T. K. Abboud

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 tocarbon 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 longduration was obtained (27.7 ± 4.0 and 18.6 ± 0.9 hours, respectively, &OV0077; ± 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.

Maternal catecholamines decrease during labor after lumbar epidural anesthesia.

To determine whether epidural anesthesia during labor affects maternal circulating catecholamines, blood samples were obtained from 15 patients at the peak of and immediately after two consecutive painful contractions. A lumbar epidural local anesthetic without epinephrine was then administered. After the onset of analgesia, four blood samples were again drawn. All samples were analyzed by a radioenzymatic assay for epinephrine and norepinephrine concentrations. Before anesthesia, the mean (+/-SEM) plasma epinephrine level was 280 +/- 49 pg/ml, and the mean norepinephrine level was 866 +/- 122 pg/ml. After anesthesia, epinephrine levels decreased 56% (p less than 0.01). Although norepinephrine levels decreased approximately 19%, this reduction was not statistically significant. At the height of a contraction, catecholamine levels did not differ significantly from those occurring between contractions. Lumbar epidural anesthesia during labor reduces maternal epinephrine levels, probably by eliminating the psychological and physical stress associated with painful uterine contractions or by denervating the adrenal medulla. Whatever the mechanism, reducing pain and activity of the sympathetic nervous system should increase uterine blood flow.

Desflurane analgesia for vaginal delivery

The use of subanaesthetic concentration of inhalational anaesthetic for vaginal delivery offers many advantages to the mother and newborn‐ Desflurane, with the characteristics of rapid onset and minimal metabolism, may provide better analgesia and safety for labour pain control.

Pharmacokinetics, Placental Transfer, and Neonatal Effects of Vecuronium and Pancuronium Administered during Cesarean Section

Vecuronium and pancuronium were compared for placental transfer, pharmacokinetic variables, and neonatal effects during cesarean section under general anesthesia. Eighteen women underwent rapid-sequence intravenous induction using d-tubocurarine, succinylcholine, thiopental, and oxygen. Immediately after tracheal intubation, an intravenous injection of vecuronium (n = 11) or pancuronium (n = 7), 0.04 mg/kg, was given. Maternal venous blood samples were obtained before induction and at frequent intervals for 4 h after administration of vecuronium or pancuronium. Also, maternal venous and umbilical-cord arterial and venous blood samples were obtained at delivery. To describe placental transfer and maternal pharmacokinetics of the drugs, serum drug concentrations were determined using single-ion-monitoring mass spectrometry. The Apgar score and Neurologic and Adaptive Capacity Score (NACS) were used to evaluate neonatal condition. Both drugs crossed the placenta, as demonstrated by low concentrations of vecuronium (8.5-26.4 ng/ml) or pancuronium (12.2-34.2 ng/ml) found in umbilical venous blood. At delivery, the ratio of the drug concentration in umbilical venous blood to that in maternal venous blood was 0.11 +/- 0.02 for vecuronium and 0.19 +/- 0.03 for pancuronium. Vecuronium had a more rapid clearance (6.4 +/- 0.4 ml X kg-1 X min-1, mean +/- SE) and a shorter elimination half-life (36 +/- 1.8 min) than pancuronium (3.0 +/- 0.1 ml X kg-1 X min-1 and 72 +/- 6 min, respectively). No other pharmacokinetic differences were found between the drugs. Neonatal outcome was not affected adversely by either muscle relaxant, as assessed by Apgar scores and NACSs . The short duration of action, the minimal placental transfer, and the apparent lack of clinical neuromuscular effects on the newborn suggest that vecuronium should be a useful muscle relaxant for cesarean section.

Maternal, fetal, and neonatal responses after epidural anesthesia with Bupivacaine, 2-Chloroprocaine, or Lidocaine

The effects of epidural analgesia on fetal heart rate, fetal heart rate variability, uterine activity, maternal blood pressure, newborn Apgar scores, neonatal acid base status, and the early neonatal neurobehavioral status were studied in 150 parturients during labor and delivery. Group I (n = 50) received 0.5% bupivacaine, group II (n = 50) received 2% 2-chloroprocaine, and group III (n = 50) received 1.5% lidocaine. None of the three local anesthetics used had any significant effect on either base line fetal heart rate, beat-to-beat variability, or uterine activity. In cases in which monitoring of fetal heart rate was both technically satisfactory and continuous, late deceleration patterns were seen in 8 of 42, 0 of 34, and 3 of 47 of the fetuses in groups I. II, and III, respectively. The difference in incidence of late deceleration patterns between groups I and II was statistically significant (p < 0.025). Early neonatal neurobehavioral status did not differ among the three groups of neonates nor did any of the neonates in the three groups score lower than a control group of 20 neonates whose mothers did not receive any analgesia or medications for labor or delivery. It is concluded that epidural anesthesia as administered in this study has no significant effect on the base line fetal heart rate, uterine activity, or neurobehavioral status of the neonate, and that bupivacaine is associated with a higher incidence of what appears to be transient abnormalities of fetal heart rate.

Epidural Morphine for the Relief of Postoperative Pain after Cesarean Delivery

To determine the safety, efficacy, and dose response of epidurally administered morphine for analgesia after cesarean delivery, 40 healthy women who underwent cesarean delivery with epidural anesthesia were randomly assigned to receive one of four regimens for relief of postoperative pain: intramuscular administration of morphine, 7.5 mg (N = 10); or epidural administration of morphine, 2 mg (N = 10), 5 mg (N = 10), or 7.5 mg (N = 10). Evaluations were made of intensity and relief of pain, time to administration of additional analgesic medications, changes in vital signs and blood-gas tensions, and adverse effects. Intramuscular administration of 7.5 mg of morphine effectively relieved pain for only a short time. When morphine was administered epidurally, 2 mg proved ineffective whereas both 5 mg and 7.5 mg provided substantial pain relief for approximately 24 h. There were no significant changes in vital signs or blood-gas tensions. Side effects included pruritus and nausea, which occurred frequently but were usually mild and easily treated. We concluded that either 5 mg or 7.5 mg of morphine epidurally administered was effective and safe in providing prolonged analgesia after cesarean delivery.

Neonatal neurobehavioral effects of inhalation analgesia for vaginal delivery.

The authors studied the neonatal neurobehavioral effects of nitrous oxide: oxygen and enflurane: oxygen inhalation analgesia for vaginal delivery. Parturients were assigned randomly to receive no inhalation agent (Group 1, n = 21); enflurane, 0.3 to 0.8 per cent, and oxygen (Group 2, n = 22); or nitrous oxide, 30 to 50 per cent, and oxygen (Group 3, n = 18). Infants were tested at 15 min, 2 h, and 24 h of age using the Neurologic and Adaptive Capacity Score (NACS); and at 2 and 24 h using the Early Neonatal Neurobehavioral Scale (ENNS). No significant differences in neurobehavioral status occurred. For all groups, scores tended to be lowest at two hours of age. We conclude that neither enflurane nor nitrous oxide analgesia adversely affects neonatal neurobehavioral status at 15 min, 2 h, or 24 h of age.

Continuous infusion epidural analgesia in parturients receiving bupivacaine, chloroprocaine, or lidocaine--maternal, fetal, and neonatal effects.

: The effects of epidural analgesia for labor and delivery using a continuous infusion technique on fetal heart rate, uterine activity, maternal blood pressure, Apgar scores, neonatal acid-base status, and the Neurologic and Adaptive Capacity Scoring System were studied in 61 parturients. Group I (n = 23) received initial test and therapeutic doses of 2 and 6 ml of 0.5% bupivacaine followed by an infusion of 0.125% at a rate of 14 ml/hr. Group II (n = 19) received 2 and 6 ml of 2% chloroprocaine followed by an infusion of 0.75% at a rate of 27 ml/hr. Group III (n = 19) received 2 and 6 ml of 1.5% lidocaine followed by an infusion of 0.75% at a rate of 14 ml/hr. None of the three local anesthetics used had any significant effect on baseline fetal heart rate or uterine activity. In cases in which monitoring of fetal heart rate was both technically satisfactory and continuous, late and variable decelerations in fetal heart rate were seen in 10 of 17, 3 of 18, and 2 of 19 of the fetuses in groups I, II, and III, respectively. The incidence was significantly higher in group I than in groups II or III (P less than 0.05). Apgar scores and neonatal acid-base status were equally good in all three groups. Neurologic and adaptive capacity scores did not differ among the three groups of neonates, nor did any of the neonates in the three groups score lower than a control group of 19 neonates whose mothers did not receive any analgesia or medications for labor and delivery.(ABSTRACT TRUNCATED AT 250 WORDS)

Desflurane: a new volatile anesthetic for cesarean section. Maternal and neonatal effects.

Desflurane, a new volatile anesthetic agent with low blood/gas solubility, has recently been studied in clinical and animal trials but its use in obstetrics has not been adequately evaluated. This prospective study was undertaken to evaluate the maternal and neonatal effects of desflurane in obstetrical patients.

Epidural Butorphanol or Morphine for the Relief of Post-Cesarean Section Pain: Ventilatory Responses to Carbon Dioxide

To determine the safety, efficacy, and the ventilatory responses to carbon dioxide (CO2) of epidurally administered butorphanol or morphine, 122 healthy women who underwent cesarean section with epidural anesthesia were studied. Patients were randomly assigned to receive one of four epidural regimens for the relief of postoperative pain: 5 mg morphine (n = 32), 4 mg butorphanol (n = 30), 2 mg butorphanol (n = 29), or 1 mg butorphanol (n = 31). Epidural morphine provided satisfactory analgesia with slow onset and long duration of approximately 21 hr. When butorphanol was administered, analgesia of rapid onset was seen with increasing duration and effectiveness observed with increasing dose; approximately 8 hr when using 4 mg. Sixty-two percent of the patients who received morphine had pruritus. Somnolence was the main side effect encountered in patients who received epidural butorphanol. The ventilatory response to CO2 was depressed after morphine and after 2 and 4 mg butorphanol, but the duration of depression was more prolonged after morphine. It is concluded that epidural butorphanol is effective in providing pain relief after cesarean section with minor side effects. However, patients must be observed closely because of possible respiratory depression.