Anesth Analg 2001;93:410-413
© 2001 International Anesthesia Research Society
OBSTETRIC ANESTHESIA
The Effect of Intrathecal Analgesia on the Success of External Cephalic Version
David J. Birnbach, MD,
Jay Matut, MD,
Deborah J. Stein, MD,
Joanne Campagnuolo, DO,
Calin Drimbarean, MD,
Amos Grunebaum, MD,
Maxine M. Kuroda, PhD, MPH, and
Daniel M. Thys, MD
Departments of Anesthesiology and Obstetrics and Gynecology, St. Luke’s-Roosevelt Hospital Center, College of Physicians and Surgeons of Columbia University, New York, New York
Address correspondence to David J. Birnbach, MD, Director of Obstetric Anesthesiology, St. Luke’s-Roosevelt Hospital Center, 1000 Tenth Avenue, New York, NY 10019. Address e-mail to djb2{at}columbia.edu
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Abstract
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External cephalic version (ECV), the procedure whereby a fetus in the breech position is converted to vertex, is often performed to avoid an operative delivery. Potential benefits of epidural and spinal anesthesia for this procedure are controversial. Several previous studies have evaluated the use of epidural anesthesia with varying results. We sought to determine whether analgesia produced by subarachnoid sufentanil would safely improve the success of ECV. Patients who received subarachnoid analgesia (n = 20) were compared with those who did not (n = 15) in regard to success of ECV, level of pain during ECV, and satisfaction. ECV was successful in 21 patients (60%), with more frequent success in women who received spinal analgesia as compared with those who did not (80% vs 33%, respectively; P = 0.005). Patients who received spinals also reported smaller pain scores and were more satisfied with ECV. None of the women who received spinal analgesia developed a postdural puncture headache, and the only case of fetal bradycardia occurred in a patient who did not receive spinal analgesia. More profound patient comfort after spinal analgesia may have permitted greater manipulation of the abdomen during ECV, thus improving success rates of ECV without increasing risk.
IMPLICATIONS: The success of external cephalic version (ECV) was compared in women who received spinal analgesia and those who did not. Successful ECV occurred more frequently in those women who received spinal analgesia. Because term singleton pregnancies associated with breech position usually require cesarean delivery, an increase in success of ECV may decrease the number of cesarean deliveries performed.
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Introduction
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Approximately 4% of term singleton pregnancies are associated with breech position, usually requiring delivery by cesarean section (1). External cephalic version (ECV) may be performed in an effort to convert the fetus from breech to vertex presentation and thus avoid an operative delivery. Success rates for ECV, however, have been variable, ranging from 35%–86%, with an average rate of 58% (2). Although previously reported trials demonstrated that dense epidural anesthesia improves the success rate of ECV (2–4), Neiger et al. (5) have suggested that neuraxial techniques should be discouraged for ECV because solid anesthesia might allow for the application of too much force that might in turn cause injury to the fetus or to the uterus. However, there have been no reports of uterine rupture during attempted ECV under neuraxial analgesia and the appropriate amount of force for safe version has not been quantified. Rawal et al. (6) in a review of the combined spinal-epidural technique, have reported that subarachnoid administration of opioids with or without small doses of local anesthetics provides analgesia without the dense motor block associated with older epidural techniques. If subarachnoid opioids were administered for ECV, the mother would experience less pain but would possibly be more able to feel excessive force, express this to her obstetrician, and thus reduce the potential risks. This study was designed to determine whether analgesia produced by subarachnoid sufentanil would safely improve the success of ECV at term.
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Methods
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After IRB approval and written informed consent, all patients at >36 wk gestation who were candidates for ECV were offered subarachnoid analgesia for the procedure. All patients were healthy and at least 18 yr of age with singleton pregnancies in the breech position with intact membranes and estimated fetal weight between 2000 and 4000 g. Patients were excluded if they had a nonreassuring fetal heart rate tracing, placenta previa, previous ECV or cesarean delivery, or amniotic fluid index of <5. No patient was in active labor at the time of the study, and all patients were given 0.25 mg subcutaneous terbutaline approximately 20 min before the start of the ECV. Patients who gave consent for subarachnoid analgesia were given 500 mL of lactated Ringer’s solution IV, and 10 µg of intrathecal sufentanil via a 26-gauge Gertie Marx ("atraumatic") spinal needle inserted at the L3-4 interspace with the patient in the sitting position. Proper functioning of the spinal opioid was verified by loss of sensation to pinprick to at least the T10 level. All patients were monitored for 30 min after the intrathecal injection and remained on the labor and delivery suite for at least 2 h after the procedure. Patients who declined subarachnoid analgesia were offered analgesia with 50 mg IV meperidine, as per obstetric protocol. Patients who underwent ECV without spinal analgesia served as the No-Spinal Control group.
Real-time ultrasonography was performed to confirm breech position of the fetus and to estimate fetal weight and amniotic fluid index before study enrollment. ECV was performed under ultrasound guidance in the labor and delivery suite with continuous electronic fetal heart rate monitoring and cesarean delivery facilities immediately available. ECV was performed by one of three obstetricians who had similar success rates for ECV and were not informed of patient group. Each obstetrician made no more than five attempts at ECV.
Demographic data included maternal age, height, weight, parity, and gestational age and estimated weight of the fetus. As soon as the ECV procedure, successful or not, was completed, each patient was asked to rate her level of pain during the ECV on a visual analog scale on which 0 = no pain and 10 = worst possible pain. In addition, each patient was asked to rate how satisfied she was with the procedure on a scale on which 0 = completely dissatisfied and 10 = completely satisfied.
As a check on whether the success rate of ECV in the No-Spinal Control group might be affected by self-selection factors, we reviewed the results of all ECV procedures (n = 58) that had been performed in the preceding 2 yr, when no patient received neuraxial analgesia for ECV at this institution. These 58 subjects constituted a historical control group.
A power analysis estimated that 16 patients in each group would be sufficient to detect a difference of 0.5 in successful ECV rate between the Spinal and No-Spinal groups at 
= 0.05 and power = 0.80.
Data are presented as mean ± SD for continuous variables or as number (%) for discrete variables. Variables with nonnormal distributions are presented as median (25th, 75th percentiles). Differences between continuous variables were tested by Student’s t-tests; associations among the categories of discrete variables were tested by 
2 or Fisher’s exact tests, as appropriate. The Mann-Whitney U-test was used to evaluate differences between the groups on variables that had nonnormal distributions (e.g., visual analog scale pain scores). P values 
0.05 were considered statistically significant. All analyses were performed with the Statistical Package for the Social Sciences (SPSS Version 5.02 for Windows; SPSS, Chicago, IL).
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Results
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During the study period, 35 patients were candidates for ECV. Twenty of these patients opted to receive subarachnoid analgesia and were compared with the 15 patients who opted against spinal analgesia. The two groups did not differ with regard to maternal age and height. Patients in the Spinal group were, on average, heavier than patients in the No-Spinal group; however, there was no difference in body mass index between the two groups (Table 1). The groups also did not differ in their pregnancy characteristics, including parity, gestational age, estimated fetal weight, and amniotic fluid index (Table 1). Although offered, no patient in either group received parenteral opioids.
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Table 1. Demographic Characteristics of 35 Patients who Underwent External Cephalic Version (ECV) With or Without Spinal Analgesia
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Overall, ECV was successful in 21 patients (60%). The proportion with successful ECV was similar for nulliparous and multiparous patients (43% and 57%, respectively; P > 0.05). There were no significant differences in success rates among the three obstetricians. Successful ECV was not associated with the other maternal or fetal characteristics measured, including maternal weight.
The proportion of women with successful ECV was larger in those who received spinal analgesia than in those who did not (80% vs 33%, respectively, P = 0.005). The time taken to achieve successful ECV or the total time that ECV was attempted before being discontinued on patients with unsuccessful ECV did not differ between the Spinal and No-Spinal groups (Table 2).
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Table 2. Characteristics Among 35 Patients who Underwent External Cephalic Version (ECV) With or Without Spinal Analgesia
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For both groups, the median number of attempts at ECV was two and the maximum was five. As successful ECV would terminate further attempts, the likelihood of successful ECV was evaluated in a logistic regression model that controlled for number of attempts. Patients who had ECV under spinal analgesia were much more likely to have a successful result than were patients who did not receive spinal analgesia (adjusted OR = 39, P = 0.02).
There were no differences between Historical Controls and the Spinal group with regard to age, height, weight, parity, and amniotic fluid index. Among the 58 Historical controls, ECV was successful in 26 (45%). Although this success rate was somewhat higher than that of the No-Spinal controls in this study (33%), the difference was not significant (P = 0.6, Fisher’s exact test).
Compared with those who did not receive spinal analgesia, patients who received spinals reported smaller pain scores and were more satisfied with the ECV (Table 2). Successful ECV was also associated with patient satisfaction. Although all of the 21 patients who had successful ECV reported that they were very satisfied with the procedure (score 
8), only 2 of the 14 patients (14%) whose ECV failed reported this level of satisfaction (P << 0.0001).
No patient in the Spinal Analgesia group developed a postdural puncture headache. There was a single case of fetal bradycardia that required an emergency cesarean delivery in a patient who did not receive spinal analgesia. Forty percent of the patients in the Spinal group acknowledged pruritus. All cases of pruritus resolved within 20 min without pharmacologic intervention. There were no cases of uterine rupture.
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Discussion
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Spinal analgesia, as has been previously reported for epidural anesthesia, increased the success rate of ECV as practiced at this institution. Because of the rarity of adverse events after ECV, this study was underpowered to answer questions about potential risks of ECV under spinal analgesia, including fetal bradycardia and uterine rupture. However, none of the risks thought to be associated with this technique were seen in the group that received spinal analgesia for ECV. For instance, depending on the spinal needle used, spinal techniques may be associated with postdural puncture headache (7). In this study, however, atraumatic spinal needles were used and no patient developed postdural puncture headache. The most common complication of ECV is fetal bradycardia (8), which is associated with the administration of spinal opioids for labor analgesia (9). There is controversy, however, as to whether bradycardia actually occurs after the administration of spinal opiates in the parturient (10) and whether the bradycardia associated with ECV is clinically significant (11). In this study, the single case of abnormal fetal heart rate tracing occurred in the No-Spinal group.
Although the safety, efficacy, and cost-effectiveness of ECV have been demonstrated by several authors (12,13), complications do occur (8,14), and the use of neuraxial anesthesia for this procedure remains controversial. Although previous studies found that epidural anesthesia improved the success of ECV (3–5), one study also found that epidural anesthesia improved the success rate in patients who had failed ECV without anesthesia (5).
The only previous study evaluating a spinal technique for ECV found no difference in ECV success (15). That study randomized patients and blinded the obstetricians to randomization sequence but not patient group. A limitation of our study is that blinding was not possible. Although originally designed to be a randomized controlled study, this was not possible because it was evident that the obstetricians could tell which patients had been given spinal analgesia and which had not. Because of this inability to blind the investigators, we decided that all patients would receive a thorough explanation of the risks and benefits of spinal analgesia for ECV and that patients who did not want spinal analgesia would be treated as No-Spinal controls and given parenteral opioids if pain relief was necessary. Although we did not tell our obstetricians whether the patient had received spinal analgesia, it was usually obvious. Our inability to blind the obstetricians appears to be associated with several factors necessary for successful ECV, e.g., the patient’s expression of pain during the procedure and the obstetrician’s willingness to proceed with the ECV despite that pain. However, the comparison with our historical controls revealed no factors that may have contributed to self-selection of patients into the Spinal Analgesia group. The obstetric practice might determine the effect of spinal analgesia in success of ECV. For example, if the obstetrician is already applying maximal pressure, analgesia might be less effective than if the obstetrician ceases attempts at the first patient complaint of discomfort. This might explain the differences in findings between this study and that of Dugoff et al. (15).
As expected, patient satisfaction was related not only to anesthesia technique but also to success of the procedure. Patient satisfaction was more frequent among patients who had successful outcomes, regardless of analgesia group. If ECV was successful, all patients were satisfied. However, if ECV was unsuccessful, patients who received spinal analgesia reported higher satisfaction scores than those who did not.
Although it is possible that the spinal drug improves success of ECV as a result of better abdominal relaxation, patient comfort does appear to be an important factor. Patient complaints of discomfort may cause the obstetrician to cease further attempts at ECV for fear of applying too much force to the abdomen. The patients in this study who received spinal analgesia were much more comfortable than those who did not, and this may have permitted greater manipulation of the abdomen during ECV. Although force excessive enough to cause direct fetal or maternal trauma should not be used, small increases in force may improve success rates of ECV without increasing risk. Considering the current practice of using smaller doses of sufentanil for labor analgesia, it is possible that similar results with a decreased potential for side effects could have been achieved with the administration of 5 mcg of sufentanil, with or without a small dose of bupivacaine (16).
In conclusion, ECV success rates were increased at our institution after administration of spinal analgesia. Because obstetrician factors, including methods of ECV, and patient populations may vary among institutions, our findings may not be generalizable to other institutions where obstetric practice and the composition of patient population may differ considerably from ours. Although maternal satisfaction and success of ECV are improved after administration of neuraxial analgesia, questions regarding the incidence of rare complications of ECV with or without neuraxial analgesia remain unresolved and suggest the need for a large randomized investigation.
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Footnotes
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Presented, in part, at the annual meeting of the Society for Obstetric Anesthesia and Perinatology, Denver, Colorado, May, 1999.
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References
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Accepted for publication April 3, 2001.
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Abstract
Introduction
