[Epidural anesthesia using the bupivacaine-fentanyl combination for cesarean section]

Efficacy of sufentanil addition to ropivacaine epidural anaesthesia for Caesarean section

BACKGROUND

This prospective double-blind trial evaluated the effect of sufentanil addition to epidural ropivacaine for elective Caesarean section.

METHODS

Sixty healthy parturients were randomly assigned to receive an initial dose of 90 mg of plain ropivacaine, or 90 mg of ropivacaine plus 10 or 20 microg of sufentanil (n = 20 each). Before surgery, if necessary, additional epidural ropivacaine was injected. Primary outcome parameter was time to achieve sensory block at T4.

RESULTS

Time to reach the sensory block was remarkably reduced (P < 0.001 each) by addition of 10 or 20 microg of sufentanil (21 +/- 8 min, 15 +/- 5 min, 11 +/- 4 min in the plain ropivacaine, the 10- and 20-microg sufentanil groups, respectively) whereas the visual analogue scale (VAS) scores at delivery were significantly reduced (P = 0.028) only by 20 microg of sufentanil (32 +/- 35 mm in the plain ropivacaine vs. 9 +/- 19 mm in the 20-microg sufentanil groups). The total dose of ropivacaine was significantly lower (P = 0.005) in patients receiving 20 microg of sufentanil (100.5 +/- 15.0 mg) compared with those treated with plain ropivacaine (118.5 +/- 17.3 mg). The incidence of maternal side-effects (hypotension, bradycardia, nausea, vomiting, shivering, pruritus) and neonatal outcome [APGAR score, neurologic and adaptive capacity (NAC) score, umbilical cord blood-gas values] did not differ between the groups.

CONCLUSION

Our results suggest that addition of 20 microg of sufentanil improved the epidural anaesthesia with ropivacaine 0.75% for Caesarean section.

Epidural ropivacaine 1% with and without sufentanil addition for Caesarean section

BACKGROUND

So far only ropivacaine concentrations of 0.5 and 0.75% have been used for Caesarean section. This prospective double-blind trial evaluated the anaesthetic quality of ropivacaine 1% with and without sufentanil addition.

METHODS

Three groups of patients (n=20 each) scheduled for an elective Caesarean section were studied. The patients received initially 120 mg ropivacaine, or 120 mg ropivacaine plus 10 microg or 20 microg sufentanil. Additional epidural ropivacaine was injected if necessary. Primary outcome parameter was time to achieve sensory block at T4. Moreover, pain intensity at delivery (visual analogue scale, VAS), incidence of maternal side-effects (hypotension, bradycardia, nausea, vomiting, shivering, pruritus), and neonatal outcome (Apgar score, neurologic and adaptive capacity score, umbilical cord blood-gas values) were recorded.

RESULTS

The onset time for the sensory block was not significantly different among the groups. Also, VAS scores at delivery did not differ significantly between the plain ropivacaine 1% group (18 +/- 29 mm), the 10-microg sufentanil group (1 +/- 5 mm), and the 20-microg sufentanil group (6 +/- 18 mm). The total dose of ropivacaine was significantly higher in the plain ropivacaine 1% group (145 +/- 19 mg) compared to the patients receiving additional 10 microg sufentanil (130 +/- 15 mg, P = 0.02) or 20 microg sufentanil (129 +/- 16 mg, P = 0.01). The incidence of maternal side-effects and neonatal outcome were similar in all groups.

CONCLUSION

Ropivacaine 1% alone provided sufficient analgesia. Sufentanil addition did not significantly improve the quality of epidural anaesthesia with ropivacaine 1.0% for Caesarean section.

Epidural fentanyl, adrenaline and clonidine as adjuvants to local anaesthetics for surgical analgesia: meta-analyses of analgesia and side-effects

BACKGROUND

The risk/benefit ratio of adding fentanyl, adrenaline and clonidine to epidural local anaesthetics for improving intraoperative analgesia is unclear. This meta-analysis was performed to clarify this issue.

METHODS

Trials retrieved by search were considered if they were prospective, controlled, epidural analgesia (without combining general anaesthesia) was planned and occurrence of pain during surgery or side-effects were reported. Papers entered meta-analysis if they reached a predefined minimum quality score. Pooled odds ratios (OR) and confidence intervals (CI) were computed. P < 0.05 was considered as significant.

RESULTS

Eighteen trials were included in the analysis for fentanyl. Fentanyl decreased the likelihood of pain (OR = 0.21, 95% CI = 0.15-0.30, P < 0.001) and increased the incidence of pruritus (OR = 5.59, 95% CI = 3.12-10.05, P < 0.001) and sedation (OR = 1.88, 95% CI = 1.19-2.98, P = 0.003), compared to control (local anaesthetic without fentanyl). Fentanyl had no effect on respiratory depression, nausea, vomiting and Apgar score. One case of respiratory depression of a newborn was observed. Because of the very low number of trials selected, evaluation of adrenaline and clonidine was not feasible.

CONCLUSION

The analysis of current literature shows that the addition of fentanyl to local anaesthetics for intraoperative epidural analgesia is safe and advantageous. The reduction in the incidence of pain during surgery is quantitatively high and therefore clinically significant. Side-effects are mild. Randomized, controlled trials have to be performed in order to clarify the role of adrenaline and clonidine as epidural adjuvants for surgical analgesia.

Effect of adrenaline on plasma concentrations of fentanyl during epidural anaesthesia for caesarean section

The present study was designed to assess the effect of adrenaline on the plasma concentrations of fentanyl in mothers and umbilical vessels after epidural administration for caesarean section. Thirty patients undergoing elective caesarean section were allocated randomly into two groups. Group 1 (n = 16) received 100 microg fentanyl, 10 ml of 0.5% bupivacaine and 10 ml 2% lidocaine, while group II (n = 14) received 100 microg fentanyl, 10 ml of 0.5% bupivacaine with adrenaline 1:200 000, and 10 ml of 2% lidocaine with adrenaline 1:80 000. Blood samples were obtained from the maternal antecubital vein (MV) at various times up to 6 hours after epidural injection, and from umbilical vein (UV) and arteries (UA) at birth for determination of plasma fentanyl by radioimmunoassay. Fentanyl Cmax and Tmax in MV did not differ significantly between the two groups. In umbilical vessels, plasma fentanyl concentrations were comparable in the two groups: (0.12 +/- 0.08 ng ml(-1) and 0.13 +/- 0.08 ng ml(-1) in UV and 0.08 +/- 0.07 ng ml(-1) and 0.06 +/- 0.05 ng ml(1) in UA of groups I and II respectively). The maximum plasma concentration in UV was 0.24 ng ml(-1) in group I and 0.25 ng ml(-1) in group II. There was no significant correlation between umbilical vessel (vein or artery):MV ratio and dose to delivery interval and no difference between the two groups in Apgar score or umbilical cord pH.

Neonatal effects of adding epidural fentanyl to 0.5% bupivacaine for caesarean section

Epidural injection of opioids has been introduced to improve analgesia during labour and caesarean section. This study was designed to quantify placental transfer of fentanyl and to evaluate neonatal effects of adding fentanyl to 0.5% bupivacaine for epidural anaesthesia in women undergoing elective caesarean section at term. The parturients were randomly allocated to one of four groups of 20, who received either saline (control) or 50, 75 or 100 microg of fentanyl added to 20 ml of 0.5% bupivacaine. Apgar scores, time to sustained respiration and umbilical acid-base values did not differ among the groups. The median (interquartile range) umbilical artery to maternal vein fentanyl concentration ratio was 0.34 (0.26-0.48) when the fentanyl groups were taken together. Neurologic and adaptive capacity scores were evaluated at 2 and 24 h. Neonates whose mothers received fentanyl had lower scores with regard to supporting reaction at 2 h and active tone at 24 h, when compared to controls (P<0.05), but there were no differences among the groups with regard to the other test criteria in the neurobehavioural test. In conclusion, epidural injection of fentanyl 50-100 microg did not produce depression of the term neonate.

Maternal effects of adding epidural fentanyl to 0.5% bupivacaine for caesarean section

Epidural injection of fentanyl added to 0.5% bupivacaine improves epidural anaesthesia during caesarean section. The present prospective randomized double-blind study sought to determine the lowest effective dose of fentanyl. Eighty healthy women at term were divided into four groups of 20, with each group receiving a different 2 ml study solution: saline (control) or 50, 75 or 100 microg of fentanyl added to 20 ml of 0.5% bupivacaine. Additional increments of 0.5% bupivacaine were administered as required at 30 min and onwards until a bilateral block to T4 was attained. The onset, duration and segmental level of analgesia, and degree and duration of motor block were not influenced by the addition of fentanyl. Peroperative quality of analgesia was improved, as the request for supplementary analgesics was less following the addition of 75 or 100 microg of fentanyl (P < 0.05). Postoperatively the time to first supplemental opioid request was prolonged and pain was reduced for at least 6 h from induction of anaesthesia when 75 or 100 microg of fentanyl had been added (P < 0.05). Pruritus was the only side-effect (P < 0.05). In conclusion, fentanyl 75 microg was the lowest effective dose for improving quality of analgesia. Onset time was not reduced by the addition of fentanyl.

Maternal and umbilical cord concentrations of fentanyl after epidural analgesia for cesarean section

The maternal and umbilical concentrations of fentanyl were measured after epidural analgesia for cesarean section, using a highly sensitive radioimmunoassay method. Sixteen parturients were anesthetized with a single epidural injection of a mixture of 85 mg bupivacaine 0.5%, 60 mg etidocaine 1%, and 100 micrograms fentanyl with epinephrine 1:200,000. Apparent maternal individual maximum peak concentration (Cmax) of fentanyl was 0.38 +/- 0.16 ng/ml (mean +/- SD) (range 0.12-0.59 ng/ml) and the time to reach Cmax (Tmax) was 24 +/- 14 min (range 5-60 min). Infants were born 19 to 42 min after epidural administration of fentanyl (mean 27 min). Fentanyl concentrations in neonates was 0.13 +/- 0.04 ng/ml for the umbilical vein and 0.06 +/- 0.03 ng/ml for the artery. The fetus extraction ratio was 53 +/- 19% (range 20-83%). The large difference between arterial and venous concentrations of fentanyl may be due to a metabolization by the fetus and/or an uptake of the drug in the fetal tissues. Thus, even if fentanyl levels reaching the fetus after cesarean section under epidural anesthesia, using local anesthetics with 100 micrograms of fentanyl, are within safe range values, the likelihood of fentanyl uptake by fetal tissues calls for a cautious use of repeated fentanyl administration.

Maternal and neonatal effects of adding epidural sufentanil to 0.5% bupivacaine for cesarean delivery

STUDY OBJECTIVE

To determine the maternal and fetal effects of the addition of epidural sufentanil to 0.5% bupivacaine for cesarean delivery.

DESIGN

Randomized, double-blind, prospective study.

SETTING

University Hospitals, Katholieke Universiteit Leuven, Leuven, Belgium.

PATIENTS

Sixty women at term scheduled for elective cesarean section, all of whom had elected epidural anesthesia.

INTERVENTIONS

The 60 women were divided into three groups of 20, with each group receiving a different 1 ml study solution: saline (control) or sufentanil 20 micrograms or sufentanil 30 micrograms added to 0.5% bupivacaine and epinephrine (1:200,000).

MEASUREMENTS AND MAIN RESULTS

In the mother, the quality of anesthesia, the duration of postoperative analgesia, the volume of anesthetic, and the frequency of side effects were examined. The neonates were evaluated at 5 and 10 minutes after birth by Apgar scores and between 60 and 120 minutes after birth by both the screening test developed by Prechtl and the Neurological and Adaptive Capacity Scoring System. Immediately after delivery, maternal and umbilical vein blood were drawn and assayed for sufentanil levels. Adding sufentanil significantly improved the quality of anesthesia without depressing the neurobehavioral status of the baby.

CONCLUSION

The epidural injection of sufentanil added to 0.5% bupivacaine with epinephrine improved the quality of anesthesia during elective cesarean section without jeopardizing the safety of the baby.

Spinal opioids in the management of obstetric pain

Spinal opioids have become increasingly popular agents for providing analgesia during labor, augmenting anesthesia during cesarean section, and providing pain relief after operative delivery. The development of spinal opioids in the management of obstetric pain is reviewed.

A double-blind comparison of epidural bupivacaine and bupivacaine-fentanyl for caesarean section

The effect of adding fentanyl 100 mcg to bupivacaine 0.5% plain to establish epidural anaesthesia for elective caesarean section was investigated in a randomised, double-blind study of sixty healthy women. The quality of intraoperative analgesia as assessed by both patients and anaesthetists was significantly improved with fentanyl. The onset and duration of sensory anaesthesia, degree and duration of motor block, and other characteristics of epidural anaesthesia were unaltered. No adverse maternal side-effects (except mild pruritus) were noted and neonatal outcome was unaffected. The pharmacokinetics of epidural fentanyl administration were investigated by plasma fentanyl assays from maternal and cord blood taken at delivery. Epidural bupivacaine-fentanyl combination is a valuable therapeutic approach to the conduct of epidural anaesthesia for caesarean section in healthy women and foetuses. Further neonatal evaluation of the premature or compromised foetus is suggested before the universal application of this technique.

Onset of action between bupivacaine 0.5% and bupivacaine 0.5% plus fentanyl 75 mcg

This study tested the hypothesis that the addition of fentanyl 75 mcg to bupivacaine 0.5% at the onset of epidural anesthesia for cesarean section reduces the onset time for T4 sensory blockade. The study was conducted in a randomized, double-blind fashion. The same observer performed sensory testing using pain to pinprick. Fourteen ASA I patients scheduled for elective cesarean section had epidural catheters placed. Group 1 (n = 7) received bupivacaine 0.5%, and group 2 (n = 7) received bupivacaine 0.5% plus fentanyl 75 mcg. Patients 5'0'' to 5'4'' in height received 15 ml, and patients 5'5'' to 5'9'' received 20 ml of bupivacaine. There were no adverse effects on the neonate or clinically important changes in maternal hemodynamics. The maternal age, height, weight, and bupivacaine dose did not differ between groups (p greater than 0.05). For group 1, the mean times for sensory loss at T7, T6, T5, and T4 were 13.1 +/- 3.8 minutes, 15.0 +/- 4.0 minutes, 16.9 +/- 4.3 minutes, and 19.3 +/- 4.9 minutes, respectively; for group 2, the mean times were 8.1 +/- 0.9 minutes, 9.9 +/- 1.1 minutes, 11.3 +/- 1.5 minutes, and 12.7 +/- 2.0 minutes, respectively. Two-factor analysis of variance between groups 1 and 2 showed a significant difference (p less than 0.0001), representing a 35% reduction of mean onset time. The coefficient of variation of the mean onset times for group 1 subjects was 26.6% +/- 1.7% and for group 2 subjects 12.7% +/- 2.2% (p less than 0.001), representing a 50% reduction in between-subject variation.(ABSTRACT TRUNCATED AT 250 WORDS)

[Use of epidural and intrathecal opiates in obstetrics]

The discovery of opiate receptors and naturally occurring opiate-like substances in the central nervous system started a new era in pain control. Epidural and spinal opiates have been increasingly used since 1979. However, applying these analgesic techniques in obstetrics has been criticized because of possible side-effects on the mother and foetus. In this literature survey, their advantages and disadvantages are analyzed. Maternal side-effects include pruritus, nausea, urinary retention, and, most of all, respiratory depression. As a general rule, these side-effects are greater with the intrathecal route, high doses, and the use of morphine. The effects on the course of labour are small, and neonatal status is not altered. Spinal and epidural opiates are efficient analgesic techniques for labour and caesarean section. They provide a dose-related, but not surgical, analgesia. Currently, there is a great deal of interest in mixtures of a diluted local anaesthetic agent and a lipophilic drug for use during labour or caesarean section. An opiate alone may not consistently provide satisfactory analgesia during labour, and it cannot be recommended for routine use, except for patients in whom the cardiovascular effects of routine regional anaesthesia are to be avoided. The choice of a lipid-soluble opiate like fentanyl is safe. However, when considering new drugs, great care must be taken to avoid unforeseen problems. A good knowledge of the problem and a cautious approach combined with careful monitoring of the respiratory rate and adequacy of ventilation are the keys to the safe use of spinal and epidural opiates.

[Epidural anesthesia during labor: comparison of 3 combinations of fentanyl-bupivacaine and bupivacaine alone]

The association of bupivacaine and fentanyl appeared as the best method of inducing satisfactory obstetrical analgesia. But the various techniques of drug administration had to be detailed; this justified the present work, a single-blind controlled trial performed on 159 primipara women at term (except one of them), randomized in four groups, after informed consent. In each group, the number of patients, the age and the degree of uterine dilatation at the beginning of the epidural anaesthesia were comparable. Epidural anaesthesia aimed to improve the maternal comfort during labour. After a first epidural injection of 10 ml, several other injections of 6 ml were carried out according to four different protocols (I, II, III, IV), with different concentrations of fentanyl (respectively 0, 0.05, 0.1 and 0.15 mg). The mean total dosages of fentanyl were statistically higher in the protocols III and IV. The foetal cardiac rhythm and uterine contractions were monitored continuously as well as maternal blood pressure and heart beats during labour. The following parameters were assessed: contraction pain intensity (five point scale), the onset of analgesia, the duration of analgesia, the length of labour, the interval between the first drug injection and subsequent injections, the type of delivery. In the newborn, Apgar score was assessed at 1, 5 and 10 min after delivery. The degree of analgesia was statistically improved in the groups receiving fentanyl, without any differences between them. On the other hand, the length of labour was shorter with protocol II (lowest concentration of fentanyl).(ABSTRACT TRUNCATED AT 250 WORDS)