Effects of intrathecal opioids on cesarean section: a systematic review and Bayesian network meta-analysis of randomized controlled trials

PURPOSE

We aimed to compare the beneficial and harmful effects of opioids used as adjuncts to local anesthetics in patients undergoing cesarean section under spinal anesthesia.

METHODS

We searched electronic databases and ClinicalTrials.gov from their inception until March, 2021 without language restrictions. The primary outcome was the complete analgesia duration (Time to VAS > 0). Data were synthesized using the Bayesian random-effects model. Evidence confidence was evaluated using the Confidence In Network Meta-Analysis.

RESULTS

We identified 66 placebo-controlled randomized controlled trials (RCTs) comprising 4400 patients undergoing elective cesarean section. Compared with the placebo, intrathecal opioids (fentanyl, sufentanil, and morphine) significantly prolonged the analgesia duration by 96, 96, and 190 min, respectively (mean difference). Despite morphine ranking first, opioid efficacy was similar; the results were inconsistent with respect to other analgesic outcomes. Except for diamorphine, all opioids were associated with significant increases in the pruritus incidence. Sufentanil and morphine were associated with increases in the respiratory depression incidence.

CONCLUSIONS

We confirmed that intrathecal opioids benefit postoperative analgesia. Although morphine seems to be the most appropriate agent, some results were inconsistent, and the evidence confidence was often moderate or low, especially for adverse outcomes. Well-designed RCTs with an evidence-based approach are imperative for determining the most appropriate opioid for cesarean sections.

Strategies of analgesic treatment after cesarean delivery. Current state and new alternatives

The number of caesarean sections performed worldwide is increasing, and with it, the need for the optimal analgesia strategies. Deficient postoperative analgesia increases the need for opioids, delays recovery, and is associated with chronic pain and postpartum depression. It is essential to find good postoperative pain control strategies that facilitate early mobility, early recovery, and early hospital discharge with minimal side effects on the mother and infant. Multimodal analgesia based on neuroaxial anaesthesia with morphine in combination with non-opioids such as non-steroidal anti-inflammatory drugs and paracetamol, gives the best post-caesarean analgesia outcome, and allows anaesthesiologists to reserve opioids, corticoids, gabapentin, magnesium or ketamine for situations where neuroaxial anaesthesia cannot be performed, for high-risk patients, or when pain is difficult to control. Peripheral nerve block techniques can also be added, such as transverse abdominis plane block, erector spinae block, or continuous wound infiltration.

A Comparative Study of Analgesic Efficacy of Intrathecal Buprenorphine with Ultrasound-Guided Transversus Abdominis Plane Block for Postcesarean Delivery Analgesia

BACKGROUND

Women undergoing cesarean (CS) delivery present a unique set of challenges to the anesthetist in terms of postoperative pain management. This study was conducted to compare the analgesic efficacy of intrathecal buprenorphine (ITB) with ultrasound-guided transversus abdominis plane (TAP) block in post-CS delivery pain.

METHODOLOGY

A prospective randomized comparative study of sixty American Society of Anesthesiologists physical status I and II pregnant patients divided into two groups of thirty each as ITB group and TAP block group after satisfying the inclusion criteria.

RESULTS

In the present study, demographic data were comparable between both groups. The time to first analgesic request was significantly longer in ITB group (389.67 ± 90.78 min) compared to TAP group (669.17 ± 140.65 min) and was statistically significant, P < 0.001. The mean paracetamol consumption in the first 24 h was higher in the TAP group (3.5 g) compared to the ITB group (1.13 g) and was statistically significant, P < 0.0001, and the mean tramadol consumed in first 24 h was higher in the TAP (46.66 mg) group as compared to the ITB group (16.66 mg) and was statistically significant, P < 0.001. The mean visual analog scale scores assessed at 4, 6, 12, and 24 h was higher in the TAP group and was statistically significant, P < 0.001.

CONCLUSIONS

Our study showed that patients receiving ITB for post-CS pain management reported longer duration of analgesia, lower pain scores, and lower analgesic consumption during the first 24 h. The benefits of neuraxial opiates are significant and far outweigh the side effects.

Applying realistic medicine to intrathecal opioid utilisation in Scotland: do we have a standardised approach?

Intrathecal opioids (ITOs) are commonly administered as part of a multimodal anaesthetic strategy for a variety of surgical procedures. The evolution of laparoscopic surgical techniques has seen the popularity of ITOs increase as they are effective, well tolerated and lack the cardiovascular side effects associated with epidural infusions. The risk of delayed respiratory depression remains a concern; therefore, high-quality post-operative monitoring is vital. The evidence regarding the practicalities of ITO administration such as opioid dose, type, side effect prevalence and ideal post-operative care arrangements are sparse. As such, a variety of clinical opinion has been generated. In order to quantify this variation within Scotland, we devised a short telephone questionnaire regarding ITO utilisation. We contacted 16 acute surgical sites. Of these, 14 confirmed regular utilisation of ITOs. Our survey demonstrated significant variability in practice. Both diamorphine and morphine are utilised, but no centre could provide a reason to justify the choice of one over the other. The commonly administered dose range for both agents ranged between 100 and 1100 µg. Most centres employed post-operative monitoring geared towards the detection of delayed respiratory depression but this was not unanimous. Each centre had a variation on what observations nursing staff were expected to complete in the post-operative period. Itch and nausea were not encountered frequently. Two centres experienced at least one episode of delayed respiratory depression which was detected and treated with no patient harm. In the report to the Scottish Government, 'Realistic Medicine', by the Chief Medical Officer, the need to reduce unnecessary variation in practice and outcomes is highlighted. We believe that a national sprint audit would gather sufficient prospective data to further determine whether a correlation exists between side effect profile and ITO utilisation practice. We hope this would help form a consensus and guide a standardised approach.

Optimal Pain Management After Cesarean Delivery

Cesarean delivery rates are increasing worldwide, and effective postoperative pain management is a key priority of women undergoing cesarean delivery. Inadequate pain management in the acute postoperative period is associated with persistent pain, greater opioid use, delayed functional recovery, and increased postpartum depression. In addition to pain relief, optimal management of patients after cesarean delivery should address the goals of unrestricted maternal mobility, minimal maternal and neonatal side effects, rapid recovery to baseline functionality, and early discharge home. Multimodal analgesia should include neuraxial morphine in conjunction with nonopioid adjuncts, with additional oral or intravenous opioids reserved for severe breakthrough pain.

Intrathecal morphine for postoperative analgesia: Current trends

The practice of anesthesiology has always been governed by evidence-based medicine. The quick turnover rate of patients in the operating room and patient safety and satisfaction, have also further changed the way we practice anesthesia. The use of intrathecal (IT) opiates as an effective form of postoperative pain relief has been established for many years. Morphine was the first opioid used by IT route. In clinical practice, morphine is regarded as the gold standard, or benchmark, of analgesics used to relieve intense pain. Perhaps for this reason, IT morphine has been used for over 100 years for pain relief. IT morphine is one of the easiest, cost-effective and reliable techniques for postoperative analgesia and technical failures are rare. And yet there is no consensus amongst anesthesiologists regarding the dose of IT morphine. Like all other methods of pain relief, IT morphine also has some side effects and some of them are serious though not very common. This review article looks into some of the key aspects of the use of IT morphine for post-operative analgesia and various doses for different procedures are discussed. This article also describes the side effects of IT morphine and how to treat and prevent them.

The use of spinal opioids in cancer pain

Approximately two-thirds of cancer patients suffer from significant pain. Until recently, less expensive and less costly conservative treatments have been utilized to treat these patients' pain, but the outcomes have been poor, with many experiencing inadequate pain relief. Although intraspinal opioid therapy is relatively new and more invasive than traditional treatments, it can provide most cancer patients better pain relief with less side effects. Intraspinal opioids can be used successfully to treat intractable malignant pain states.