Postoperative intraspinal opioid analgesia after caesarean section; a randomised comparison of subarachnoid morphine and epidural pethidine

Randomized study of postcesarean analgesia with intrathecal morphine alone or combined with clonidine

STUDY OBJECTIVE

To investigate the efficacy of the combination of intrathecal morphine with clonidine in comparison with 2 doses of intrathecal morphine alone for postcesarean analgesia.

DESIGN

Prospective, double-blinded, randomized clinical trial.

SETTING

Maternity ward of Hospital Santa Cruz, Curitiba, Paraná, Brazil (operating room and ward).

PATIENTS

The study included 195 American Society of Anesthesiologist I to III singleton parturients undergoing elective cesarean section.

INTERVENTIONS

The patients were randomized into 3 groups (M50, M100, and M/C). Patients were anesthetized intrathecally with 12 mg of 0.5% hyperbaric bupivacaine and 50 μg or 100 μg morphine (groups M50 and M100, respectively) or 50 μg morphine and 75 μg clonidine (group M/C).

MEASUREMENTS

The patients were subsequently assessed for pain levels and side effects at 9 to 11 hours and 22 to 24 hours after the injection.

MAIN RESULTS

There was no difference in the quality of pain relief among the groups. In all 3 groups, pain was more intense during the first assessment. Pruritus and nausea were more frequent in group M100, and dizziness was more frequent in group M/C; however, these results were statistically insignificant. The group receiving clonidine showed a significantly lower incidence of shivering compared with the other groups.

CONCLUSIONS

At these doses, there was no benefit of associating clonidine with morphine to improve postcesarean analgesia. Considering that higher doses of morphine were associated with more side effects, 50 μg of intrathecal morphine alone seems to be a better option for analgesia. The use of clonidine to reduce postoperative shivering must be balanced against the potential risks of hypotension, bradycardia, dizziness, and sedation.

Comparative study between doses of intrathecal morphine for analgesia after caesarean

BACKGROUND AND OBJECTIVES

Analgesia after caesarean section is important because postpartum women with pain have difficulty in mobility, which undermines breastfeeding. Intrathecal morphine provides adequate and prolonged analgesia after cesarean. The aim of this study was to compare the quality of analgesia provided by two doses of intrathecal morphine and its side effects in patients undergoing cesarean section.

METHOD

The study included 123 pregnant women with gestational age over 38 weeks and scheduled for cesarean section. The women were randomly allocated into two groups to receive either 50 or 100 μg of intrathecal morphine (Group 50/Group 100). All patients were intrathecally anesthetized with 12 mg of 0.5% hyperbaric bupivacaine. Patients were assessed between the 9(th) and 11(th) hour and the 22(nd) and 24(th) hour after blockade for quality of analgesia, analgesic consumption, side effects, and main cause of discomfort in the first 24 hours after surgery.

RESULTS

There was similarity between groups regarding anthropometric data and obstetric history. There was no statistical difference in pain intensity between groups. In both groups, pain was more intense in the first 12 hours after anesthesia (p < 0.001). Tramadol hydrochloride consumption and time to first dose were similar in both groups. Pruritus was the most common side effect, with statistically higher incidence in Group 100 (p = 0.026).

CONCLUSIONS

Intrathecal morphine 50 μg provides the same quality of analgesia as 100 μg, with a lower incidence of side effects.

Analgesia after caesarean delivery

As the number of women giving birth by caesarean increases throughout most of the developed world, so too is research into postoperative pain relief for these women. Like most other post-surgical populations, the new mother needs effective pain relief so that she can mobilise early but she also has the added responsibility of needing to care for her newborn baby. There is no 'gold standard' for post-caesarean pain management; the number of options is large and the choice of method is at least partly determined by drug availability, regional and individual preferences, resource limitations and financial considerations. Most methods rely on opioids, supplemented with anti-inflammatory analgesics, nerve blocks or other adjunctive techniques. The aim of this review is to detail commonly used opioid-based methods and to review the evidence supporting non-opioid methods, when incorporated into a multimodal approach to post-caesarean pain management. Areas of promising research are also discussed.

Prevention of postoperative nausea and vomiting after intrathecal morphine for Cesarean section: a randomized comparison of dexamethasone, droperidol, and a combination

BACKGROUND

Intrathecal morphine provides good analgesia after cesarean delivery but the side effects include nausea and vomiting. Low-dose droperidol (0.625 mg) combined with dexamethasone 4 mg is postulated to have an additive antiemetic effect with less side effects. We therefore compared single doses of dexamethasone and droperidol alone with a low-dose combination of the two, to prevent spinal morphine-induced nausea and vomiting after cesarean section.

METHODS

In a double-blind study, 120 women undergoing elective cesarean section under spinal anesthesia (using 0.5% bupivacaine 10 mg and morphine 0.2 mg) were allocated randomly to receive dexamethasone 8 mg, droperidol 1.25 mg, dexamethasone 4 mg and droperidol 0.625 mg, or placebo, before the end of surgery. The incidences of nausea and vomiting, sedative score, pain score, and side effects were recorded.

RESULTS

The incidence of nausea and vomiting within 6 h postoperatively was lower and incidence of no nausea and vomiting for 24 h postoperatively was significantly higher for the combination group compared to the placebo group and the dexamethasone only group. Sedation scores within 3 h postoperatively and incidence of restlessness for the combination group were significantly lower than in the droperidol only group.

CONCLUSION

An additive antiemetic effect and no significant side effects were shown for the combination of dexamethasone 4 mg and droperidol 0.625 mg. This combination was more effective than either dexamethasone 8 mg or droperidol 1.25 mg alone in preventing nausea and vomiting after spinal anesthesia using 0.5% bupivacaine and morphine 0.2 mg.

Postcesarean analgesia with spinal morphine, clonidine, or their combination

In this randomized, double-blind trial in 240 women, we investigated the analgesic efficacy and duration of subarachnoid fentanyl 15 microg with morphine, clonidine, or both morphine and clonidine for cesarean delivery. A dose-finding analysis showed similar postoperative efficacy and side effects for groups receiving morphine 100 microg with clonidine 60, 90, or 150 microg. Data from these groups were combined (MC60-150, n = 113) and compared with groups receiving morphine 100 microg (n = 39), clonidine 150 microg (n = 39), or morphine 100 microg plus clonidine 30 microg (n = 41). The four groups differed in the time to patient-controlled morphine use and cumulative morphine consumption (P < 0.0001 and P < 0.001, respectively), with the longest duration and smallest dose in MC60-150. Pain scores were significantly different among groups. Onset of sensory block, ephedrine requirement and incidence of hypotension, patient satisfaction, and recovery were similar. Groups receiving clonidine had greater sedation, those receiving morphine had more severe pruritus, and group MC60-150 showed a trend to more vomiting intraoperatively. Compared with morphine 100 microg or clonidine 150 microg alone, the combination of subarachnoid morphine 100 microg and at least 60 microg of clonidine was found to increase the duration of postcesarean analgesia, reduce opioid requirement, and increase intraoperative sedation.

IMPLICATIONS

A multimodal approach to postcesarean analgesia, using subarachnoid bupivacaine, fentanyl, morphine 100 microg, and clonidine 60 microg, improves pain relief compared with morphine 100 microg or clonidine 150 microg alone, but increases intraoperative sedation and may increase perioperative vomiting.

The effect of intravenous ketorolac on opioid requirement and pain after cesarean delivery

Nonsteroidal antiinflammatory drugs, including ketorolac, are widely used for postoperative analgesia. This randomized, double-blinded trial compared IV ketorolac or saline combined with meperidine patient-controlled epidural analgesia (PCEA) after cesarean delivery. Fifty healthy parturients scheduled for elective cesarean delivery under combined spinal-epidural anesthesia received PCEA plus either IV ketorolac (Group K) or saline (Group C) for 24 h. The ketorolac dose was modified, after six patients had been studied, based on new product information recommending a maximum of 120 mg ketorolac over 24 h. Group K (n = 24) and Group C (n = 20) were demographically similar. During the first 24 h, Group K used significantly less meperidine (P < 0.05). Postoperative pain at rest and with movement, and patient satisfaction, did not differ significantly between groups, except that worst pain at 12 h was less in Group K (P < 0.005). The two groups were similar with respect to patient recovery and side effects. IV ketorolac, as an adjunct to PCEA after cesarean delivery, produced a meperidine dose-sparing effect of approximately 30%, but did not significantly improve pain relief, reduce opioid-related side effects, or change patient outcome.