Comparison of Intrathecal Meperidine, Fentanyl, or Placebo Added to 0.5% Hyperbaric Bupivacaine for Cesarean Section / 대한마취과학회지

BACKGROUND: The addition of various opioids to 0.5% hyperbaric bupivacaine intrathecally seems to potentiate analgesic effects of bupivacaine and to prolong the duration of analgesia. We compared the effect of intrathecal meperidine 0.25 mg/kg and 0.5 mg/kg, fentanyl 0.15 microgram/kg, and placebo when administered together with 0.5% hyperbaric bupivacaine 9 mg for cesarean section. METHODS: Forty-four healthy term parturients were randomly allocated (n = 11 per group) to receive the test solution (1 ml) containing preservative-free normal saline (control group), fentanyl 0.15 microgram/kg, meperidine 0.25 mg/kg, or meperidine 0.5 mg/kg intrathecally, immediately followed by the injection of 0.5% hyperbaric bupivacaine 9 mg. We observed the effective postoperative analgesic duration (time to VAS > or = 4), quality of anesthesia and side effects. RESULTS: The effective postoperative analgesic duration significantly increased in the groups receiving opioid compared with the control group (P < 0.05); control group 101.4 +/- 28.6 min; fentanyl group 192.3 +/- 29.2 min; meperidine 0.25 mg/kg group 208.8 +/- 21.7 min; meperidine 0.5 mg/kg group 289.8 53.6 min (data expressed as mean +/- SD). The quality of anesthesia was excellent in 100% of the meperidine group but in 82% of the fentanyl group and 91% of the control group. The incidence of nausea and vomiting were higher in the meperidine 0.5 mg/kg group (73%) than in the remaining groups (P < 0.05). CONCLUSIONS: The addition of fentanyl 0.15 microgram/kg or meperidine 0.25 mg/kg to 0.5% hyperbaric bupivacaine 9 mg for spinal anesthesia improves intraoperative analgesia and provides analgesia into the immediate postoperative period with no adverse effects on mother or neonate.

The Effect of Prior Dural Puncture with a 27G Spinal Needle on Epidural Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: If started with segmental block, epidural anesthesia appears to have an inadequate sacral block in the early part of cesarean deliveries. A dural puncture using the combined spinal-epidural technique making an early sacral blockade might be a solution. METHODS: A prospective, randomized, double-blinded study was performed on forty patients who were divided into two groups (C, DP; n = 20, each). An epidural infusion of 25 ml of 2% lidocaine with epinephrine was given to the group C. A dural puncture with a 27G Whitacre needle was done before the epidural infusion in the group DP. Two-way sensory levels were checked for 15 min, just before the operation. The side effects and recovery variables were also compared between the groups. RESULTS: Initial wider cephalic block (P = 0.038, 0 min) followed by more caudal block (P = 0.023, 0.013; 5, 10 min after the completion of the epidural infusion, respectively) occurred in the DP group. After 10 min, there were no differences in both block levels. The number of dermatomes blocked was bigger in the DP group at 10 min after. Fewer patients in the DP group had nausea and/or vomiting (P = 0.044). CONCLUSIONS: Early spread of the sensory blockade, initial cephalic and then caudal, was due to the dural puncture by a 27G needle. This fast onset could make the parturients more comfortable in the early part of cesarean sections.

The Effects of Epidural "Top-up" on Spinal Block during Combined Spinal Epidural Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: Epidural "top-up" has been known to enhance spinal anesthesia in combined spinal-epidural anesthesia. Saline and local anesthetics were reported to have a volume effect when infused as epidural "top-up". In cesarean deliveries where high sensory block has been achieved using a combined spinal-epidural technique, we evaluated the effects of epidural "top-up" on the underlying spinal block. METHODS: Sixty-six parturients were allocated randomly into group C (control, n = 21), S (saline, n = 21), or B (bupivacaine, n = 24). Ten minutes after they received 8 mg of 0.5% hyperbaric bupivacaine intrathecally, nothing, 10 ml saline, or 10 ml of 0.25% bupivacaine were infused, respectively. The sensory level at 10 min, the maximal level and the time to reach it, and degrees of motor block and muscle relaxation were compared. We also investigated intraoperative side effects and postoperative findings in the PACU. RESULTS: There were significant changes in sensory level after epidural top-ups in the group S and B, but no differences in maximal height of sensory block and degree of muscle relaxation among the groups. Intraoperative pain was complained in fewer patients in the group B. Times to sensory and motor recovery were longer in patients of the group B. CONCLUSIONS: Eight milligrams of hyperbaric bupivacaine using a combined spinal-epidural technique was not sufficient for cesarean section. Epidural saline top-up showed volume effect, which didn't improve the spinal block. Epidural "top-up" of 0.25% 10 ml bupivacaine enhanced the spinal block and sustained the block postoperatively.

The Effect of Different Route of Preanesthetic Ranitidine on Gastric Acidity in Patients Undergoing Elective Cesarean Section / 대한마취과학회지

BACKGROUND: Aspiration of gastric contents is an ever -present risk in the use of general anesthesia, particularly in emergency and obstetric situations, and morbidity and mortality associated with this complication increases with the volume and acidity of the aspirate. Since direct inhibition of acid secretion may be a preferable method, we studied the effectiveness of ranitidine in increasing gastric pH. METHODS: Sixty patients scheduled for elective cesarean section under general anesthesia before midday were randomly divided into three groups. The control group (n=20) did not received preanesthetic ranitidine. Group I (n=20) received a slow intravenous injection of 50 mg ranitidine, one hour before surgery. Group II (n=20) received 150 mg ranitidine orally, both the night before surgery and the morning of surgery. RESULTS: Compared with the control group, the mean gastric pH increased significantly in group I and II (P<0.05). There was no significant difference of gastric pH between group I and II. CONCLUSIONS: The results of this study indicate that ranitidine is a useful agent in increasing the gastric pH in women undergoing elective cesarean section. Ranitidine administered intravenously and orally were equally effective means in increasing the gastric pH.

Adequate Target Concentration of Propofol and Fentanyl for Total Intravenous Anesthesia by Target-controlled Infusion during Cesarean Section / 대한마취과학회지

BACKGROUND: Propofol has been used for the induction and maintenance of obstetric anesthesia for its potential benefit of rapid recovery and less post-anesthetic complications. In order to determine the safe application of target-controlled infusion of propofol and fentanyl during Cesarean section under general anesthesia, we have investigated the adequate target concentrations of each drug using the bispectral index and hemodynamic parameters. METHODS: Ninety-two pregnant women who received Cesarean section under general anesthesia were enrolled in this study. After preoxygenation, anesthesia was induced with thiopental 4 mg/kg and succinylcholine 1 mg/kg, and intubation was done. Vecuronium 0.1mg/kg I.V. was applied for muscle relaxation, and mechanical ventilation was maintained with N2O/O2 (2 L/2 L)-enflurane. EtCO2 was maintained between 30 35 mmHg. After delivery of the fetus, propofol and fentanyl was infused by a computer-assisted continuous infusion system with air/O2 (2 L/2 L). The bispectral index was monitored perioperatively. This study proceeded in three stages. In the first stage, thirty women were studied for titration of the target effect-site concentration of propofol that could maintain a bispectral index between 40 60 while maintaining the target concentration of fentanyl at 1.5 ng/ml. In the second stage, forty-two women were randomly assigned into the four different groups (F25, F50, F75, F100) at target fentanyl concentrations of fentanyl of 0.25, 0.50, 0.75 and 1.0 ng/ml for each group respectively. The adequate target concentration of fentanyl was titrated. In the third stage, twenty women were studied for assessment of the adequacy of target concentrations of propofol and fentanyl prospectively. RESULTS: The target effect-site concentrations (Ce, 95% confidence interval) that could maintain 50% and 95% of patients hemodynamically stable with the bispectral index within 40-60 were 2.41 (2.27-2.55) microgram/ml and 3.15 (2.95-3.50) microgram/ml for propofol, 0.32 (0.13-0.46) ng/ml and 0.84 (0.66-1.29) ng/ml for fentanyl. The pre-anesthetic bispectral index was 97.1+/-1.2 and it decreased maximally to 39.5+/-6.47 after thiopental injection and increased maximally to 83.6+/-6.3 before delivery and it was 80.6+/-6.9 for eye-open to verbal command during recovery. CONCLUSIONS: The adequate target effect-site concentrations of propofol and fentanyl for the maintenance of total intravenous anesthesia during Cesarean section were determined and these concentrations were validated prospectively.

Comparison of Combined Spinal Epidural Anesthesia and Epidural Anesthesia for Cesarean Section / 대한마취과학회지

BACKGROUND: Epidural anesthesia (EA) has become most popular for cesarean section, but has some drawbacks such as incomplete block, inadequate muscle relaxation and delayed onset. Combined spinal epidural anesthesia (CSEA) has gained an increasing interest as it combines a reliability of the spinal block and the flexibility of an epidural block. We investigated the efficacy of CSEA which combines main spinal and supporting epidural anesthesia, comparing with pH adjusted EA, for cesarean section. METHODS: Sixty four pregnant women at full term were divided into two groups. Group 1 (n=32) received CSEA with 1.5~1.6 ml of 0.5% hyperbaric bupivacaine intrathecally, followed 10 minutes after by 10 ml of 0.25% plain bupivacaine through the epidural catheter. Group 2 (n=32) received EA with 20~25 ml of 2% lidocaine which was added 0.1 ml of 0.1% epinephrine, 100 microgram of fentanyl and 1.5 ml of 8.4% sodium bicarbonate. The quality and side effects of surgical anesthesia, neonatal state and postoperative course were compared between two groups. RESULTS: While 22% (7 cases) of Group 2 complained of intraoperative pain but none of Group 1 did (p=0.011). Muscle relaxation and motor block were much better in group 1 (p<0.001 and p=0.011 each). Significantly more women in group 2 had shivering (p=0.001) and they also had nausea and vomiting more, though that difference is not significant. Not only time to T4 (9.7 vs. 8.3 min., mean, p<0.001), but also stay at PACU, recovery of sensory and motor block and start of postoperative pain were all significantly shorter in Group 1. None of both groups had post-dural puncture headache (PDPH). CONCLUSIONS: We can conclude that CSEA, when combining main spinal and supporting epidural anesthesia, has greater efficacy and less side effects for cesarean section than pH adjusted EA.