The RESPITE trial: remifentanil intravenously administered patient-controlled analgesia (PCA) versus pethidine intramuscular injection for pain relief in labour: study protocol for a randomised controlled trial

Comparative effects of epidural analgesia and intramuscular morphine on maternal and neonatal outcomes: a retrospective cohort study

BACKGROUND

The global practice of pain management during labor involves the use of epidural analgesia or intramuscular morphine. However, the impact of these methods on maternal and neonatal short-term outcomes remains uncertain.

OBJECTIVE

This study aimed to evaluate the effect of labor exposure to epidural analgesia and intramuscular morphine on neonatal intensive care unit admission rates and other associated maternal and neonatal outcomes such as sepsis, respiratory distress, instrumental delivery, birth trauma, low Apgar score, and chorioamnionitis.

STUDY DESIGN

A study at the Women's Wellness and Research Center in Qatar analyzed 7721 low-risk normal vaginal deliveries from January 2017 to April 2018. Results were analyzed using descriptive and backward stepwise multinomial regression analysis, categorizing outcomes on the basis of pain management during active labor.

RESULTS

Of the 7607 participants in the final sample, 2606 received epidural analgesia, 1338 received intramuscular morphine, 286 received both, and 3304 received neither. Multinomial regression analysis revealed no difference in neonatal intensive care unit admission in the epidural analgesia group or in the intramuscular morphine group compared with the group that received neither intervention. However, the analysis showed a significant association between the combined use of epidural analgesia and intramuscular morphine and neonatal intensive care unit admission due to respiratory depression (adjusted odds ratio, 8.63; 95% confidence interval, 1.07-69.46; P=.04). Moreover, there was a significant association between prolonged duration of the second stage of labor and receiving epidural analgesia alone (adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.02; P<.001) or the combination of epidural analgesia and intramuscular morphine (adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.03; P<.001). In addition, the combined use of epidural analgesia and intramuscular morphine was associated with gestational age (adjusted odds ratio, 1.86; 95% confidence interval, 1.19-2.90; P=.01) and infant sex (adjusted odds ratio, 3.72; 95% confidence interval, 1.54-9.01; P=.003). Intramuscular morphine alone was only linked to low Apgar score at 1 minute (adjusted odds ratio, 6.29; 95% confidence interval, 1.33-29.83; P=.02).

CONCLUSION

In low-risk mothers, combining epidural analgesia and intramuscular morphine during labor increases NICU admission risk due to respiratory depression. However, the individual use of either method shows distinct clinical profile. Further research is warranted to enhance understanding and optimize pain management protocols.

Efficacy and safety of intravenous paracetamol in management of labour pains in a low resource setting: a randomized clinical trial

OBJECTIVE

To assess the use of single dose of paracetamol intravenously in management of labour pains.

BACKGROUND

Pain during labour is a complex, subjective and multi-faceted physiological phenomenon that varies in intensity among women and is subjected to many social and cultural modifiers.

SUBJECTS AND METHODS

This randomized clinical study was conducted in Obstetrics and gynecology department from March 2019 to March 2020 including 96 primiparous women randomized into paracetamol group (n = 48) received 1000 mg of paracetamol IV infusion and pethidine group (n = 48) received 50 mg of pethidine given slowly IV. Primary outcome is the change of the intensity of perceived labor pain. Pain score was followed and recorded by visual analogue scale (VAS). Our study protocol was registered at ClinicalTrials.gov; NCT04744727.

RESULTS

VAS score was highly significant improved gradually after 30 min, 1, 2 and 3 h of paracetamol and pethidine taken compared at start study, but participants in paracetamol group had lower pain after 2 and 3 h (3.92 ± 1.42 and 5.69 ± 1.07) than those of the pethidine groups (4.42 ± 1.87 and 5.38 ± 1.34). Also, 2.1% of paracetamol group developed dizziness and 4.2% developed nausea and vomiting, while there was 29.2% of pethidine group developed dizziness and 37.5% developed nausea and vomiting.

CONCLUSIONS

Intravenous paracetamol as labour analgesia is effective, safe, inexpensive, available and with no maternal or fetal side effects as compared to Pethidine. Paracetamol needs to have more chance in comparison to other forms as a labour pain analgesia, especially in our communities.

Pain management during labor and vaginal birth

Neuraxial analgesia provides excellent pain relief in labor. Optimizing initiation and maintenance of neuraxial labor analgesia requires different strategies. Combined spinal-epidurals or dural puncture epidurals may offer advantages over traditional epidurals. Ultrasound is useful in certain patients. Maintenance of analgesia is best achieved with a background regimen (either programmed intermittent boluses or a continuous epidural infusion) supplemented with patient-controlled epidural analgesia and using dilute local anesthetics combined with opioids such as fentanyl. Nitrous oxide and systemic opioids are also used for pain relief. Nitrous oxide may improve satisfaction despite variable effects on pain. Systemic opioids can be administered by healthcare providers or using patient-controlled analgesia. Appropriate choice of drug should take into account the stage and progression of labor, local safety protocols, and maternal and fetal/neonatal side effects. Pain in labor is complex, and women should fully participate in the decision-making process before any one modality is selected.

Intravenous remifentanil patient-controlled analgesia versus intramuscular pethidine for pain relief in labour (RESPITE): an open-label, multicentre, randomised controlled trial

BACKGROUND

About a third of women receiving pethidine for labour pain subsequently require an epidural, which provides effective pain relief but increases the risk of instrumental vaginal delivery. Remifentanil patient-controlled analgesia (PCA) in labour is an alternative to pethidine, but is not widely used. We aimed to evaluate epidural analgesia progression among women using remifentanil PCA compared with pethidine.

METHODS

We did an open-label, multicentre, randomised controlled trial in 14 UK maternity units. We included women aged 16 years or older, beyond 37 weeks' gestation, in labour with a singleton cephalic presentation, and who requested opioid pain relief. We randomly assigned eligible participants (1:1) to either the intravenous remifentanil PCA group (40 μg bolus on demand with a 2 min lockout) or the intramuscular pethidine group (100 mg every 4 h, up to 400 mg in 24 h), using a web-based or telephone randomisation service with a minimisation algorithm for parity, maternal age, ethnicity, and mode of labour onset. Because of the differences in routes of drug administration, study participants and health-care providers were not masked to the group allocation. The primary outcome was the proportion of women who received epidural analgesia after enrolment for pain relief in labour. Primary analyses were unadjusted and analysed by the intention-to-treat principle. This study is registered with the ISRCTN registry, number ISRCTN29654603.

FINDINGS

Between May 13, 2014, and Sept 2, 2016, 201 women were randomly assigned to the remifentanil PCA group and 200 to the pethidine group. One participant in the pethidine group withdrew consent, leaving 199 for analyses. The proportions of epidural conversion were 19% (39 of 201) in the remifentanil PCA group and 41% (81 of 199) in the pethidine group (risk ratio 0·48, 95% CI 0·34-0·66; p<0·0001). There were no serious adverse events or drug reactions directly attributable to either analgesic during the study.

INTERPRETATION

Intravenous remifentanil PCA halved the proportion of epidural conversions compared with intramuscular pethidine. This finding challenges routine pethidine use as standard of care in labour.

FUNDING

National Institute for Health Research Clinician Scientist Award.

Parenteral opioids for maternal pain management in labour

BACKGROUND

Parenteral opioids (intramuscular and intravenous drugs including patient-controlled analgesia) are used for pain relief in labour in many countries throughout the world. This review is an update of a review first published in 2010.

OBJECTIVES

To assess the effectiveness, safety and acceptability to women of different types, doses and modes of administration of parenteral opioid analgesia in labour. A second objective is to assess the effects of opioids in labour on the baby in terms of safety, condition at birth and early feeding.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (11 May 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the use of intramuscular or intravenous opioids (including patient-controlled analgesia) for women in labour. Cluster-randomised trials were also eligible for inclusion, although none were identified. We did not include quasi-randomised trials. We looked at studies comparing an opioid with another opioid, placebo, no treatment, other non-pharmacological interventions (transcutaneous electrical nerve stimulation (TENS)) or inhaled analgesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the quality of each evidence synthesis using the GRADE approach.

MAIN RESULTS

We included 70 studies that compared an opioid with placebo or no treatment, another opioid administered intramuscularly or intravenously or compared with TENS applied to the back. Sixty-one studies involving more than 8000 women contributed data to the review and these studies reported on 34 different comparisons; for many comparisons and outcomes only one study contributed data. All of the studies were conducted in hospital settings, on healthy women with uncomplicated pregnancies at 37 to 42 weeks' gestation. We excluded studies focusing on women with pre-eclampsia or pre-existing conditions or with a compromised fetus. Overall, the evidence was graded as low- or very low-quality regarding the analgesic effect of opioids and satisfaction with analgesia; evidence was downgraded because of study design limitations, and many of the studies were underpowered to detect differences between groups and so effect estimates were imprecise. Due to the large number of different comparisons, it was not possible to present GRADE findings for every comparison.For the comparison of intramuscular pethidine (50 mg/100 mg) versus placebo, no clear differences were found in maternal satisfaction with analgesia measured during labour (number of women satisfied or very satisfied after 30 minutes: 50 women; 1 trial; risk ratio (RR) 7.00, 95% confidence interval (CI) 0.38 to 128.87, very low-quality evidence), or number of women requesting an epidural (50 women; 1 trial; RR 0.50, 95% CI 0.14 to 1.78; very low-quality evidence). Pain scores (reduction in visual analogue scale (VAS) score of at least 40 mm: 50 women; 1 trial; RR 25, 95% CI 1.56 to 400, low-quality evidence) and pain measured in labour (women reporting pain relief to be "good" or "fair" within one hour of administration: 116 women; 1 trial; RR 1.75, 95% CI 1.24 to 2.47, low-quality evidence) were both reduced in the pethidine group, and fewer women requested any additional analgesia (50 women; 1 trial; RR 0.71, 95% CI 0.54 to 0.94, low-quality evidence).There was limited information on adverse effects and harm to women and babies. There were few results that clearly showed that one opioid was more effective than another. Overall, findings indicated that parenteral opioids provided some pain relief and moderate satisfaction with analgesia in labour. Opioid drugs were associated with maternal nausea, vomiting and drowsiness, although different opioid drugs were associated with different adverse effects. There was no clear evidence of adverse effects of opioids on the newborn. We did not have sufficient evidence to assess which opioid drug provided the best pain relief with the least adverse effects.

AUTHORS' CONCLUSIONS

Though most evidence is of low- or very-low quality, for healthy women with an uncomplicated pregnancy who are giving birth at 37 to 42 weeks, parenteral opioids appear to provide some relief from pain in labour but are associated with drowsiness, nausea, and vomiting in the woman. Effects on the newborn are unclear. Maternal satisfaction with opioid analgesia was largely unreported. The review needs to be examined alongside related Cochrane reviews. More research is needed to determine which analgesic intervention is most effective, and provides greatest satisfaction to women with acceptable adverse effects for mothers and their newborn.