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Re: external cephalic versionFrom: Efrain Ramirez (eramirez@icepr.com)Sun Apr 30 12:16:46 2000
"What are the success rates for external cephalic version, and what factors are predictive of either success or failure? A review of 20 studies indicates that success rates for ECV range from 35% to 86%, with an average success rate of 58% (4, 6, 9, 12–14, 16–18, 21–25, 27, 29–31). Most authors report a positive association between parity and successful version (4, 6, 13, 21–25, 30, 31). A transverse or oblique lie is associated with higher immediate success rates (13, 29, 30). Opinion is divided about the predictiveness of other factors, including amniotic fluid volume, location of placenta, and maternal weight. Some reports indicate an association between normal or increased amounts of amniotic fluid and successful ECV (12, 13, 24, 32), whereas other reports do not (20). Two authors reported an association between successful ECV and placenta location (20, 24), whereas others failed to find an association (12, 13, 29). Two authors found obesity to be associated with a higher failure rate (23, 30), whereas others found maternal weight not to be a significant predictor of success (12, 13, 19, 20). Although scoring systems have been developed to predict which candidates will have a successful version attempt, these have not been validated by multiple studies. One system considered parity, dilatation, estimated fetal weight, placenta location, and station. Nulliparity, advanced dilatation, fetal weight of less than 2,500 g, anterior placenta, and low station were less likely to be associated with success (20). Such variables may provide useful clinical information for obtaining informed consent from individuals for ECV; no single system, however, has been shown to have complete accuracy. How does the use of tocolysis affect the success rate of external cephalic version? Two of six randomized controlled trials failed to find a significant advantage in using tocolytics during ECV attempts (19, 27). One third reported significantly greater success associated with hexoprenaline but not with ritodrine (33). An additional randomized study reported an initial advantage associated with the use of ritodrine, specifically among nulliparous women. However, as the physicians became proficient at the ECV technique, the advantage diminished (34). The largest randomized study using a ritodrine infusion found significant improvement only among nulliparous patients (35). Finally, a randomized study of terbutaline found the success rate of version associated with use of this tocolytic to be almost double the rate without its use (36). In the vast majority of published studies, a tocolytic agent was used routinely (6, 11–18, 20–23, 27–29, 37). Several studies used tocolytics selectively (5, 7, 9, 34), and some used no tocolytic agents (4, 25). Existing evidence may support the use of a tocolytic agent during ECV attempts, particularly in nulliparous patients. How does the use of anesthesia affect the success rate of external cephalic version? A randomized study found a significantly greater success rate associated with the use of epidural anesthesia, although the success rate was unusually low for the women who did not receive epidural anesthesia (32%) (38). Two studies reported results for women in whom ECV was performed while using epidural anesthesia (10, 15). In one study, use of epidural anesthesia was associated with a significantly greater success rate compared with no use of epidural anesthesia (15). However, the procedure was administered selectively to patients according to physician preference, raising the potential for selection bias. The other study merely noted that ECV was performed without difficulty on three women undergoing epidural anesthesia (10). It also has been suggested that epidural anesthesia be considered for women who failed a previous version attempt (39). Another randomized trial addressed the use of spinal anesthesia before the version attempt and found no significant difference between treatment groups (40). Currently, there is not enough consistent evidence to make a recommendation favoring spinal or epidural anesthesia during ECV attempts. Summary The following recommendation is based on good and consistent scientific evidence (Level A): Because the risk of an adverse event occurring as a result of ECV is small and the cesarean delivery rate is significantly lower among women who have undergone successful version, all women near term with breech presentations should be offered a version attempt. The following recommendations are based on limited or inconsistent scientific evidence (Level B): Patients should have completed 36 weeks of gestation before attempting ECV. Previous cesarean delivery is not associated with a lower rate of success; however, the magnitude of the risk of uterine rupture is not known. There is insufficient evidence to recommend routine tocolysis for ECV attempts for all patients, but it may particularly benefit nulliparous patients. Evidence is inconsistent regarding the benefits of anesthesia use during ECV attempts. Cost-effectiveness depends upon utilization of vaginal breech deliveries and costs of the version protocol at a particular institution, but at least one decision analysis suggests the policy is cost effective. The following recommendations are based primarily on consensus and expert opinion (Level C): Fetal assessment before and after the procedure is recommended. External cephalic version should be attempted only in settings in which cesarean delivery services are readily available."
At Sat, 29 Apr 2000, Steve & Eryl Raymond wrote:
>
>As a result of reading this our policy has been established as
-- "The things you learn after you know everything are the important ones"
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