A comparison of bupivacaine-fentanyl-morphine with bupivacaine-fentanyl-diamorphine for caesarean section under spinal anaesthesia

Evidence-based guidance for use of intrathecal morphine as an alternative to diamorphine for Caesarean delivery analgesia

Intrathecal morphine in combination with fentanyl is an effective and safe alternative to diamorphine for Caesarean delivery analgesia. Evidence suggests minimal differences in clinical efficacy and side-effects between intrathecal morphine and diamorphine. Recommended intrathecal morphine doses for Caesarean delivery analgesia are 100-150 ug.

Spinal-Induced Hypotension in Preeclamptic and Healthy Parturients Undergoing Cesarean Section

BACKGROUND

There is a widespread belief that spinal anaesthesia in patients with preeclampsia might cause severe hypotension and decreased uteroplacental perfusion. This study aimed to evaluate the incidence and severity of spinal induced-hypotension in preeclamptics and healthy parturients.

METHODS

Total of 78 patients (40 healthy and 38 preeclamptic) undergoing a C-Section with spinal anaesthesia were included. Spinal anaesthesia was performed with a mixture of 8-9 mg isobaric 0.5% bupivacaine, 20 mcg fentanyl and 100 mcg morphine (total volume 2.2-2.4 ml). Blood pressures (BP)-SBP, DBP, MAP were recorded non-invasively before performing spinal anaesthesia and at 2.5 minutes after a spinal puncture.

RESULTS

The BP falls (%) from baseline were significantly greater in the healthy parturients compared to those with preeclampsia (25.8% ± 10.1 vs 18.8% ± 17.0 for SBP, 28.5% ± 8.8 vs 22.5% ± 10.4 for DBP, and 31.2% ± 14.2 vs 18.2% ± 12.6% for MAP, p < 0.05). The incidence rate of hypotension in the preeclamptics was 25% compared to 53% in healthy parturients (p < 0.001). Higher doses of vasopressors both ephedrine (16.5 ± 8.6 vs 6.0 ± 2.0 mg) and phenylephrine (105 ± 25 mg) in the healthy women were required. There was no need for phenylephrine treatment in the preeclamptic group.

CONCLUSION

This study showed that the incidence and severity of spinal-induced hypotension in preeclamptic patients are less than in healthy women. The use of low dose spinal anaesthesia also contributed to this statement.

Risks of Regional Anaesthesia for Caesarean Section: Women's Recall and Information Sources

Recall and information sources regarding the risks of regional anaesthesia in women having lower segment caesarean section have not been adequately assessed previously. We aimed to survey women's recall of their pre-anaesthesia risk discussion and determine where women, presenting for lower segment caesarean section under regional anaesthesia, obtain risk information. Following a small pilot survey, women's responses were recorded for “spontaneous” or “prompted” recalled risks, the information source and its reliability. One-hundred and fifty women were surveyed following caesarean section. Seventy women (46.7%) had an elective procedure and 80 (53.3%) had an emergency procedure. Overall, 142 women (94.6%) recalled at least four risks (44.6% spontaneously; 66% prompted). Of those women giving at least four spontaneous responses, 41 (58.6%) had elective and 26 (32.5%) had emergency lower segment caesarean section (P=0.001). The majority of women stated that anaesthetists were the main, and most reliable, source of their information regarding risks of regional anaesthesia for caesarean section. This report identifies the risks associated with regional anaesthesia for caesarean section that women most frequently recall, namely headache, paralysis, nerve damage and inadequate block.

Comparison of the Efficacy and Safety of Morphine and Fentanyl as Adjuvants to Bupivacaine in Providing Operative Anesthesia and Postoperative Analgesia in Subumblical Surgeries Using Combined Spinal Epidural Technique

Introduction:

The combined spinal epidural (CSE) technique involves intentional subarachnoid blockade and epidural catheter placement during the same procedure to combine their individual best features, to reduce the total drug dosage and avoid their respective disadvantages. The addition of opioids to local anesthetics (bupivacaine) for CSE anesthesia (CSEA) is increasingly common to enhance the block. Neuraxial fentanyl is more potent and has shorter duration of action than morphine which provides prolonged anesthesia and analgesia, however at the cost of increased incidence of adverse effects like delayed respiratory depression.

Aims and Objectives:

The aim is to compare the efficacy and safety of morphine and fentanyl as adjuvants to bupivacaine in subumblical surgeries using CSE technique. The characteristics of sensory and motor block, intergroup variations in pain, cardiorespiratory parameters, and adverse effects were compared between the two groups.

Materials and Methods:

A total of 60 patients belonging to physical status American Society of Anesthesiologists Classes I and II, aged 18–60 years were randomized into two groups: Group A (n = 30) received intrathecal 0.5% heavy bupivacaine 12.5 mg and morphine 2.85 μg/kg; Epidural Anesthetic bolus (when required/T11Regression) 8 ml 0.25% isobaric bupivacaine and 0.04 mg/kg morphine; Epidural Analgesic bolus (postoperative visual analog scale [VAS] score >30) 5 ml 0.125% isobaric bupivacaine and 0.04 mg/kg morphine and Group B (n = 30) received intrathecal 0.5% heavy bupivacaine 12.5 mg and fentanyl 0.35 μg/kg; Epidural Anesthetic bolus (when required/T11Regression) 8 ml 0.25% isobaric bupivacaine and 0.7 μg/kg fentanyl; Epidural Analgesic bolus (postoperative VAS score >30) 5 ml 0.125% isobaric bupivacaine and 0.7 μg/kg fentanyl.

Results and Conclusion:

Group A had significantly prolonged two segment regression time, T11 regression time, lower mean VAS score, prolonged effective analgesia, and required lesser number of epidural boluses in 24 h as compared to Group B (P < 0.001). There were no significant differences between the groups considering onset of sensory block, duration of motor block, median maximum sensory block level achieved after spinal component (T6), median highest sensory block level achieved after epidural anesthetic bolus (T7-4seg enhancement after regression to T11), cardiorespiratory parameters and adverse effects. None of the patients had respiratory depression nor was there any failure of spinal/epidural component of CSEA. Thus, addition of morphine to bupivacaine in CSEA produced prolonged effective anesthesia and postoperative analgesia compared to addition of fentanyl to bupivacaine without producing undue adverse effects.

Perioperative analgesia after intrathecal fentanyl and morphine or morphine alone for cesarean section: A randomized controlled study

OBJECTIVES

Intrathecal morphine is used in the postoperative management of pain after caesarean section (CS), but might not be optimal for intraoperative analgesia. We hypothesized that intrathecal fentanyl could supplement intraoperative analgesia when added to a local anesthetic and morphine without affecting management of postoperative pain.

METHODS

This prospective, randomized, double-blind, parallel-group study included 60 parturients scheduled for elective CS. Spinal anesthesia consisted of bupivacaine with either morphine 100 μg (M group), or fentanyl 25 μg and morphine 100 μg (FM group). The frequency of intraoperative pain and pethidine consumption in the 24 hours postoperatively was recorded.

RESULTS

Fewer patients in the FM group required additional intraoperative analgesia (P < .01, relative risk 0.06, 95% confidence interval [CI] 0.004-1.04). The FM group was noninferior to the M group for 24-hour opioid consumption (95% CI -10.0 mg to 45.7 mg, which was below the prespecified boundary of 50 mg). Pethidine consumption in postoperative hours 1 to 12 was significantly higher in the FM group (P = .02). Postoperative nausea and vomiting (PONV) were more common in the FM group (P = .01). Visual analog scale scores, effective analgesia, Apgar scores, and rates of pruritus and respiratory depression were similar between the groups.

CONCLUSIONS

Intrathecal combination of fentanyl and morphine may provide better perioperative analgesia than morphine alone in CS and could be useful when the time from anesthesia to skin incision is short. However, an increase in PONV and possible acute spinal opioid tolerance after addition of intrathecal fentanyl warrants further investigation using lower doses of fentanyl.

A randomized clinical study comparing spinal anesthesia with isobaric levobupivacaine with fentanyl and hyperbaric bupivacaine with fentanyl in elective cesarean sections

BACKGROUND

To date, racemic bupivacaine is the most popular local anesthetic for spinal anesthesia in parturients undergoing elective cesarean delivery. With the introduction of levobupivacaine as pure S (-) enantiomer of bupivacaine which offers advantages of lower cardiotoxicity and neurotoxicity and shorter motor block duration, its use has widely increased in India. However, very few studies have been conducted about its efficacy in obstetric anesthesia. Thus, this study was undertaken to compare the sensorial, motor block levels, and side-effects of equal doses of hyperbaric bupivacaine and levobupivacaine with intrathecal fentanyl addition in elective cesarean cases.

MATERIALS AND METHODS

After approval of College Ethical Committee, 30 parturient with American Society of Anesthesiologists I-II undergoing elective cesarean section were enrolled for study with their informed consent. They were randomly divided equally to either Group BF receiving 10 mg (2 ml) hyperbaric bupivacaine and 25 mcg (0.5 ml) fentanyl, or Group LF receiving 10 mg (2 ml) isobaric levobupivacaine and 25 mcg (0.5 ml) fentanyl. Sensory and motor block characteristics of the groups were assessed with pinprick, cold swab, and Bromage scale; observed hemodynamic changes and side-effects were recorded. Effects on the neonate were observed by APGAR score at 1 and 5 min and umbilical cord blood gas analysis.

RESULTS

Hemodynamic parameters like mean arterial pressure of Group BF were found to be lower. Group BF exhibited maximum motor block level whereas in Group LF, max sensorial block level and postoperative visual analog scale scores were higher. Umbilical blood gas pCO2 was slightly higher, and pO2 was marginally lower in Group BF. Onset of motor block time, time to max motor block, time to T10 sensorial block, reversal of two dermatome, the first analgesic need were similar in both groups.

CONCLUSION

Intrathecal isobaric levobupivacaine-fentanyl combination is a good alternative to hyperbaric bupivacaine-fentanyl combination in cesarean surgery as it is less effective in motor block, it maintains hemodynamic stability at higher sensorial block levels.

Emergency Caesarean section: best practice*

Good multidisciplinary communication is crucial to the safe management of women requiring non-elective Caesarean section. Anaesthetists should participate actively in resuscitation of the fetus in utero; relief of aortocaval compression is paramount. Epidural top-up with levobupivacaine 0.5% is the anaesthetic of choice for women who have been receiving labour epidural analgesia. If epidural top-up fails to provide bilateral light touch anaesthesia from S5 - T5, a combined spinal-epidural technique with small intrathecal dose of local anaesthetic is a useful approach. Pre-eclampsia is not a contra-indication to single-shot spinal anaesthesia, which is the technique of choice for most women presenting for Caesarean section without an epidural catheter in situ. Induction and maintenance doses of drugs for general anaesthesia should not be reduced in the belief that the baby will be harmed. Early postoperative observations are geared towards the detection of overt or covert haemorrhage.

Opioid-related side-effects after intrathecal morphine: a prospective, randomized, double-blind dose-response study

BACKGROUND AND OBJECTIVE

The aim of this prospective, randomized, double-blind investigation was to assess the dose-effect characteristics of postoperative nausea and vomiting after intrathecal administration of small doses of morphine (from 0.015 to 0.25 mg) in opioid-naïve, non-surgical patients.

METHODS

With Ethic Committee approval and written informed consent 144 opioid-naïve patients suffering from non-cancerous chronic back-pain, and receiving intrathecal morphine as diagnostic test for their chronic pain, were randomly allocated to receive intrathecal injection of 0.015 mg (Group I, n=25), 0.03 mg (Group II, n=30), 0.06 mg (Group III, n=31) or 0.25 mg (Group IV, n=33) morphine. The control group consisted in 25 further patients not included in the dose-effect study and receiving a placebo injection of normal saline in the interspinous ligament. A blinded observer recorded the occurrence of pruritus, nausea, vomiting, urinary retention and respiratory depression (respiratory rate<6 bpm) at 2, 4 and 24 h after injection.

RESULTS

Clinically significant pain relief was observed in all patients receiving intrathecal morphine but only six patients (25%) of the control group (P=0.0005). The incidence of pruritus was lower in patients of Groups III (6%) and IV (3%) than in Groups I (12%) and II (20%) (P=0.002). The incidence of nausea and vomiting was higher at 2- and 4-h observation times, and decreased 24 h after intrathecal injection. Surprisingly, nausea was more frequent in Groups I (56%) and II (50%) than in Groups III (33%) and IV (24%) (P=0.0005). Vomiting was higher in patients receiving morphine than in control group, but without differences among the four doses. No urinary retention was observed in the control group, while 2 h after intrathecal injection urinary retention was observed in 20-40% of cases, and decreased to less than 10% 24 h after spinal injection without differences among the four doses.

CONCLUSIONS

The onset and incidence of minor opioid-related side-effects after intrathecal morphine administration do not depend on its dose, occurring with even very small doses of morphine. Accordingly, they can be considered as a patient-dependent effect of the drug, suggesting the presence of a primary dose-independent excitatory component that might be related to the theory of the bimodal activation of opioid receptors. The very low incidence major respiratory depression prevents us from drawing any conclusion about the dose-effect relationship for this side-effect, and further properly powered studies should be advocated to evaluate major respiratory depression after spinal morphine.

A comparison of intrathecal fentanyl and diamorphine as adjuncts in spinal anaesthesia for Caesarean section

This randomised controlled trial examines the effects of fentanyl and diamorphine, alone and in combination, as adjuncts to spinal anaesthesia for Caesarean section. Ninety-nine women undergoing elective Caesarean section with spinal anaesthesia using 0.5% hyperbaric bupivacaine were randomly allocated to receive fentanyl 15 microg (F), diamorphine 0.25 mg (D), or fentanyl 15 microg plus diamorphine 0.25 mg (FD), intrathecally. All women received morphine via a patient controlled analgesia system after surgery. There was no significant difference between the groups in time to achieve a block, discomfort, ephedrine use, nausea and vomiting, pruritus and sedation during surgery. Significant differences were observed in morphine consumption 4, 8, 12 and 24 h after surgery between both F and D groups, and F and FD groups, and also at 2 h between F and FD groups. There was a significant difference in pruritus at 4 h between the F and FD group. Our results suggest that diamorphine alone provides optimum benefits during and after surgery, when used in combination with hyperbaric bupivacaine for Caesarean section.