Comparative efficacy of opioid and non-opioid analgesics in labor pain management: A network meta-analysis

BACKGROUND

Effective labor pain management is crucial for parturient well-being, as it can improve the delivery experience of pregnant women and reduce anxiety and tension. This systematic review and network meta-analysis compared the efficacy and safety of various analgesics, classified by drug category and individual treatment methods, for labor pain control.

METHODS

A comprehensive literature search was conducted in Pubmed, EMBASE, Cochrane Library, and Web of Science databases. All searches commenced from the database's inception to the date of the literature search (May 31, 2023). The Cochrane Risk of Bias 2 tool assessed study bias risk. Network meta-analyses using a random-effects model and odds ratios (ORs) with 95% confidence intervals (CIs) were performed.

RESULTS

Fifteen randomized controlled trials evaluating analgesic interventions in ASA I or II parturients were included. Combination therapies (OR: 5.81; 95% CI, 3.76-7.84; probability: 60%) and non-opioid analgesics (OR: 5.61; 95% CI, 2.91-8.30; probability: 39.2%) were superior to placebo for labor pain relief. Specifically, dexmedetomidine/ropivacaine/sufentanil (OR: 7.32; 95% CI, 2.73-11.89; probability: 40.6%) and dexmedetomidine/ropivacaine (OR: 6.50; 95% CI, 2.51-10.33; probability: 11.9%) combinations, bupivacaine/fentanyl and ropivacaine/sufentanil combinations, and remifentanil monotherapy showed improved analgesic efficacy versus placebo. Dexmedetomidine/ropivacaine reduced parturient nausea and vomiting versus alternatives.

CONCLUSION

Non-opioids, opioids and combinations thereof effectively relieved labor pain. In addition, dexmedetomidine/ropivacaine combination demonstrated analgesic efficacy and lower nausea and vomiting incidence.

Comparison of different delivery modalities of epidural analgesia and intravenous analgesia in labour: a systematic review and network meta-analysis

PURPOSE

In labour, neuraxial analgesia is the standard in the provision of pain relief. However, the optimal mode of delivering epidural solution has not been determined, and some parturients may need an alternative to epidural analgesia. We sought to conduct a systematic review and network meta-analysis to compare continuous epidural infusion (CEI), programmed intermittent epidural bolus (PIEB), computer-integrated CEI, computer-integrated PIEB, patient-controlled epidural bolus (PCEA), fentanyl patient-controlled analgesia (PCA), and remifentanil PCA, either alone or in combination.

METHODS

We searched CENTRAL, CINAHL, Ovid Embase, Ovid Medline, and Web of Science for randomized controlled trials that included nulliparous and/or multiparous parturients in spontaneous or induced labour. The maintenance epidural solution had to include a low concentration local anesthetic and an opioid. Specific subgroups in the obstetric population such as preeclampsia were excluded. Network meta-analysis was performed with a frequentist method, and continuous and dichotomous outcomes are presented as mean differences and odds ratios, respectively, with 95% confidence intervals.

RESULTS

Overall, 73 trials were included. For the first coprimary outcome, the need for rescue analgesia, CEI was inferior to PIEB and PIEB + PCEA was superior to PCEA alone, with a low certainty of evidence given the presence of serious limitations and imprecision. The second coprimary outcome, the maternal satisfaction, was improved by PIEB + PCEA compared with CEI + PCEA and PCEA alone, with a low quality of evidence in view of the presence of serious limitations and imprecision. Fentanyl PCA increased the requirement for rescue analgesia and decreased maternal satisfaction relative to many methods of delivering epidural solution. In terms of secondary outcomes, PIEB increased analgesic efficacy compared with CEI, and PCEA reduced local anesthetic consumption at the expense of inferior analgesia relative to CEI and PIEB. PIEB + PCEA was superior to CEI + PCEA in regard to the pain score at 2 h and 4 h, consumption of local anesthetic, incidence of lower lower limb motor blockade and the rate of spontaneous vaginal delivery. Fentanyl and remifentanil PCA did not provide the same level of analgesia as all epidural methods, resulted in increasing analgesic ineffectiveness with time spent in labour, and predisposed to a higher incidence of side effects such as nausea and/or vomiting and sedation. Remifentanil PCA was superior to fentanyl PCA for analgesia at an early time point, and it increased the incidence of oxygen desaturation relative to other strategies of delivering epidural solution.

CONCLUSIONS

Opioid PCA did not provide the same level of analgesia as epidural methods with a higher incidence of side effects. We interpret the findings of our systematic review and network meta-analysis as suggesting PIEB + PCEA to be the optimal delivery mode of epidural solution. Nevertheless, the potential differing importance of the various maternal, fetal, and neonatal outcomes in determining which is optimal has not, to our knowledge, been elucidated yet.

STUDY REGISTRATION

PROSPERO (CRD42021254978); registered 27 May 2021.

The Comparison of Two Different Techniques of Remifentanil Administration During Implantable Vascular Access Device Procedures

PURPOSE

The aim was to compare analgesic efficacy and adverse effects of two different techniques of intravenous remifentanil administration in patients undergoing vascular; access device procedures with monitored anesthesia care.

DESIGN

A randomized, single-blinded controlled study.

METHODS

The patients (N = 92) were 30-80 years old and of American Society of Anesthesiologists Physical Status I-III. The first group was the continuous infusion group (group CI). Intravenous continuous remifentanil was infused after starting at a dosage of 0.1 mcg/kg/min, and the dose was raised incrementally up to 1 mcg/kg/min if required. The second group was intravenous bolus patient-controlled sedation analgesia (PCSA) with remifentanil infusion at a dose of 0.05 mcg/kg per minute and bolus of 0.1 mcg/kg with lock-out time of 3 minutes. In both groups, a bolus dose of 0.1 mcg/kg remifentanil was administered. The data evaluated include level of pain and sedation, total amount of remifentanil consumption, bolus doses of remifentanil, patient and surgeon satisfaction, hemodynamic data, and adverse events.

FINDINGS

In comparison between techniques, pain and sedation scores during procedure, duration of procedure, patient and surgeon satisfaction, additional rescue medication, and bolus doses were not statistically different (P > .05). The total amount of remifentanil administered was significantly lower in the infusion group than that in the bolus group (P = .031).

CONCLUSIONS

For central venous access device procedures under monitored anesthesia care, remifentanil use in both infusion and bolus techniques could provide sufficient sedation and analgesia without serious adverse effects. Total remifentanil consumption amount in infusion group is lower than that in the bolus group.

Effect and Safety of Remifentanil Patient-Controlled Analgesia Compared with Epidural Analgesia in Labor: An Updated Meta-Analysis of Randomized Controlled Trials

PURPOSE

The study was aimed to systematically assess the effect and safety of remifentanil patient-controlled analgesia (rPCA) versus epidural analgesia (EA) during labor.

METHODS

Eligible trials were retrieved from PubMed, EMBASE, ScienceDirect, and Cochrane Library before April 2020. The primary outcomes were patient satisfaction with pain relief and average visual analog scale (VAS) pain scores during labor; the secondary outcomes were rate of spontaneous delivery, oxygen desaturation, maternal hyperthermia, and neonatal Apgar scores <7 at 1 and 5 min.

RESULTS

Eleven studies involving 3,039 parturients were included. We found that parturients receiving rPCA were similarly satisfied with pain relief compared to those receiving EA (standardized mean difference: -0.19; 95% confidence interval [CI]: -0.57, 0.18), though had significantly higher VAS pain scores during labor (weighted mean difference: 1.41; 95% CI: 0.32, 2.50). The rate of spontaneous delivery was comparable. rPCA increased the risk of maternal oxygen desaturation (risk ratio [RR]:3.23, 95% CI: 1.98, 5.30). There was no statistical significance regarding hyperthermia (RR: 0.49, 95% CI: 0.24, 1.01). No significant difference was found for neonatal Apgar scores <7 at 1 and 5 min.

CONCLUSION

rPCA could be an optional alternative for pain relief to EA without worsening maternal satisfaction with pain relief, delivery modes, or neonatal morbidity. However, rPCA was associated with higher pain intensity during labor and higher incidence of maternal oxygen desaturation. The routine use of rPCA in labor must be armed with close respiratory monitoring. Continued well-designed studies are required to provide more robust evidence.

The Effect of Pethidine Analgesia on Labor Duration and Maternal-Fetal Outcomes

Background and Aim:

Opioid analgesics had been used from time to time for treating labor pain. However, their use have been concerning. The aim of this study is to evaluate the effect of pethidine on duration of active phase of labor, labor pain and maternal-neonatal outcomes.

Methods:

In the present case-control study, the study group received a 50 mg pethidine intramuscular injection upon the start of active phase of labor, and the control group consisted of patients who receive placebo injeciton. In both groups, vital signs were measured before, and at 0, 5, 15, 30, 45 and 60 minutes after the injection. Pain intensity was evaluated with Visual Analogue Scale (VAS) prior to, and 1 hour and 2 hours after injection. Data regarding labor phase durations, maternal side effects, newborn APGAR scores and fetal respiratory problems were recorded.

Results:

102 patients in Pethidine group and 92 patients in control group, were included into the study. Labor pain VAS-scores were significantly lower in the study group (p<0.001). Moreover, active phase of labor duration was significantly shorter in the study group (p<0.001). Maternal pulse significantly decreased, and maternal nausea-vomiting was frequent in the study groups. However, the groups were similar in terms of other side effects and neonatal outcomes.

Conclusions:

Pethidine significantly reduces active phase of labor duration, has a favorable analgesic effect in treating labor pain and is not associated with serious maternal or neonatal complications. It is therefore considered an acceptable agent for use during active phase of labor. (www.actabiomedica.it)

Case Report of Remifentanil Labor Analgesia for a Pregnant Patient With Congenital Methemoglobinemia Type 1

Congenital methemoglobinemia is a rare disease characterized by cyanosis and a left shifting of the oxyhemoglobin dissociation curve. The disease necessitates avoidance of certain medications commonly used in obstetrics, making labor analgesia and anesthesia challenging. We present a case report of peripartum anesthetic management of a pregnant patient with congenital methemoglobinemia type 1 who received remifentanil labor analgesia and continuous methemoglobin monitoring. Continuous real-time monitoring of methemoglobin concentrations may prove to be a useful monitor in future care settings. A review of literature encompassing various perioperative and obstetric anesthesia and analgesia management considerations is presented.

Pethidine in Low Doses versus Dipyrone for Pain Relief in Labor: A Randomized Controlled Trial

OBJECTIVE

 To compare low doses of pethidine with dipyrone in labor analgesia.

METHODS

 In a randomized prospective study conducted by Universidade de Fortaleza, in the state of Ceará, Brazil, between May and December 2016, 200 full-term parturients, with very painful uterine contractions and exhibiting uterine cervix dilatation ≥ 5 cm, were selected to receive a single intravenous dose of either 0.25 mg/kg of pethidine (n = 100) or of 25 mg/kg of dipyrone (n = 100). Pain was assessed using the visual analogue scale. The data were analyzed using the Student t-test, the chi-square test and the likelihood ratio.

RESULTS

 There was a significant improvement in pain in 35% of the parturients. Both drugs presented a similar analgesic effect 1 hour after the intervention (p = 0.692). There was no analgesic effect during the evaluation of the second hour after the intervention with pethidine or dipyrone. There were no adverse effects, such as maternal drowsiness, nausea or vomiting, related to the drugs used.

CONCLUSION

 Pethidine in low doses and dipyrone presented equivalent analgesia during labor.

PUBLIC REGISTRY OF CLINICAL TRIALS

 RBR-4hsyy4.

Patient-controlled analgesia with remifentanil vs. alternative parenteral methods for pain management in labour: a Cochrane systematic review

We aimed to assess the effectiveness of remifentanil used as intravenous patient-controlled analgesia for the pain of labour. We performed a systematic literature search in December 2015 (updated in December 2016). We included randomised, controlled and cluster-randomised trials of women in labour with planned vaginal delivery receiving patient-controlled remifentanil compared principally with other parenteral and patient-controlled opioids, epidural analgesia and continuous remifentanil infusion or placebo. The primary outcomes were patient satisfaction with pain relief and the occurrence of adverse events for mothers and newborns. We assessed risk of bias for each included study and applied the GRADE approach for the quality of evidence. We included total zero event trials, using a constant continuity correction of 0.01 and a random-effect meta-analysis. Twenty studies were included in the qualitative analysis; within these, 3713 participants were randomised and 3569 analysed. Most of our pre-specified outcomes were not studied in the included trials. However, we found evidence that women using patient-controlled remifentanil were more satisfied with pain relief than women receiving parenteral opioids (four trials, 216 patients, very low quality evidence) with a standardised mean difference ([SMD] 95%CI) of 2.11 (0.72-3.49), but were less satisfied than women receiving epidural analgesia (seven trials, 2135 patients, very low quality evidence), -0.22 (-0.40 to -0.04). Data on adverse events were sparse. However, the relative risk (95%CI) for maternal respiratory depression for patient-controlled remifentanil compared with epidural analgesia (three trials, 687 patients, low-quality evidence) was 0.91 (0.51-1.62). Compared with continuous intravenous infusion of remifentanil (two trials, 135 patients, low-quality evidence) no conclusion could be reached as all study arms showed zero events. The relative risk (95%CI) of Apgar scores less than 7 at 5 min after birth compared with epidural analgesia (five trials, 1322 participants, low-quality evidence) was 1.26 (0.62-2.57).

A Review of the Impact of Obstetric Anesthesia on Maternal and Neonatal Outcomes

Obstetric anesthesia has evolved over the course of its history to encompass comprehensive aspects of maternal care, ranging from cesarean delivery anesthesia and labor analgesia to maternal resuscitation and patient safety. Anesthesiologists are concerned with maternal and neonatal outcomes, and with preventing and managing complications that may present during childbirth. The current review will focus on recent advances in obstetric anesthesia, including labor anesthesia and analgesia, cesarean delivery anesthesia and analgesia, the effects of maternal anesthesia on breastfeeding and fever, and maternal safety. The impact of these advances on maternal and neonatal outcomes is discussed. Past and future progress in this field will continue to have significant implications on the health of women and children.

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.

Electro-acupuncture stimulation prevents remifentanil-induced postoperative hyperalgesia by suppressing spinal microglia in rats

The aim of the present study was to assess the effect of electro-acupuncture (EA) stimulation on remifentanil-induced postoperative hyperalgesia (RIPH) and the possible involvement of spinal microglia suppression. A model of RIPH was established using adult male Sprague-Dawley rats by administration of remifentanil at 0.08 mg/kg intravenously for 60 min. The Huantiao and Yanglingquan acupoints were stimulated continuously by EA (2 Hz, ~1 mA) for 90 min from before paw incision to the end of remifentanil administration. Sham acupoints were stimulated by EA in the sham group. Paw withdrawal threshold (PWT) and paw thermal withdrawal latency (PWL) were determined. Cluster of differentiation (CD)11b, tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 levels in spinal cord samples were measured using immunohistochemistry and ELISA. PWT and PWL values were decreased following the administration of remifentanill; however, following EA, PWT and PWL values increased compared with the sham group (P<0.05), indicating that EA alleviates remifentanil-induced RIPH. CD11b, TNF-α, IL-1β and IL-6 levels were increased following remifentanil administration and these effects were counteracted by EA (all P<0.05). In the sham group, no significant differences were observed in PWT and PWL values or CD11b, TNF-α, IL-1β and IL-6 levels compared with the control group, suggesting that EA was responsible for the reduction in CD11b and pro-inflammatory cytokine expression following remifentanil administration. The results of the present study demonstrated that EA at the Huantiao and Yanglingquan acupoints may reduce remifentanil-induced postoperative hyperalgesia, likely by inhibiting spinal microglia via reduction of CD11b and pro-inflammatory cytokine expression. However, these results are preliminary and require further validation.

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.

Non-Neuraxial Labor Analgesia: Options

Although it is the most effective method to treat labor pain, neuraxial analgesia may be undesired, contraindicated, unsuccessful, or unavailable. Providing safe choices for labor pain relief is a central goal of health care providers alike. Consequently, knowledge of the efficacy, clinical implementation, and side effects of various non-neuraxial strategies is needed to provide appropriate options for laboring patients. In addition to nonpharmacologic alternatives, inhaled nitrous oxide and systemic opioids represent two broad classes of non-neuraxial pharmacologic labor analgesia most commonly available. This review summarizes the current published literature for these non-neuraxial labor analgesic options.

Retrospective study of anaesthetic management of pregnancy patients with mechanical heart valve prosthesis and anticoagulants

Pregnancies among patients with a mechanical prosthetic valve and receiving anticoagulant medication are rare. Informations about their anesthetic management is poor. The objective of this study was to investigate the anaesthetic management of these patients in a reference medical centre as well as to identify possible ways for improvement. To this aim, the medical records of patients with a mechanical heart valve prosthesis having given birth at our center were analysed. In particular, the characteristics of patients and deliveries, the management of anticoagulation, as well as the type of anaesthesia performed, were collected and analysed. Eighteen cases were studied and compared to 36 controls. All studied cases were being administered anticoagulants. Five of these 8 patients delivered vaginally, one with epidural analgesia. Three of them have had a caesarean during labor, all under general anaesthesia. During the anticoagulation window, the teams had to perform an epidural in 3 (37%) of these 8 patients. Ten cases (55%) had a planned caesarean delivery, all performed under general anaesthesia. The anticoagulation interruption allowed spinal anaesthesia for 4 out of 10 caesarean delivery. The reoperation rate for secondary haemorrhage was significantly higher (P=0.0032) and the duration of the hospitalisation was extended (P<0.001). A context of anticoagulant overdose was identified in 60% of the bleeding cases. Progress can be made in the anaesthetic management of those patients by optimising the use of neuraxial anaesthesia and by improving the management of bleeding risk after delivery.

A Survey of Intravenous Remifentanil Use for Labor Analgesia at Academic Medical Centers in the United States

Remifentanil is most commonly offered when neuraxial labor analgesia is contraindicated. There is no consensus regarding the optimal administration, dosing strategy, or requirements for maternal monitoring, which may pose a patient safety issue. This exploratory survey evaluated the current practices regarding remifentanil use for labor analgesia at academic centers in the United States. Of 126 obstetric anesthesia directors surveyed, 84 (67%) responded. In 2014 to 2015, an estimated 36% (95% confidence interval: 25.7-46.3) of centers used remifentanil, most of which did so less than 5 times. Some serious maternal and neonatal respiratory complications occurred, emphasizing that clinical protocols and adequate monitoring are key to ensure maternal and neonatal safety.

A case series of vital signs-controlled, patient-assisted intravenous analgesia (VPIA) using remifentanil for labour and delivery

Intravenous remifentanil patient-controlled analgesia can be used during labour as an alternative to epidural analgesia. Adverse effects of opioids, including hypoxia and bradycardia, may lead to maternal morbidity and mortality. We devised an interactive feedback system based on a clinical proportional algorithm, to continuously monitor for adverse effects to enhance safety and better titrate analgesia. This vital signs-controlled, patient-assisted intravenous analgesia with remifentanil used a prototype delivery system linked to a pulse oximeter that evaluated maternal oxygen saturation and heart rate continuously. With this system, we detected oxygen saturation < 95% for more than 60 s in 15 of 29 subjects (52%); and heart rate < 60 min^-1 for more than 60 s in 7 of 29 subjects (24%) during use. The system automatically responded appropriately by reducing the dosages and temporarily halting remifentanil administration, thus averting further hypoxia and bradycardia.

Patient-controlled analgesia with remifentanil versus alternative parenteral methods for pain management in labour

BACKGROUND

Multiple analgesic strategies for pain relief during labour are available. Recently remifentanil, a short-acting opioid, has recently been used as an alternative analgesic due to its unique pharmacological properties.

OBJECTIVES

To systematically assess the effectiveness of remifentanil intravenous patient-controlled analgesia (PCA) for labour pain, along with any potential harms to the mother and the newborn.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (9 December 2015), ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP), handsearched congress abstracts (November 2015), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and cluster-randomised trials comparing remifentanil (PCA) with another opioid (intravenous (IV)/intramuscular (IM)), or with another opioid (PCA), or with epidural analgesia, or with remifentanil (continuous IV), or with remifentanil (PCA, different regimen), or with inhalational analgesia, or with placebo/no treatment in all women in labour including high-risk groups with planned vaginal delivery.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, extracted data, and appraised study quality.We contacted study authors for additional information other than incomplete outcome data. We performed random-effects meta-analysis.To reduce the risk of random error in meta-analysis we performed trial sequential analysis. We included total zero event trials and used a constant continuity correction of 0.01 (ccc 0.01) for meta-analysis. We applied the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) approach to assess the quality of evidence.

MAIN RESULTS

Twenty RCTs with 3569 women were included. Of those, 10 trials (2983 participants) compared remifentanil (PCA) to an epidural, four trials (216 participants) to another opioid (IV/IM), three trials (215 participants) to another opioid (PCA), two trials (135 participants) to remifentanil (continuous IV), and one trial (20 participants) to remifentanil (PCA, different regimen). No trials were identified for the remaining comparisons.Methodological quality of studies was moderate to poor. We assessed risk of bias as high for blinding issues and incomplete outcome data in 65% and 45% of the included studies, respectively.There is evidence of effect that women in the remifentanil (PCA) group were more satisfied with pain relief than women in the other opioids (IV/IM) group (standardised mean difference (SMD) 2.11, 95% confidence interval (CI) 0.72 to 3.49, four trials, very low-quality evidence), and that women were less satisfied compared to women in the epidural group (SMD -0.22, 95% CI -0.40 to -0.04, seven trials, very low-quality evidence).There is evidence of effect that remifentanil (PCA) provided stronger pain relief at one hour than other opioids administered IV/IM (SMD -1.58, 95% CI -2.69 to -0.48, three trials, very low-quality evidence) or via PCA (SMD -0.51, 95% CI -1.01 to -0.00, three trials, very low-quality evidence). Pain intensity was higher in the remifentanil (PCA) group compared to the epidural group (SMD 0.57, 95% CI 0.31 to 0.84, six trials, low-quality evidence).Data were limited on safety aspects for both the women and the newborns. Only one study analysed maternal apnoea in a comparison of remifentanil (PCA) versus epidural and reported that half of the women in the remifentanil and none in the epidural group had an apnoea (very low-quality evidence). There is no evidence of effect that remifentanil (PCA) was associated with an increased risk for maternal respiratory depression when compared to epidural analgesia (RR 0.91, 95% CI 0.51 to 1.62, ccc 0.01, three trials, low-quality evidence) and no reliable conclusion might be reached compared to remifentanil (continuous IV) (all study arms included zero events, two trials, low-quality evidence). In one trial of remifentanil (PCA) versus another opioid (IM) three out of 18 women in the remifentanil and none out of 18 in the control group had a respiratory depression (very low-quality evidence).There is no evidence of effect that remifentanil (PCA) was associated with an increased risk for newborns with Apgar scores less than seven at five minutes compared to epidural analgesia (RR 1.26, 95% CI 0.62 to 2.57, ccc 0.01, five trials, low-quality evidence) and no reliable conclusion might be reached compared to another opioid (IV) and compared to remifentanil (PCA, different regimen) both with zero events in all study arms (one trial, very-low quality evidence). In one trial of remifentanil (PCA) versus another opioid (PCA) none out of nine newborns in the remifentanil and three out of eight in the opioid (PCA) group had Apgar scores less than seven (very-low quality evidence).There is evidence that remifentanil (PCA) was associated with a lower risk for the requirement of additional analgesia when compared to other opioids (IV/IM) (RR 0.57, 95% CI 0.40 to 0.81, three trials, moderate-quality evidence) and that it was associated with a higher risk compared to epidural analgesia (RR 9.27, 95% CI 3.73 to 23.03, ccc 0.01, six trials, moderate-quality evidence). There is no evidence of effect that remifentanil (PCA) reduced the requirement for additional analgesia compared to other opioids (PCA) (RR 0.76, 95% CI 0.45 to 1.28, three trials, low-quality evidence).There is evidence that there was no difference in the risk for caesarean delivery between remifentanil (PCA) and other opioids (IV/IM) (RR 0.63, 95% CI 0.30 to 1.32, ccc 0.01, four trials, low-quality evidence) and epidural analgesia (RR 1.0, 95% CI 0.82 to 1.22, ccc 0.01, nine trials, moderate-quality evidence), respectively. Pooled meta-analysis revealed an increased risk for caesarean section under remifentanil (PCA) compared to other opioids (PCA) (RR 2.78, 95% CI 0.99 to 7.82, two trials, very low-quality evidence). However, a wide range of clinically relevant and non-relevant treatment effects is compatible with this result.

AUTHORS' CONCLUSIONS

Based on the current systematic review, there is mostly low-quality evidence to inform practice and future research may significantly alter the current situation. The quality of evidence is mainly limited by poor quality of the studies, inconsistency, and imprecision. More research is needed on maternal and neonatal safety outcomes (maternal apnoea and respiratory depression, Apgar score) and on the optimal mode and regimen of remifentanil administration to provide highest efficacy with reasonable adverse effects for mothers and their newborns.

Should Nitrous Oxide Be Used for Laboring Patients?

Nitrous oxide, long used during labor in Europe, is gaining popularity in the United States. It offers many beneficial attributes, with few drawbacks. Cost, safety, and side effect profiles are favorable. Analgesic effectiveness is highly variable, yet maternal satisfaction is often high among the women who choose to use it. Despite being less effective in treating labor pain than neuraxial analgesic modalities, nitrous oxide serves the needs and preferences of a subset of laboring parturients. Nitrous oxide should, therefore, be considered for inclusion in the repertoire of modalities used to alleviate pain and facilitate effective coping during labor.

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

BACKGROUND

The commonest opioid used for pain relief in labour is pethidine (meperidine); however, its effectiveness has long been challenged and the drug has known side effects including maternal sedation, nausea and potential transfer across the placenta to the foetus. Over a third of women receiving pethidine require an epidural due to inadequate pain relief. Epidural analgesia increases the risk of an instrumental vaginal delivery and its associated effects. Therefore, there is a clear need for a safe, effective, alternative analgesic to pethidine. Evidence suggests that remifentanil patient-controlled analgesia (PCA) reduces epidural conversion rates compared to pethidine; however, no trial has yet investigated this as a primary endpoint. We are, therefore, comparing pethidine intramuscular injection to remifentanil PCA in a randomised controlled trial.

METHODS/DESIGN

Women in established labour, requesting systemic opioid pain relief, will be randomised to either intravenously administered remifentanil PCA (intervention) or pethidine intramuscular injection (control) in an unblinded, 1:1 individual randomised trial. Following informed consent, 400 women in established labour, who request systemic opioid pain relief, from NHS Trusts across England will undergo a minimised randomisation by a computer or automated telephone system to either pethidine or remifentanil. In order to balance the groups this minimisation is based on four parameters; parity (nulliparous versus multiparous), maternal age (<20, 20 < 30, 30 < 40, 40+ years), ethnicity (South Asian (Pakistani/Indian/Bangladeshi) versus Other) and induced versus spontaneous labour. The effectiveness of pain relief provided by each technique will be recorded every 30 min after time zero, until epidural placement, delivery or transfer to theatre, quantified by Visual Analogue Scale. Incidence of maternal side effects including sedation, delivery mode, foetal distress requiring delivery, neonatal status at delivery and rate of initiation of breastfeeding within the first hour of birth will also be recorded. Maternal satisfaction with her childbirth experience will be determined by a postpartum questionnaire prior to discharge from the delivery ward.

DISCUSSION

The RESPITE trial's primary outcome is the proportion of women who have an epidural placed for pain relief in labour in each arm.

TRIAL REGISTRATION

Current Controlled Trials registration number: ISRCTN29654603 . Registered on 23 July 2013.

Patient controlled analgesia with remifentanil versus epidural analgesia in labour: randomised multicentre equivalence trial

OBJECTIVE

To determine women's satisfaction with pain relief using patient controlled analgesia with remifentanil compared with epidural analgesia during labour.

DESIGN

Multicentre randomised controlled equivalence trial.

SETTING

15 hospitals in the Netherlands.

PARTICIPANTS

Women with an intermediate to high obstetric risk with an intention to deliver vaginally. To exclude a clinically relevant difference in satisfaction with pain relief of more than 10%, we needed to include 1136 women. Because of missing values for satisfaction this number was increased to 1400 before any analysis. We used multiple imputation to correct for missing data.

INTERVENTION

Before the onset of active labour consenting women were randomised to a pain relief strategy with patient controlled remifentanil or epidural analgesia if they requested pain relief during labour.

MAIN OUTCOME MEASURES

Primary outcome was satisfaction with pain relief, measured hourly on a visual analogue scale and expressed as area under the curve (AUC), thus providing a time weighted measure of total satisfaction with pain relief. A higher AUC represents higher satisfaction with pain relief. Secondary outcomes were pain intensity scores, mode of delivery, and maternal and neonatal outcomes. Analysis was done by intention to treat. The study was defined as an equivalence study for the primary outcome.

RESULTS

1414 women were randomised, of whom 709 were allocated to patient controlled remifentanil and 705 to epidural analgesia. Baseline characteristics were comparable. Pain relief was ultimately used in 65% (447/687) in the remifentanil group and 52% (347/671) in the epidural analgesia group (relative risk 1.32, 95% confidence interval 1.18 to 1.48). Cross over occurred in 7% (45/687) and 8% (51/671) of women, respectively. Of women primarily treated with remifentanil, 13% (53/402) converted to epidural analgesia, while in women primarily treated with epidural analgesia 1% (3/296) converted to remifentanil. The area under the curve for total satisfaction with pain relief was 30.9 in the remifentanil group versus 33.7 in the epidural analgesia group (mean difference -2.8, 95% confidence interval -6.9 to 1.3). For who actually received pain relief the area under the curve for satisfaction with pain relief after the start of pain relief was 25.6 in the remifentanil group versus 36.1 in the epidural analgesia group (mean difference -10.4, -13.9 to -7.0). The rate of caesarean section was 15% in both groups. Oxygen saturation was significantly lower (SpO2 <92%) in women who used remifentanil (relative risk 1.5, 1.4 to 1.7). Maternal and neonatal outcomes were comparable between both groups.

CONCLUSION

In women in labour, patient controlled analgesia with remifentanil is not equivalent to epidural analgesia with respect to scores on satisfaction with pain relief. Satisfaction with pain relief was significantly higher in women who were allocated to and received epidural analgesia.

TRIAL REGISTRATION

Netherlands Trial Register NTR2551.

Intravenous remifentanil versus epidural ropivacaine with sufentanil for labour analgesia: a retrospective study

Remifentanil with appropriate pharmacological properties seems to be an ideal alternative to epidural analgesia during labour. A retrospective cohort study was undertaken to assess the efficacy and safety of remifentanil intravenous patient-controlled analgesia (IVPCA) compared with epidural analgesia. Medical records of 370 primiparas who received remifentanil IVPCA or epidural analgesia were reviewed. Pain and sedation scores, overall satisfaction, the extent of pain control, maternal side effects and neonatal outcome as primary observational indicators were collected. There was a significant decline of pain scores in both groups. Pain reduction was greater in the epidural group throughout the whole study period (0∼180 min) (P<0.0001), and pain scores in the remifentanil group showed an increasing trend one hour later. The remifentanil group had a lower SpO₂ (P<0.0001) and a higher sedation score (P<0.0001) within 30 min after treatment. The epidural group had a higher overall satisfaction score (3.8±0.4 vs. 3.7±0.6, P = 0.007) and pain relief score (2.9±0.3 vs. 2.8±0.4, P<0.0001) compared with the remifentanil group. There was no significant difference on side effects between the two groups, except that a higher rate of dizziness (1% vs. 21.8%, P<0.0001) was observed during remifentanil analgesia. And logistic regression analysis demonstrated that nausea, vomiting were associated with oxytocin usage and instrumental delivery, and dizziness was associated to the type and duration of analgesia. Neonatal outcomes such as Apgar scores and umbilical-cord blood gas analysis were within the normal range, but umbilical pH and base excess of neonatus in the remifentanil group were significantly lower. Remifentanil IVPCA provides poorer efficacy on labor analgesia than epidural analgesia, with more sedation on parturients and a trend of newborn acidosis. Despite these adverse effects, remifentanil IVPCA can still be an alternative option for labor analgesia under the condition of one-to-one bedside care, continuous monitoring, oxygen supply and preparation for neonatal resuscitation.

The Comparison of Patient-Controlled Remifentanil Administered by Two Different Protocols (Bolus and Bolus+Infusion) and Intramuscular Meperidine for Labor Analgesia

OBJECTIVE

Nowadays, there are many pain relief methods for reducing the pain and stress of labor and delivery. In our study, two different remifentanil protocols (bolus and bolus+infusion) administered by patient-controlled analgesia method were compared with intramuscular meperidine for labor analgesia.

METHODS

Ninety parturients who were scheduled for vaginal delivery were included in this study. Patients were randomly divided into 3 groups, with 15 primiparous and 15 multiparous patients in each group. Whenever a patient requested analgesics during the labor, Group M was given 1 mg kg(-1) intramuscular meperidine, Group B was given intravenous bolus patient-controlled remifentanil, and Group IB was given intravenous bolus+infusion patient-controlled remifentanil. Patients' systolic and diastolic blood pressure, heart rate, pain-comfort and sedation scores, remifentanil consumption, side effects, and Apgar scores of the newborns were evaluated during the labor and delivery.

RESULTS

Patients' mean pain and comfort scores were significantly lower in Groups B and IB than in Group M at all time intervals except the first minute. Compared with Group IB, mean pain and comfort scores at 15, 30, 60, and 120 minutes were significantly higher in Group B. The mean sedation scores were similar among the groups. Total remifentanil consumption was lower in Group IB than in Group B, but it was not statistically significant.

CONCLUSION

Patient-controlled intravenous bolus or bolus+infusion remifentanil provided more effective analgesia and patient comfort than intramuscular meperidine for labor analgesia. Especially during labor, bolus+infusion remifentanil administration provided better pain and patient comfort scores than bolus alone, without increasing remifentanil consumption.

Patient-Controlled Remifentanil Analgesia as Alternative for Pethidine with Midazolam During Oocyte Retrieval in IVF/ICSI Procedures: A Randomized Controlled Trial

BACKGROUND

Pethidine with midazolam-induced conscious sedation for pain relief during transvaginal oocyte retrieval for in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) procedures is associated with residual pain and oversedation. Patient-controlled analgesia (PCA) with remifentanil may serve as an alternative for pethidine. We investigated whether PCA remifentanil with diclofenac was associated with improved periprocedural pain relief than pethidine analgesia during IVF/ICSI procedures, with sedation scores, safety profiles, and patient satisfaction as secondary endpoints.

METHODS

Seventy-six women were randomized to receive pethidine (2 mg/kg i.m.) and midazolam (7.5 mg)-induced conscious sedation (n = 40) or PCA with remifentanil and diclofenac (50 mg; n = 36). The Numeric Rating Scale, McGill Pain Questionnaire (MPQ), Ramsey Sedation Scale, and a 5-day pain-and-discomfort diary were used to evaluate pain and sedation levels.

RESULTS

There were no differences in baseline characteristics and reproductive outcomes between both groups. Periprocedural pain scores were comparable for remifentanil and pethidine groups (4 [3 to 7] vs. 6 [4 to 8]; P = 0.13). Pain scores in the pethidine group were significantly lower at 30 minutes after the procedure (1 [0 to 3] vs. 2 [1 to 5]; P = 0.016), but at cost of higher sedation levels when compared to remifentanil (4 [2 to 4] vs. 2 [2 to 2]; P < 0.001). Patient satisfaction was higher, and MPQ scores were lower in the remifentanil group. There were no differences in safety profiles between both analgesics.

CONCLUSIONS

Patient-controlled analgesia with remifentanil showed a similar reduction in pain scores than pethidine with midazolam during oocyte retrieval, while pethidine induced the highest pain relief after the procedure. However, PCA remifentanil was associated with less sedation and a better patient satisfaction profile than pethidine.

Safety of the breast-feeding infant after maternal anesthesia

There has been an increase in breast-feeding supported by the recommendations of the American Academy of Pediatrics and the World Health Organization. An anesthesiologist may be presented with a well-motivated breast-feeding mother who wishes to breast-feed her infant in the perioperative period. Administration of anesthesia entails acute administration of drugs with potential for sedation and respiratory effects on the nursing infant. The short-term use of these drugs minimizes the possibility of these effects. The aim should be to minimize the use of narcotics and benzodiazepines, use shorter acting agents, use regional anesthesia where possible and avoid agents with active metabolites. Frequent clinical assessments of the nursing infant are important. Available literature does suggest that although the currently available anesthetic and analgesic drugs are transferred in the breast milk, the amounts transferred are almost always clinically insignificant and pose little or no risk to the nursing infant.

Analgesia for childbirth: modern insights into an age-old challenge and the quest for an ideal approach

SUMMARY It is widely recognized that childbirth may be the most painful experience in a woman’s lifetime and that women have a right to relief. There are many options, but the efficacy of only a few is supported by robust evidence. Many influences determine which method of pain relief is chosen, including social and cultural factors, availability, cost and personal preference. Due to human diversity and the differing perspectives of consumers, obstetric care providers and health administrators, there is no such thing as ‘an ideal approach’. In resource-rich societies, major advances in parturient safety and outcome flow from technique development and better monitoring. Greater awareness of the negative impact of untreated pain and of the relevance of genetic, cultural and social factors motivates research into better predictive models, novel therapies and optimization of existing methods.

The effect of intravenous fentanyl on pain and duration of the active phase of first stage labor

OBJECTIVES

Opioids are most widely used for pain relief during childbirth. An alternative opioid, fentanyl, has been shown to be a good option for pain management and has fewer side-effects on both mother and fetus. Therefore, the purpose of this study is to determine the effect of fentanyl on pain as well as the duration of the active phase of labor.

METHODS

This clinical trial was conducted on 70 multiparous parturients having labor from May to July 2006 at Tamin Ejtemai Hospital. They were selected by convenience sampling at the beginning of the active phase of labor. The samples were then randomly divided into the case and control groups. The case group received fentanyl 50 micrograms in two doses, one hour apart after being diluted (0 and 60 mins). Vital signs were recorded pre-administration and 5, 15, 30, 45, 60 minutes post-administration. Pain intensity was estimated by visual pain scale (0-10) four times (before and 1, 2, 3 hours after the intervention). Data analysis was done using the student t-test, repeated measure ANOVA and chi-square tests via SPSS 11.5 software.

RESULTS

The results showed a significant reduction in pain (p=0.002) and HR (p=0.001) in the case group. The mean pain score also decreased from 8±1 to 5±1. There was a significant difference in terms of the duration of the active phase between the two groups (p=0.001). However, there were no significant differences in terms of systolic blood pressure and diastolic blood pressure between the two groups.

CONCLUSION

Fentanyl provides good analgesic effect for pain management during labor by considerably reducing the duration of the active phase, and can therefore be used as an acceptable analgesic agent during labor.

Must we press on until a young mother dies? Remifentanil patient controlled analgesia in labour may not be suited as a "poor man's epidural"

BACKGROUND

The epidural route is still considered the gold standard for labour analgesia, although it is not without serious consequences when incorrect placement goes unrecognized, e.g. in case of intravascular, intrathecal and subdural placements. Until now there has not been a viable alternative to epidural analgesia especially in view of the neonatal outcome and the need for respiratory support when long-acting opioids are used via the parenteral route. Pethidine and meptazinol are far from ideal having been described as providing rather sedation than analgesia, affecting the cardiotocograph (CTG), causing fetal acidosis and having active metabolites with prolonged half-lives especially in the neonate. Despite these obvious shortcomings, intramuscular and intravenously administered pethidine and comparable substances are still frequently used in delivery units. Since the end of the 90 ths remifentanil administered in a patient-controlled mode (PCA) had been reported as a useful alternative for labour analgesia in those women who either don't want, can't have or don't need epidural analgesia.

DISCUSSION

In view of the need for conversion to central neuraxial blocks and the analgesic effect remifentanil has been demonstrated to be superior to pethidine. Despite being less effective in terms of the resulting pain scores, clinical studies suggest that the satisfaction with analgesia may be comparable to that obtained with epidural analgesia. Owing to this fact, remifentanil has gained a place in modern labour analgesia in many institutions. However, the fact that remifentanil may cause harm should not be forgotten when the use of this potent mu-agonist is considered for the use in labouring women. In the setting of one-to-one midwifery care, appropriate monitoring and providing that enough experience exists with this potent opioid and the treatment of potential complications, remifentanil PCA is a useful option in addition to epidural analgesia and other central neuraxial blocks. Already described serious consequences should remind us not refer to remifentanil PCA as a "poor man's epidural" and to safely administer remifentanil with an appropriate indication.

SUMMARY

Therefore, the authors conclude that economic considerations and potential cost-savings in conjunction with remifentanil PCA may not be appropriate main endpoints when studying this valuable method for labour analgesia.