Efficacy of intrathecal morphine with epidural ropivacaine infusion for postcesarean analgesia

Non-pulmonary complications of intrathecal morphine administration: a systematic review and meta-analysis with meta-regression

BACKGROUND

Intrathecal morphine provides effective analgesia for a range of operations. However, widespread implementation into clinical practice is hampered by concerns for potential side-effects. We undertook a systematic review, meta-analysis, and meta-regression with the primary objective of determining whether a threshold dose for non-pulmonary complications could be defined and whether an association could be established between dose and complication rates when intrathecal morphine is administered for perioperative or obstetric analgesia.

METHODS

We systematically searched the literature for randomised controlled trials comparing intrathecal morphine vs control in patients undergoing any type of surgery under general or spinal anaesthesia, or women in labour. Primary outcomes were rates of postoperative nausea and vomiting, pruritus, and urinary retention within the first 24 postoperative hours, analysed according to doses (1-100 μg; 101-200 μg; 201-500 μg; >500 μg), type of surgery, and anaesthetic strategy. Trials were excluded if doses were not specified.

RESULTS

Our analysis included 168 trials with 9917 patients. The rates of postoperative nausea and vomiting, pruritus, and urinary retention were significantly increased in the intrathecal morphine group, with an odds ratio (95% confidence interval) of 1.52 (1.29-1.79), P<0.0001; 6.11 (5.25-7.10), P<0.0001; and 1.73 (1.17-2.56), P=0.005, respectively. Meta-regression could not establish an association between dose and rates of non-pulmonary complications. There was no subgroup difference according to surgery for any outcome. The quality of evidence was low (Grading of Recommendations Assessment, Development, and Evaluation [GRADE] system).

CONCLUSIONS

Intrathecal morphine significantly increased postoperative nausea and vomiting, pruritus, and urinary retention after surgery or labour in a dose-independent manner.

SYSTEMATIC REVIEW PROTOCOL

PROSPERO (CRD42023387838).

Comparison of the Efficacies of Three Different Intrathecal Doses of Morphine in Achieving Postcesarean Delivery Analgesia

PURPOSE

The objective of this study is to compare the efficacies of 3 different intrathecal doses (80, 120, and 160 mcg) of morphine in achieving postcesarean delivery analgesia and the severity of the side effects thereof.

DESIGN

A prospective, randomized, double-blind study.

METHODS

A total of 150 pregnant women between the ages of 18 and 40, with a gestational week >36, who were planned to have elective cesarean section were included in the study. Patients were randomized into 3 groups based on the dosages of intrathecal doses of morphine (80, 120, and 160 mcg) they will receive in addition to 10 mg 0.5% hyperbaric bupivacaine and 20 mcg fentanyl. Intravenous (IV) patient-controlled analgesia (PCA) prepared with fentanyl was administered to each patient after the surgery. Postoperative 24-hour total IV PCA-fentanyl consumption was recorded. The patients were evaluated for side effects such as pain, nausea-vomiting, pruritus, sedation score, and respiratory depression after the surgery.

FINDINGS

PCA-fentanyl consumption was significantly higher in Group 1 compared to Group 2 and 3 (P = .047). There was no significant differences between the groups in terms of nausea-vomiting scores. The pruritus scores were significantly higher in Group 3 compared to Group 1 (P = .020). The pruritus scores were significantly higher in all groups at the postoperative 8th-hour (P = .013). Respiratory depression, which would require treatment, was not observed in any patient.

CONCLUSIONS

Based on the study findings, it was concluded that 120 mcg intrathecal morphine provides adequate analgesia with minimal side effects in cesarean sections.

Zero Patient-controlled Analgesia is an Achievable Target for Postoperative Rapid Recovery Management of Adolescent Idiopathic Scoliosis Patients

STUDY DESIGN

Retrospective review.

OBJECTIVE

The objective of this study was to report on one institution's use of single bolus micro-dose intrathecal morphine as part of a rapid recovery pathway during posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) and its comparison to patients whose pain was controlled with patient-controlled analgesia (PCA).

SUMMARY OF BACKGROUND DATA

Narcotic substance addiction has risen across all patient populations, including pediatrics. Narcotics have been historically used in complex spine surgeries as a measure of pain control, predominantly provided as PCA and additional take-home medication.

METHODS

AIS patients undergoing PSF from 2015 to 2019 were reviewed. In 2018, we instituted a standardized rapid recovery pathway for scoliosis patients undergoing PSF utilizing micro-dose intrathecal morphine (ITM-RRP). Before this, traditional protocol with PCA was used for postoperative management. Perioperative data, morphine consumption and prescription refill requests were compared.

RESULTS

There were 373 AIS patients total in this study, of which 250 patients were in the PCA group and 123 in the ITM-RRP Group. Preoperative Cobb angles (P = 0.195), as well as levels fused (P = 0.481) and body mass index (P = 0.075) were similar. 69.4% of ITM-RRP patients had a length of stay ≤3 days, significantly >11.6% of PCA patients (P < 0.001). ITM-RRP patients began ambulating significantly earlier with 84.6% patients out of bed by postoperative day 1 versus 8% PCA patients (P < 0.001). Additionally, ITM-RRP patients had significantly lower VAS pain scores with activity and earlier initial bowel movements (P < 0.001).Postoperative emesis was similar (P = 0.11). No patients had pruritus, respiratory depression, or required supplemental oxygenation.

CONCLUSION

This is the first study to show that a rapid recovery protocol utilizing single micro-dose ITM with oral analgesics have adequate recovery, significantly better postoperative pain control and superior perioperative outcomes to traditional protocols using PCA in the AIS population following PSF.Level of Evidence: 3.

Effects of different epidural initiation volumes on postoperative analgesia in cesarean section

Background/aim

The aim of this study was to compare the effects of different epidural initiation volumes on postoperative pain scores, analgesic requirements, and side effects in pregnant women administered patient-controlled epidural analgesia (PCEA) for postoperative pain after cesarean sections.

Materials and methods

Eighty-one pregnant women, aged 18–45 years, were included in this randomized, double-blind study. Combined spinal epidural anesthesia was administered for each cesarean section. The patients were divided into 3 groups and different volumes (20 mL, 10 mL, and 5 mL) of the study drug (0.0625% bupivacaine plus 2 μg/mL of fentanyl) were administered 90 min after the spinal block via epidural catheter. The visual analogue scale (VAS) scores at rest and during movement, first PCEA dose time, number of PCEA doses required per hour, total analgesic consumed, and side effects were recorded postoperatively.

Results

There were no statistically significant differences among the groups in terms of the VAS rest and VAS movement scores. The times to the first analgesic dose requirement were longer in Group 10 and Group 20 than in Group 5. The analgesic requirement during the first 2 h was lower in Group 20 than in the other groups.

Conclusions

The PCEA initiations with different volumes provided similar pain scores. However, the 20 mL volume resulted in a lower analgesic dose requirement during the early postoperative period, and it also delayed the requirement for analgesia.

Comparison of intrathecal morphine with continuous patient-controlled epidural anesthesia versus intrathecal morphine alone for post-cesarean section analgesia: a randomized controlled trial

Background

Several neuraxial techniques have demonstrated effective post-cesarean section analgesia. According to previous reports, it is likely that patient-controlled epidural analgesia (PCEA) without opioids is inferior to intrathecal morphine (IM) alone for post-cesarean section analgesia. However, little is known whether adding PCEA to IM is effective or not. The aim of this study was to compare post-cesarean section analgesia between IM with PCEA and IM alone.

Methods

Fifty patients undergoing elective cesarean section were enrolled in this prospective randomized study. Patients were randomized to one of two groups: IM group and IM + PCEA group. All patients received spinal anesthesia with 12 mg of 0.5% hyperbaric bupivacaine, 10 μg of fentanyl, and 150 μg of morphine. Patients in IM + PCEA group received epidural catheterization through Th11–12 or Th12-L1 before spinal anesthesia and PCEA (basal 0.167% levobupivacaine infusion rate of 6 mL/h, bolus dose of 3 mL in lockout interval of 30 min) was commenced at the end of surgery. A numerical rating scale (NRS) at rest and on movement at 4,8,12,24,48 h after the intrathecal administration of morphine were recorded. In addition, we recorded the incidence of delayed ambulation and the number of patients who requested rescue analgesics. We examined NRS using Bonferroni’s multiple comparison test following repeated measures analysis of variance; p < 0.05 was considered as statistically significant.

Results

Twenty-three patients in each group were finally analyzed. Mean NRS at rest was significantly higher in IM group than in IM + PCEA group at 4 (2.7 vs 0.6), 8 (2.2 vs 0.6), and 12 h (2.5 vs 0.7), and NRS during mobilization was significantly higher in IM group than in IM + PCEA group at 4 (4.9 vs 1.5), 8 (4.8 vs 1.9), 12 (4.9 vs 2), and 24 h (5.7 vs 3.5). The number of patients who required rescue analgesics during the first 24 h was significantly higher in IM group compared to IM + PCEA group. No significant difference was observed between the groups in incidence of delayed ambulation.

Conclusions

The combined use of PCEA with IM provided better post-cesarean section analgesia compared to IM alone.

Trial registration

UMIN-CTR (Registration No. UMIN000032475). Registered 6 May 2018 – Retrospectively registered.

A review of opioid-induced itching after cesarean birth

Currently, about one-third of all women giving birth have a cesarean surgical birth, and the majority are given an epidural or spinal anesthetic containing an opioid for surgery. An unpleasant side effect experienced by many of these women is itching. This article reviews the literature on itching after spinal and epidural administration of opioids and how nurses can best manage this side effect.

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.

Patient-controlled epidural levobupivacaine with or without fentanyl for post-cesarean section pain relief

PURPOSE

The purpose of this study was to compare the analgesic properties of levobupivacaine with or without fentanyl for patient-controlled epidural analgesia after Cesarean section in a randomized, double-blinded study.

METHODS

We enrolled American Society of Anesthesiologists class I/II, full-term pregnant women at National Taiwan University Hospital who received patient-controlled epidural analgesia after Cesarean section between 2009 and 2010. Eighty women were randomly assigned into two groups. In group A, the 40 subjects received drug solutions made of 0.6 mg/ml levobupivacaine plus 2 mcg/ml fentanyl, and in group B the 40 subjects received 1 mg/ml levobupivacaine. Maintenance was self-administered boluses and a continuous background infusion.

RESULTS

There were no significant differences in the resting and dynamic pain scales and total volume of drug used between the two groups. Patient satisfaction was good in both groups.

CONCLUSION

Our study showed that pure epidural levobupivacaine can provide comparative analgesic properties to the levobupivacaine-fentanyl combination after Cesarean section. Pure levobupivacaine may serve as an alternative pain control regimen to avoid opioid-related adverse events in parturients.

Prophylaxis and treatment of the side-effects of neuraxial morphine analgesia following cesarean delivery

PURPOSE OF REVIEW

Neuraxial morphine is commonly used for analgesia after cesarean delivery, but is frequently associated with postoperative nausea and vomiting (PONV) and pruritus. This review describes the recent advances in the management of those side-effects.

RECENT FINDINGS

Neuraxial-morphine-induced side-effects are dose related; therefore, the minimum effective dose should be used. Dexamethasone, 5HT3 receptor antagonists, antihistamines, and anticholinergics reduce the incidence of PONV, whereas metoclopramide 10 mg does not appear to be effective for PONV prophylaxis in this patient population. Combination antiemetic therapy provides improved prophylaxis compared with monotherapy, but has seldom been studied in women undergoing cesarean delivery with neuraxial morphine. Studies of P6 acupressure reported inconsistent results. Polymorphism of the μ-opioid receptor may affect the severity of neuraxial-morphine-induced pruritus. Opioid antagonists and mixed agonist/antagonists appear to be the most useful for the management of opioid-induced pruritus. Prophylactic 5HT3 receptor antagonists and dexamethasone do not seem to be effective for reducing the incidence of pruritus. In contrast, ondansetron, pentazocine, and dimenhydrinate may be useful for treating established pruritus.

SUMMARY

PONV and pruritus are frequent side-effects of neuraxial morphine. Future studies investigating combination antiemetic therapy, long-acting antiemetics, and strategies to manage pruritus are needed.

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.

Role of spinal neurotransmitter receptors in itch: new insights into therapies and drug development

Targets for antipruritic therapies are now expanding from the skin to the central nervous system. Recent studies demonstrate that various neuronal receptors in the spinal cord are involved in pruritus. The spinal opioid receptor is one of the best-known examples. Spinal administration of morphine is frequently accompanied by segmental pruritus. In addition to μ-opioid receptor antagonists, κ-opioid receptor agonists have recently come into usage as novel antipruritic drugs, and are expected to suppress certain subtypes of itch such as hemodialysis- and cholestasis-associated itch that are difficult to treat with antihistamines. The gastrin-releasing peptide receptor in the superficial dorsal horn of the spinal cord has also received recent attention as a novel pathway of itch-selective neural transmission. The NMDA glutamate receptor appears to be another potential target for the treatment of itch, especially in terms of central sensitization. The development of NMDA receptor antagonists with less undesirable side effects on the central nervous system might be beneficial for antipruritic therapies. Drugs suppressing presynaptic glutamate-release such as gabapentin and pregabalin also reportedly inhibit certain subtypes of itch such as brachioradial pruritus. Spinal receptors of other neuromediators such as bradykinin, substance P, serotonin, and histamine may also be potential targets for antipruritic therapies, given that most of these molecules interfere not only with pain, but also with itch transmission or regulation. Thus, the identification of itch-specific receptors and understanding itch-related circuits in the spinal cord may be innovative strategies for the development of novel antipruritic drugs.

Anatomy and neurophysiology of pruritus

Itch has been described for many years as an unpleasant sensation that evokes the urgent desire to scratch. Studies of the neurobiology, neurophysiology, and cellular biology of itch have gradually been clarifying the mechanism of itch both peripherally and centrally. The discussion has been focused on which nerves and neuroreceptors play major roles in itch induction. The "intensity theory" hypothesizes that signal transduction on the same nerves leads to either pain (high intensity) or itch (low intensity), depending on the signal intensity. The "labeled-line coding theory" hypothesizes the complete separation of pain and itch pathways. Itch sensitization must also be considered in discussions of itch. This review highlights anatomical and functional properties of itch pathways and their relation to understanding itch perception and pruritic diseases.