J. B. Weiss

Neurobehavioral Responses and Drug Concentrations in Newborns after Maternal Epidural Anesthesia with Bupivacaine

The neurobehavioral status of 20 newborn infants was evaluated after two to four hours of life following maternal epidural anesthesia with hupivacaine for labor and vaginal delivery. All infants were normal products of uncomplicated full-term gestations. The 20 infants, whose mothers had received continuous lumbar epidural anesthesia with bupivacaine. demonstrated no measurable difference from control infants and did not have the decrease in muscle tone and strength observed in infants whose mothers had received continous lumbar epidural anesthesia with lidocaine or mepivacaine in a previous study.

Comparison of the maternal and neonatal effects of halothane, enflurane, and isoflurane for cesarean delivery.

: The maternal and neonatal effects of 50% O2-50% N2O alone and 50% O2-50% N2O combined with 0.5% halothane, 1.0% enflurane, or 0.75% isoflurane were studied in 42 healthy parturients undergoing general anesthesia for elective primary or repeat cesarean delivery at term. All patients received thiopental and succinylcholine for induction and were intubated and ventilated with a tidal volume of 10 ml/kg at a rate of 10 breaths/min. Two of 12 (17%) patients given O2-N2O alone had recall; none who received a potent inhalation agent had any recall. Blood loss was similar in all four groups. There were no significant differences between groups in induction-to-delivery and uterine incision-to-delivery intervals, the frequency of Apgar scores less than 7 at 1 and 5 min, maternal and fetal blood-gas tensions, acid-base balance, lactate values, and early neonatal neurobehavioral scores at 2-4 h. It is concluded that analgesic concentrations of halothane, enflurane, and isoflurane can be safely added to 50% O2-50% N2O to prevent maternal awareness during general anesthesia for cesarean delivery while maintaining normal maternal and neonatal conditions.

Epidural anesthesia for cesarean section in diabetic parturients: maternal and neonatal acid-base status and bupivacaine concentration.

: Acid-base status and blood levels of bupivacaine were determined in 16 diabetic parturients and their infants after epidural anesthesia for cesarean section. The newborn infants were divided into two groups based on umbilical artery pH at birth. Group A consisted of 10 infants who had a pH of less than 7.2 and group B consisted of six infants with a pH of greater than 7.2. Neonatal acidosis was related to both the severity of maternal diabetes and the presence of maternal hypotension after epidural anesthesia. In addition, the half-life to bupivacaine was prolonged in acidotic infants. The placental transfer of bupivacaine, as judged by umbilical vein/maternal vein ratios, was significantly greater in acidotic infants.

Epidural Anesthesia for Cesarean Section±A Comparison of Bupivacaine, Chloroprocaine, and Etidocaine

: The authors studied three groups of patients undergoing elective cesarean section during lumbar epidural anesthesia with bupivacaine, 0.75 per cent (15 patients), chloroprocaine, 3 per cent (15 patients) or etidocaine, 1 per cent (ten patients). Excellent sensory and motor block were obtained with chloroprocaine and bupivacaine; sensory anesthesia was inadequate with etidocaine in most patients. Onset of anesthesia, induction--delivery interval, and stay in the recovery room were all longer with bupivacaine when compared with chloroprocaine. Fetal outcomes, as determined by Apgar scores, acid--base status and neurobehavioral testing, were equally good in all groups. At delivery, fetal/maternal concentration ratio of bupivacaine was 0.31 and that of etidocaine, 0.25. The umbilical artery--umbilical vein blood concentration difference for etidocaine was significantly higher than that for bupivacaine. Excellent clinical results were obtained using either bupivacaine, 0.75 per cent, alone, or chloroprocaine, 3 per cent- for induction and maintenance of anesthesia, supplemented with bupivacaine, 0.25 per cent, before removal of the catheter.

Effects of Maternal Position on Epidural Anesthesia for Cesarean Section, Acid—Base Status, and Bupivacaine Concentrations at Delivery

: In 25 patients excellent clinical anesthesia for elective cesarean section was obtained with lumbar epidural block using an average dose of bupivacaine of 130 mg (18 ml of 0.75 per cent solution). Supplemental drugs were not needed. All infants had normal Apgar scores at delivery. Ten patients were kept in a 35--40 degree semi-sitting supine position during induction, while 15 patients were similarly semi-sitting but turned into the left lateral position. Maternal position did not affect the adequacy of the anesthesia or the clinical condition of the infants, but did alter acid-base state and bupivacaine concentrations in the infants. At delivery, the infants whose mothers had been supine had significantly lower pH values in umbilical cord blood than those whose mothers had been in the lateral position. Also, high concentrations of bupivacaine were found in the umbilical vein blood of infants whose mothers were supine.

Anesthetic-related maternal mortality, 1954 to 1985

This is a population-based study of the safety of obstetrical anesthesia in the Commonwealth of Massachusetts between 1954 and 1985. We used data collected by the state Committee on Maternal Mortality, which was founded in 1941. There were a total of 37 maternal deaths during the study period due to anesthetic-related complications. During the same time period, there were 886 maternal deaths. Thus, anesthetic-related mortality comprised 4.2% of all deaths, and the mortality rate was 1.5 per 100,000 live births between 1955 and 1964, 1.5 per 100,000 live births between 1965 and 1974, and 0.4 per 100,000 live births between 1975 and 1984. In the first decade of this study, aspiration during administration of a mask anesthetic was the primary cause of death. During the second decade, cardiovascular collapse associated with regional anesthesia was the primary cause of death. During the last decade of this study, all deaths were associated with general endotracheal anesthesia. As a result of this study and having identified the changes in the standard of care in Massachusetts that led to the reduction in maternal mortality, we offer recommendations to further improve the safety of anesthesia for childbirth in this country.

Acid-base status of diabetic mothers and their infants following spinal anesthesia for cesarean section.

: Acid-base status and Apgar scores were evaluated in 10 rigidly controlled insulin-dependent diabetic mothers and 10 healthy nondiabetic control women having spinal anesthesia for cesarean section. Dextrose-free intravenous solutions were used for volume expansion before induction of anesthesia, and hypotension was prevented in all cases by prompt treatment with ephedrine. There were no significant differences in the acid-base values between the diabetic and nondiabetic mothers and the infants of the diabetic and control group. Apgar scores were also similar in the two groups. If maternal diabetes is well controlled, if dextrose-containing solutions are not used for maternal intravascular volume expansion before delivery, and if maternal hypotension is avoided, spinal anesthesia can be used safely for diabetic mothers having cesarean section.

Blood concentration of mepivacaine and lidocaine in mother and baby after epidural anesthesia

Abstract The concentration of mepivacaine and lidocaine in mother and neonate was assayed by means of gas liquid chromatography. There was a rapid appearance of the drug in the maternal circulation, mean peak concentration being attained within 5 minutes. In 19 cases of mepivacaine anesthesia the mean maternal blood concentration was 2.2 μg per milliliter, whereas in the neonate the mean concentration was 1.6 μg per milliliter. In 13 cases of lidocaine anesthesia the mean maternal blood concentration was 2.2 μg per milliliter and in the neonate 1.55 μg per milliliter. Three neonates required resuscitation and in these cases the duration of anesthesia was greater than 6 hours with a total dosage of anesthetic agent greater than 600 mg. The mothers showed no side effects attributable to the anesthetic agents.

An effect of succinylcholine on the uterus: Clinical observations

Abstract A clinical study of 70 obstetrical patients in whom increased uterine tone interfered with the second or third stage of labor has been presented. Succinylcholine was administered to these patients, and its effect on uterine musculature was evaluated. Succinylcholine produced useful uterine relaxation. A definite dose-response relationship was demonstrated. A correlation between the effect of succinylcholine on the uterine musculature and on the smooth muscles of the eye and the blood vessels has been indicated. The potential complications of the use of succinylcholine in obstetrics have been discussed.

Maternal acid-base status and neonatal respiratory distress in normal and complicated pregnancies

Abstract In order to investigate the possible etiological importance of maternal blood-gas and acid-base status in the respiratory distress syndrome, studies were made on the arterial blood of mothers at delivery and on cord and on 1 hour arterial samples of their infants. A total of 79 maternal samples, 76 cord bloods, and 30 1 hour infant samples were studied. The maternal blood data indicated that neither maternal hypoxia nor acidosis at delivery was etiologycally important in the 14 infants who developed respiratory distress. Moreover, clinical and cord blood biochemical studies also suggested that the presence of intrauterine asphyxia as deduced from such information was not an important etiological factor in this syndrome. Infant arterial samples suggested that maternal metabolic acidosis, when present, was associated with acidosis in the infant which persisted at least 1 hour.