Remifentanil versus placebo for analgesia during external cephalic version: a randomised clinical trial

Effect of anesthesia on the success rate of external cephalic version: GRADE- assessed systematic review and meta-analysis of randomized controlled trials

BACKGROUND

External cephalic version (ECV) is a medical procedure in which an extracorporeal manipulation is performed to render the breech presentation (BP) fetus in the cephalic position. The use of anesthesia to facilitate repositioning has been evaluated in various randomized clinical trials (RCTs), but its potential effectiveness remains controversial.

METHODS

A systematic literature search was carried out in 8 electronic databases. In the meta-analysis, a random effects model was used to calculate the pooled relative risk (RR) and its 95% confidence interval (CI), and the pooled standardized mean difference (SMD) and its 95% CI, in order to systematically assess the effect of anesthesia on the success rates of ECV, vaginal delivery, cesarean delivery as well as other outcomes. Relevant subgroup analyses, publication bias test and sensitivity analyses were also conducted.

RESULTS

This review included 17 RCTs. Women who received anesthesia had a significantly higher incidence of successful ECV (RR: 1.37, 95% CIs: 1.19-1.58) and vaginal delivery (RR: 1.23, 95% CIs: 1.03-1.47), and a significantly lower incidence of cesarean delivery (RR: 0.69, 95% CIs: 0.53-0.91), compared with those who did not.

CONCLUSION

The administration of anesthesia not only significantly reduces maternal pain but also significantly increases the success rate of ECV in women with malpresentation at term, leading to a significant rise in the incidence of vaginal delivery. However, it may increase the incidence of maternal hypotension.

SYSTEMATIC REVIEW REGISTRATION

The protocol was prospectively registered with PROSPERO, registration CRD42022381552.

Systematic review of the effectiveness of remifentanil in term breech pregnancies undergoing external cephalic version

BACKGROUND

External cephalic version (ECV) is a moderately painful procedure used to turn a fetus from a non-vertex to cephalic position. This systematic review and meta-analysis compared intravenous remifentanil with other analgesia or no analgesia or placebo on the success rate and associated pain of ECV.

METHODS

Systematic searches for randomised controlled trials using remifentanil during ECV for non-cephalic term singleton pregnancies were conducted in EMBASE, MEDLINE and Cochrane Library to October 2021. The primary outcomes were successful ECV and maternal pain; secondary outcomes included mode of delivery and adverse effects. The Cochrane Risk of Bias tool was used and meta-analysis undertaken if there were ≥2 comparable studies.

RESULTS

Four trials were identified, three placebo-controlled and one vs no analgesia, totalling 482 participants. Comparisons against nitrous oxide or neuraxial anaesthesia were not analysed. Two studies had a low overall risk of bias, and two had some concern for bias. Remifentanil compared with placebo increased the success of ECV by 43% (risk ratio [RR] 1.43; 95% confidence interval [CI] 1.14 to 1.78). Pain scores (0-10) were lower (mean difference -1.97; 95% CI -2.49 to -1.46) whilst there was no impact on caesarean delivery rate (RR 0.97; 95% CI 0.81 to 1.17). Adverse events were rare, with fetal bradycardia observed less often with remifentanil than placebo.

CONCLUSIONS

Remifentanil increases the procedural success of ECV and reduces pain compared with placebo. Trials were at low risk of bias and contained a sufficient number of participants to have reasonable confidence in this finding.

A Systematic Review and Meta-analysis of Clinical Trials of Neuraxial, Intravenous, and Inhalational Anesthesia for External Cephalic Version

BACKGROUND

External cephalic version (ECV) is a frequently performed obstetric procedure for fetal breech presentation to avoid cesarean delivery. Neuraxial, intravenous, and inhalational anesthetic techniques have been studied to reduce maternal discomfort caused by the forceful manipulation. This study compares the effects of these anesthetic techniques on ECV and incidence of cesarean delivery.

METHODS

We conducted a comprehensive literature search for published randomized controlled trials (RCTs) or well-conducted quasi-randomized trials of ECV performed either without anesthesia or under neuraxial, intravenous, or inhalational anesthesia. Pairwise random-effects meta-analyses and network meta-analyses were performed to compare and rank the perinatal outcomes of the 3 anesthetic interventions and no anesthesia control, including the rate of successful version, cesarean delivery, maternal hypotension, nonreassuring fetal response, and adequacy of maternal pain control/satisfaction.

RESULTS

Eighteen RCTs and 1 quasi-randomized trial involving a total of 2296 term parturients with a noncephalic presenting singleton fetus were included. ECV under neuraxial anesthesia had significantly higher odds of successful fetal version compared to control (odds ratio [OR] = 2.59; 95% confidence interval [CI], 1.88-3.57), compared to intravenous anesthesia (OR = 2.08; 95% CI, 1.36-3.16), and compared to inhalational anesthesia (OR = 2.30; 95% CI, 1.33-4.00). No association was found between anesthesia interventions and rate of cesarean delivery. Neuraxial anesthesia was associated with higher odds of maternal hypotension (OR = 9.33; 95% CI, 3.14-27.68). Intravenous anesthesia was associated with significantly lower odds of nonreassuring fetal response compared to control (OR = 0.36; 95% CI, 0.16-0.82). Patients received neuraxial anesthesia reported significantly lower visual analog scale (VAS) of procedure-related pain (standardized mean difference [SMD] = -1.61; 95% CI, -1.92 to -1.31). The VAS scores of pain were also significantly lower with intravenous (SMD = -1.61; 95% CI, -1.92 to -1.31) and inhalational (SMD = -1.19; 95% CI, -1.58 to -0.8) anesthesia. The VAS of patient satisfaction was significantly higher with intravenous anesthesia (SMD = 1.53; 95% CI, 0.64-2.43).

CONCLUSIONS

Compared to control, ECV with neuraxial anesthesia had a significantly higher successful rate; however, the odds of maternal hypotension increased significantly. All anesthesia interventions provided significant reduction of procedure-related pain. Intravenous anesthesia had significantly higher score in patient satisfaction and lower odds of nonreassuring fetal response. No evidence indicated that anesthesia interventions were associated with significant decrease in the incidence of cesarean delivery compared to control.

Nitrous oxide analgesia for external cephalic version: A randomized controlled trial

STUDY OBJECTIVE

Our study sought to determine whether or not nitrous oxide analgesia decreases pain compared to oxygen placebo during external cephalic version for breech presentation. Procedural success may be limited by pain and anxiety. Although neuraxial anesthesia has been studied extensively for these procedures, many centers lack resources for routine use. Nitrous oxide is noninvasive, has minimal side effects and requires limited facilities. We hypothesized that its analgesic properties would decrease pain compared to oxygen placebo during external cephalic version.

DESIGN

Double-blinded randomized placebo-controlled trial.

SETTING

Labor and delivery triage room.

PATIENTS

Forty-eight patients, ≥18 years of age, 37-weeks' gestation or beyond, singleton pregnancy, breech presentation, and American Society of Anesthesiology physical status I-III, having an external cephalic version.

INTERVENTIONS

Patients undergoing external cephalic version were randomized to receive self-administered 50% nitrous oxide/50% oxygen versus 100% oxygen placebo.

MEASUREMENTS

The primary outcome measured was intra-procedural pain. Secondary outcomes were intra-procedural anxiety, patient satisfaction, and procedure difficulty.

MAIN RESULTS

Forty-eight patients were enrolled; 23 received nitrous oxide and 25 received oxygen. No difference was noted in mean pain scores (nitrous oxide 5.5 ± 2.3, placebo 5.4 ± 2.7, [CI_95% = -1.40, 1.51]; P = 0.943) or anxiety scores (nitrous oxide 1.6 ± 2.0, placebo 1.2 ± 1.8, [CI_95% = -0.74, 1.45]; P = 0.515). Procedural difficulty (1-10 scale, 1 = very easy, 10 = extremely difficult) was not different between groups (nitrous oxide 6.1 ± 2.2, placebo 6.1 ± 3.2, [CI_95% = -1.54, 1.66]; P = 0.944). There was a significant increase in the number of version attempts in the nitrous oxide group (nitrous oxide 3.9 ± 1.9, placebo 2.8 ± 1.4, [CI_95% = 0.05, 2]; P = 0.046). Patient satisfaction was significantly lower in the nitrous oxide group (nitrous oxide 4.3 ± 4.0, placebo 6.9 ± 3.6, [CI_95% = -4.93, -0.34]; P = 0.025).

CONCLUSION

Despite the desirable properties of nitrous oxide, there was no analgesic benefit over oxygen for external cephalic version. Its routine use for these procedures was not supported.

Maternal and perinatal outcomes in external cephalic version: prognostic factors for the success of the technique

Background We aimed to analyze the success rate of external cephalic version (ECV) for breech presentations performed in our center between March 2011 and March 2016. We evaluated factors related to a successful ECV, delivery mode, complications and newborn status after ECV. Methods Analysis of assembled data of 327 consecutive ECVs in the third trimester was done. Results The total success rate was 56.6%. After a successful ECV, 85.9% of the fetuses were delivered vaginally. Logistic regression analysis of background factors leading to a successful ECV showed that tocolysis with ritodrine and anterior placenta were each significantly correlated with the rate of successful version. No severe complications were registered during the ECVs, and all babies had normal Apgar scores at delivery. Conclusion These findings suggest that attempting an ECV in breech presentations, once or even twice, seems to be an appropriate management given that a successful ECV decreases the rate of cesarean section in this group of patients and by doing so, it might also decrease the risk of cesarean sections in future pregnancies.

Patient opinion of analgesia during external cephalic version at term in singleton pregnancy

To assess the opinion and the level of satisfaction of patients concerning analgesia during external cephalic version (ECV), we present the results of a survey of 120 women undergoing ECV at term during a randomised controlled trial (July 2012 to February 2013) comparing remifentanil and nitrous oxide. Overall, 110 (91.7%) women said they would repeat the procedure and 111 (92.5%) that they would recommend it to another pregnant woman, with no significant differences by type of analgesia. The administration and sense of comfort were rated better in the remifentanil group (p < .01). In conclusion, the use of analgesia during ECV is associated with a high rate of willingness among women to repeat the procedure and recommend it to other pregnant women.Impact statementWhat is already known on this subject? ECV is commonly a painful manoeuvre for the woman. This pain triggers maternal reactive abdominal muscle contraction and involuntary abdominal tensing, reducing the likelihood of successful version and causing some women to reject the technique.What do the results of this study add? The use of analgesia during ECV is associated with a high rate of willingness among women to repeat the procedure and recommend it to other pregnant women. The sense of comfort during ECV was also significantly better in the remifentanil group, probably because of its greater analgesic power and greater comfort during its administration.What are the implications of these findings for clinical practice and/or further research? ECV should be carried out under analgesia, when available, not only to decrease pain but also to encourage wider adoption of the technique and enable more women to benefit from it.

Remifentanil analgesia during external cephalic version for breech presentation in nulliparous women at term: A randomized controlled trial

BACKGROUND

The aim of the study was to assess the efficacy and safety of remifentanil for pain relief during external cephalic version (ECV) for breech presentation in nulliparous women at term.

METHODS

A total of 144 nulliparous women with singleton breech presentation were randomly divided into the intervention group and the placebo group, with 72 subjects in each group. The subjects in the intervention group received remifentanil (infused at 0.1 μg kg min with demand boluses of 0.1 μg/kg), whereas those in the placebo group were given saline placebo. This study was conducted from May 2013 to April 2016. The outcomes measures include pain (measured with the visual analog scale, VAS), success rate of ECV, maternal satisfaction for ECV, and adverse events.

RESULTS

A total of 137 participants completed the study. The intervention with remifentanil showed greater efficacy than did placebo in decreasing the VAS score immediately after ECV (intervention group 4.3 ± 2.2 vs placebo group 6.4 ± 2.5, P < 0.01). A significant difference in the ECV success rate was also found between the 2 groups (intervention group 56.9% vs placebo group 38.9%, P = 0.03). In addition, a significant difference in the satisfaction score was also detected (intervention group 9.3 ± 0.9 vs placebo group 6.7 ± 1.2, P < 0.01). The observed adverse events were similar between the 2 groups.

CONCLUSION

This study shows that remifentanil could decrease pain, improve the ECV success rate, and improve satisfaction in nulliparous women at term during the period of ECV. Furthermore, it is also well tolerated with few adverse events.

Obstetric and Anesthetic Approaches to External Cephalic Version

Breech presentation is the most common abnormal fetal presentation and complicates approximately 3% to 4% of all pregnancies. External cephalic version (ECV) should be recommended to women with a breech singleton pregnancy, if there is no maternal or fetal contraindication. ECV increases the chance of cephalic presentation at the onset of labor and decreases the rate of cesarean delivery by almost 40%. The success rate of ECV is approximately 60%. Review of the risks and benefits for performing an ECV and for both the timing of ECV and the number of attempts should be should be discussed with the patient.

A randomized trial of remifentanil for analgesia in external cephalic version for breech presentation

BACKGROUND

Although external cephalic version (ECV) can be effective for correcting the fetus in a cephalic presentation, it may be painful for the mother. This study aimed to evaluate the efficacy and safety of remifentanil for pain relief during ECV in China.

METHODS

In all, 152 Chinese parturients with singleton breech presentation were randomly divided into 2 groups, each with 76 patients. All 152 patients were assigned to receive either remifentanil (infused at 0.1 μg/kg/min and demand boluses of 0.1 μg/kg) or saline placebo. The study was performed between January 2012 and December 2015. Outcome measurements included the Numerical Rating Pain Scale score (0-10) after ECV, success rate for ECV, and maternal satisfaction after ECV. Adverse events were also evaluated.

RESULTS

The study was completed by 146 patients. Remifentanil showed greater efficacy than placebo in decreasing the pain score immediately after ECV (remifentanil 4.6 ± 2.6 vs placebo 6.5 ± 2.7; P < 0.001). The success rate for ECV showed a significant difference between the 2 groups (remifentanil 56.5% vs placebo 39.5%; P = 0.04). Maternal satisfaction also showed a significant difference between the 2 groups (remifentanil 9.6 ± 1.4 vs placebo 6.4 ± 3.7; P < 0.001). However, the adverse events profiles were similar between both groups.

CONCLUSION

The results of this study demonstrate that remifentanil is an effective intervention for reducing pain, achieving successful ECV, and increasing maternal satisfaction during ECV, and is generally well-tolerated without additional adverse effects.

Interventions for helping to turn term breech babies to head first presentation when using external cephalic version

BACKGROUND

Breech presentation is associated with increased complications. Turning a breech baby to head first presentation using external cephalic version (ECV) attempts to reduce the chances of breech presentation at birth so as to avoid the adverse effects of breech vaginal birth or caesarean section. Interventions such as tocolytic drugs and other methods have been used in an attempt to facilitate ECV.

OBJECTIVES

To assess, from the best evidence available, the effects of interventions such as tocolysis, acoustic stimulation for midline spine position, regional analgesia (epidural or spinal), transabdominal amnioinfusion, systemic opioids and hypnosis, or the use of abdominal lubricants, on ECV at term for successful version, presentation at birth, method of birth and perinatal and maternal morbidity and mortality.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (30 September 2014) and the reference lists of identified studies.

SELECTION CRITERIA

Randomised and quasi-randomised trials comparing the above interventions with no intervention or other methods to facilitate ECV at term.

DATA COLLECTION AND ANALYSIS

We assessed eligibility and trial quality. Two review authors independently assessed for inclusion all potential studies identified as a result of the search strategy and independently extracted the data using a specially designed data extraction form.

MAIN RESULTS

We included 28 studies, providing data on 2786 women. We used the random-effects model for pooling data because of clinical heterogeneity between studies. A number of trial reports gave insufficient information to allow clear assessment of risk of bias. We used GradePro software to carry out formal assessments of quality of the evidence for beta stimulants versus placebo and regional analgesia with tocolysis versus tocolysis alone.Tocolytic parenteral beta stimulants were effective in increasing cephalic presentations in labour (average risk ratio (RR) 1.68, 95% confidence interval (CI) 1.14 to 2.48, five studies, 459 women, low-quality evidence) and in reducing the number of caesarean sections (average RR 0.77, 95% CI 0.67 to 0.88, six studies, 742 women, moderate-quality evidence). Failure to achieve a cephalic vaginal birth was less likely for women receiving a parenteral beta stimulant (average RR 0.75, 95% CI 0.60 to 0.92, four studies, 399 women, moderate-quality evidence). No clear differences in fetal bradycardias were identified, although this was reported for only one study, which was underpowered for assessing this outcome. Failed external cephalic version was reported in nine studies (900 women), and women receiving parenteral beta stimulants were less likely to have failure compared with controls (average RR 0.70, 95% CI 0.60 to 0.82, moderate-quality evidence). Perinatal mortality and serious morbidity were not reported. Sensitivity analysis by study quality was consistent with overall findings.For other classes of tocolytic drugs (calcium channel blockers and nitric oxide donors), evidence was insufficient to permit conclusions; outcomes were reported for only one or two studies, which were underpowered to demonstrate differences between treatment and control groups. Little evidence was found regarding adverse effects, although nitric oxide donors were associated with increased risk of headache. Data comparing different tocolytic drugs were insufficient.Regional analgesia in combination with a tocolytic was more effective than the tocolytic alone for increasing successful versions (assessed by the rate of failed ECVs; average RR 0.61, 95% CI 0.43 to 0.86, five studies, 409 women, moderate-quality evidence), and no difference was identified in cephalic presentation in labour (average RR 1.63, 95% CI 0.75 to 3.53, three studies, 279 women, very low-quality evidence), caesarean sections (average RR 0.74, 95% CI 0.40 to 1.37, three studies, 279 women, very low-quality evidence) nor fetal bradycardia (average RR 1.48, 95% CI 0.62 to 3.57, two studies, 210 women, low-quality evidence), although studies were underpowered for assessing these outcomes. Studies did not report on failure to achieve a cephalic vaginal birth (breech vaginal deliveries plus caesarean sections) nor on perinatal mortality or serious infant morbidity.Data were insufficient on the use of regional analgesia without tocolysis, vibroacoustic stimulation, amnioinfusion, systemic opioids and hypnosis, and on the use of talcum powder or gel to assist external cephalic version, to permit conclusions about their effectiveness and safety.

AUTHORS' CONCLUSIONS

Parenteral beta stimulants were effective in facilitating successful ECV, increasing cephalic presentation in labour and reducing the caesarean section rate, but data on adverse effects were insufficient. Data on calcium channel blockers and nitric acid donors were insufficient to provide good evidence.The scope for further research is clear. Possible benefits of tocolysis in reducing the force required for successful version and possible risks of side effects need to be addressed further. Further trials are needed to compare the effectiveness of routine versus selective use of tocolysis and the role of regional analgesia, fetal acoustic stimulation, amnioinfusion and abdominal lubricants, and the effects of hypnosis, in facilitating ECV. Although randomised trials of nitric oxide donors are small, the results are sufficiently negative to discourage further trials. Intervention fidelity for ECV can be enhanced by standardisation of the techniques and processes used for clinical manipulation of the fetus in the abdominal cavity and ought to be the subject of further research.