Compared to basal infusion, Automated Mandatory Bolus May Improve Epidural Analgesia during Labor And Childbirth

Epidural analgesia is commonly used to provide pain relief during labour and childbirth. It involves the administration of local anaesthetics into the epidural space, resulting in a sensory blockade of the abdomen, pelvis, and perineum. To enhance analgesia, epidural opioids are often co-administered. Different methods of delivering epidural medications, such as basal infusion (BI) or automated mandatory bolus (AMB), have been employed, with patient-controlled epidural analgesia (PCEA) allowing patients to self-administer additional boluses of medication.

Determining the optimal technique for delivering epidural medications, which offers effective pain relief while minimising adverse effects, has been a subject of interest. However, previous reviews have not provided clear evidence regarding the superiority of one method over the other. Additionally, factors such as the initiation of epidural analgesia (e.g., combined spinal-epidural) and the types and doses of medications used have not been adequately considered.

The review article was published in Cochrane Database Of Systematic Reviews by Hon Sen Tan which included a total of 18 studies involving 4,590 women. Out of these, 13 studies focused on healthy nulliparous women, while five studies included both nulliparous and multiparous women. All participants had term pregnancies, and women with preterm or complicated pregnancies were excluded from the studies.The techniques used to initiate epidural analgesia varied among the studies.

Seven studies utilized combined spinal epidural, 10 used epidural, and one used dural puncture epidural (DPE). There was also variation in the types of analgesics used. Ropivacaine with fentanyl was employed in eight studies, ropivacaine with sufentanil in three studies, levobupivacaine with sufentanil in two studies, levobupivacaine with fentanyl in one study, and bupivacaine with fentanyl in four studies.

● The results of the review indicated that automated mandatory bolus (AMB) was associated with a lower incidence of breakthrough pain compared to basal infusion (BI). The risk ratio (RR) for breakthrough pain was 0.71 with a 95% confidence interval (CI) of 0.55 to 0.91.

● AMB was also linked to a reduction in the hourly consumption of local anaesthetics (LA) in bupivacaine equivalents, with a mean difference (MD) of -0.84 mg/h and a 95% CI of -1.29 to -0.38.

● The incidence of caesarean delivery and instrumental delivery did not show significant differences between AMB and BI. The RR for caesarean delivery was 0.85 with a 95% CI of 0.69 to 1.06, while the RR for instrumental delivery was 0.85 with a 95% CI of 0.71 to 1.01.

● There was no significant difference in the duration of labour analgesia, with an MD of -8.81 minutes and a 95% CI of -19.38 to 1.77.Regarding maternal satisfaction and Apgar scores, the data were not pooled due to differences in measurement methods and timing.

● The results reported narratively suggested that AMB may be associated with increased maternal satisfaction, as eight studies reported increased satisfaction and six reported no difference.

● All studies showed no difference in Apgar scores.Subgroup analyses did not reveal significant differences, except for the comparison of epidural alone versus combined spinal-epidural (CSE) techniques, which found significant differences in LA consumption between AMB and BI.

The authors concluded that AMB offers advantages over BI in terms of reducing breakthrough pain and lowering local anaesthetic consumption. It may also improve maternal satisfaction. However, further large-scale studies are needed to assess the impact of AMB on the incidence of caesarean and instrumental deliveries. Overall, these findings contribute valuable insights into optimizing epidural analgesia for labour and childbirth, aiming to enhance the birthing experience for women while ensuring effective pain relief and minimizing adverse effects.

Reference:

Tan, H. S., Zeng, Y., Qi, Y., Sultana, R., Tan, C. W., Sia, A. T., Sng, B. L., & Siddiqui, F. J. (2023). Automated mandatory bolus versus basal infusion for maintenance of epidural analgesia in labour. Cochrane Database of Systematic Reviews, 6, CD011344. https://doi.org/10.1002/14651858.CD011344.pub3