Reply

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Daniel L. Clarke-Pearson, MD Division of Gynecologic Oncology Department of Obstetrics and Gynecology and Lineberger Clinical Cancer Center University of North Carolina

Chapel Hill, NC

Dr Barber is supported by National Institutes of Health 5T32 HD040672-15. The authors report no conﬂict of interest.

REFERENCES

1.Gould MK, Garcia DA, Wren SM, et al. Prevention of VTE in nonorthopedic surgical patients: antithrombotic therapy and prevention

of thrombosis, 9th ed: American College of Chest Physicians evidence-based clinical practice guidelines. Chest 2012;141(Suppl). e227-77S.

2.Caprini JA. Thrombosis risk assessment as a guide to quality patient care. Dis Mon 2005;51:70-8.

3.Stroud W, Whitworth JM, Miklic M, et al. Validation of a venous thromboembolism risk assessment model in gynecologic oncology. Gynecol Oncol 2014;134:160-3.

4. Barber EL, Clarke-Pearson DL. The limited utility of currently avaiable venous thromboembolism risk assessment tools in gyne-cological oncology patients. Am J Obstet Gynecol. epub 2016 Apr 27.

Neuraxial blockade increases external cephalic

version success: a well-known finding needing

to be disseminated within the obstetric domain

TO THE EDITORS: We read the recent meta-analysis by Magro-Malosso et al1 with interest and agree with their findings confirming improved success rates of external ce-phalic version (ECV) with neuraxial blockade. We were sur-prised, however, that the authors stated that no such previous meta-analysis exists, since efficacy of neuraxial block for ECV was first described in 2010. A previous meta-analysis2 and systematic review3 both have reported improved ECV success rates with the use of neuraxial blockade. We find it concerning that published literature in anesthesia journals have not been disseminated within the obstetric domain and that this omission was not detected during the peer-review process. We are nevertheless hopeful that this publication will lead to greater obstetrical awareness and use of this tech-nique, which can improve ECV success, and importantly potentially avoid a cesarean delivery for women with breech presentation.

We agree with the authors that the optimal neuraxial technique and dose required to maximize ECV success have yet to be elucidated; however, they fail to cite a key subgroup analysis from a previous meta-analysis clearly demonstrating that anesthetic rather than analgesic dosing strategies are needed to optimize success rates.2 Muscle relaxation from anesthesia is therefore likely to be required, and analgesia alone probably is inadequate to facilitate ECV.

Concerns have been raised regarding the potential for morbidity secondary to the use of greater force by the obstetrician in the presence of less maternal pain and abdominal muscle contraction under anesthesia. The authors do address the safety aspect of performing ECV under neu-raxial block; however, they do not refer to systematic review safety data previously extrapolated from a larger cohort of patients (n ¼ 850) including both randomized and non-randomized controlled studies.3 The incidence of placental

abruption was found previously to be 0.22% (95% conﬁdence interval [95% CI], 0.07e0.66%) with neuraxial block compared with 0.48% (95% CI. 0.16e1.44%) in control groups, and requirement for emergency cesarean delivery for nonreassuring heart rate was 0.44% (95% CI, 0.15e1.32) with neuraxial block compared to 0.48% (95% CI, 0.16e1.44) in control groups.3

In summary, we thank Magro-Malosso et al for high-lighting the role of neuraxial blockade in improving the success rates of ECV. The omission of key publications in their meta-analysis highlights inadequate dissemination of anesthesia ﬁndings within the obstetric specialty. We hope interspecialty transfer of such information will occur in the future. Importantly, providers using neuraxial anesthesia to facilitate ECV should use anesthetic doses to optimize the

success of ECV.

-Pervez Sultan

Department of Anaesthesia University College London Hospital London, United Kingdom

p.sultan@doctors.org.uk

Carolyn F. Weiniger

Hadassah Hebrew University Medical Center Jerusalem, Israel

Brendon Carvalho

Stanford University School of Medicine

P.S. has received research capability funding from the National Institute for Health Research (reference RCF146/PS/2014).

REFERENCES

1.Magro-Malosso ER, Saccone G, Di Tommaso M, Mele M, Berghella V. Neuraxial analgesia to increase the success rate of external cephalic version: a systematic review and metaanalysis of randomized controlled trials. Am J Obstet Gynecol 2016;215:276-86.

NOVEMBER 2016 American Journal of Obstetrics_{& Gynecology} 675

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2.Lavoie A, Guay J. Anesthetic dose neuraxial blockade increases the success rate of external fetal version: a meta-analysis. Can J Anaesth 2010;57:408-14.

3.Sultan P, Carvalho B. Neuraxial blockade for external cephalic version: a systematic review. Int J Obstet Anesth 2011;20:299-306.

REPLY

Thank you for your letter and your interest. We are aware of the existence of previous meta-analyses about this topic, but the fact that there were a few and we had limited editorial space restricted our opportunity to review them in detail, except for the Cochrane, which we mentioned in our article. We did not state that such meta-analyses do not exist but“To our knowledge, no prior meta-analysis on this issue is as large, up to date or comprehensive.” Moreover, we are very aware of the anesthesia literature (3 of our references were indeed from anesthesia journals),1-3 and one of our co-authors is an anesthesiologist.

The ﬁrst meta-analysis on maternal anesthesia as inter-vention to facilitate external cephalic version (ECV) was published in 2004, with 4 randomized controlled trials (RCTs) included.4 A second meta-analysis was published in 2010 with 7 RCTs included.5Another meta-analysis published in 2011 included 6 RCTs, excluding abstracts.6Drs Sultan and Carvalho’s (authors of this letter) meta-analysis included 6 RCTs.7Our meta-analysis includes 9 RCTs.8

We recognize the excellent work in the meta-analysis by Lavoie and Guay,4 and we agree that optimizing muscle relaxation in addition to maternal comfort increases the success rate of ECV. We chose not to include a subgroup analysis of anesthetic dose vs analgesic dose because this was a very heterogeneous group with varying medication types and doses. We believe these different neuraxial tech-niques have inherent differences in the quality of muscle relaxation, with a spinal technique possibly producing more relaxation of the anterior abdominal wall than that pro-duced by epidural despite the same sensory level. The levels documented in the studies included in our meta-analysis were based on assessing sensory level only and excluded simple motor testing. We believe this represents an op-portunity in the future to compare muscle relaxation in spinal versus epidural to differentiate the effectiveness of these neuraxial techniques in facilitating ECV.

We thank Drs. Sultan and Carvalho, as they also point to the safety of ECV under neuraxial anesthesia, citing their randomized and nonrandomized data.7In our meta-analysis of RCTs only, we reported on several more safety outcomes than Sultan and Carvalho, including emergency cesarean delivery, transient fetal bradycardia, nonreassuring fetal testing (excluding transient bradycardia) after ECV, and abruption placentae, which were all similar between ECV

with or without neuraxial analgesia, whereas a signiﬁcantly lower incidence of maternal discomfort and a lower pain score were found with neuraxial analgesia.8

In summary, we want to thank the authors for this letter because it gives us the opportunity to clarify some as-pects of our meta-analysis and to highlight again the safety and efﬁcacy of neuraxial analgesia in improving ECV

success.

-Elena Rita Magro-Malosso, MD Department of Health Science

Division of Pediatrics, Obstetrics and Gynecology Careggi Hospital University of Florence

Florence, Italy Michele Mele, MD

Department of Anesthesiology

Sidney Kimmel Medical College of Thomas Jefferson University Philadelphia, PA

Gabriele Saccone

Department of Neuroscience, Reproductive Sciences and Dentistry School of Medicine

University of Naples Federico II Naples, Italy

Vincenzo Berghella, MD

Division of Maternal-Fetal Medicine Department of Obstetrics and Gynecology

Sidney Kimmel Medical College of Thomas Jefferson University Philadelphia, PA

vincenzo.berghella@jefferson.edu

REFERENCES

1.Sullivan JT, Grobman WA, Bauuchat JR, et al. A randomized controlled trial of the effect of combined spinal-epidural analgesia on the success of external cephalic version for breech presentation. Int J Obstet Anesth 2009;18:328-34.

2.Weiniger CF, Ginosar Y, Elchalal U, Sela HY, Weissman C, Ezra Y. Randomized controlled trial of external cephalic version in term multiparae with or without spinal analgesia. Br J Anaesth 2010;104:613-8. 3.Khaw KS, Lee SW, Ngan Kee WD, et al. Randomized trial of anaes-thetic interventions in external cephalic version for breech presentation. Br J Anaesth 2015;114:944-50.

4.Lavoie A, Guay J. Anesthetic dose neuraxial blockade increases the success rate of external fetal version: a meta-analysis. Can J Anaesth 2010;57:408-14.

5.Macarthur AJ, Gagnon S, Tureanu LM, Downey KN. Anesthesia facilitation of external cephalic version: a meta-analysis. Am J Obstet Gynecol 2004;191:1219-24.

6.Goetzinger KR, Harper LM, Tuuli MG, Macones GA, Colditz GA. Effect of regional anesthesia on the success rate of external cephalic version: a systematic review and meta-analysis. Obstet Gynecol 2011;118: 1137-44.

7.Sultan P, Carvalho B. Neuraxial blockade for external cephalic version: a systematic review. Int J Obstet Anesth 2011;20:299-306.

8. Magro-Malosso ER, Saccone G, Di Tommaso M, Mele M, Berghella V. Neuraxial analgesia to increase the success rate of external cephalic version: a systematic review and meta-analysis of randomized controlled trials. Am J Obstet Gynecol 2016 [Epub ahead of print].

676 American Journal of Obstetrics & Gynecology NOVEMBER 2016