorphanol during epidural anesthesia in the normal parturient has no adverse effects on the mother, fetus or neonate or on the progress of labor and it significantly prolongs the duration of analgesia.

Epidural morphine or butorphanol augments bupivacaine analgesia during labor.

To determine the efficacy and the safety of epidural morphine or butorphanol combined with bupivacaine, 40 healthy parturients were studied during labor and delivery. All patients received an epidural test dose of 2 ml of 0.5% bupivacaine. Patients were then randomly assigned to receive one of four epidural regimens in a double-blind fashion: 0.25% bupivacaine + 1 mg butorphanol (Group I), 0.25% bupivacaine + 2 mg butorphanol (Group II), 0.25% bupivacaine + 2 mg morphine (Group III), or 0.25% bupivacaine alone (Group IV). Each group consisted of ten patients. All subsequent epidural injections were with plain 0.25% bupivacaine. Duration of analgesia was significantly longer for groups I, II, and III when compared to group IV (p less than or equal to .01); 139 +/- 111, 141 +/- 14, 199 +/- 29, and 96 +/- 6 minutes, X +/- SEM respectively. Quality of analgesia was significantly better in groups I, II, and III when compared with group IV. There were no differences between groups in duration of first and second stages of labor, uterine activity, or method of delivery. Thirty percent of patients in the morphine group (group III) developed mild pruritus that did not require any treatment. All neonates were vigorous at 5 minutes and had good Apgar Scores, umbilical cord acid base status, and Neurological Adaptive Capacity Scores. The authors conclude that adding small doses of either morphine or butorphanol to epidural bupivacaine during labor is effective and safe. Butorphanol may be preferable since none of the patients experienced pruritus.

Mini-dose intrathecal morphine for the relief of post-cesarean section pain: safety, efficacy, and ventilatory responses to carbon dioxide.

To determine the safety, efficacy, and the ventilatory responses to carbon dioxide (CO2) of mini-dose intrathecal morphine, 33 healthy women who underwent cesarean section with spinal anesthesia using 0.75% bupivacaine in 8.25% dextrose were studied. Patients were randomly assigned to receive, in a double-blind fashion, either morphine 0.25 mg (group I, n = 11), morphine 0.1 mg (group II, n = 10), or saline (group III, placebo group, n = 12) in 0.5 ml volume mixed with the bupivacaine. In both groups I and II excellent postoperative analgesia with long duration was obtained (27.7 +/- 4.0 and 18.6 +/- 0.9 hours, respectively, X +/- SEM). All patients in group III required an analgesic (8 mg subcutaneous morphine) within 3 hours of spinal anesthesia. Seven patients in group I and four patients in group II developed mild pruritus that did not require treatment. Ventilatory responses to CO2 showed no evidence of depression attributable to either the 0.25 or 0.1 mg of morphine, but significant depression of the CO2 responses was observed in group III patients after administration of subcutaneous morphine. It is concluded that a dose as low as 0.1 mg of intrathecal morphine gives excellent analgesia with minimal to no side effects and that subcutaneous morphine is associated with marked depression of the ventilatory variables.