- Email: [email protected]
Trials of Vacuum Extraction
Letters to the Editor—Correspondence / European Journal of Obstetrics & Gynecology and Reproductive Biology 203 (2016) 331–333
332
grant to conduct a randomized control trial exploring whether trans-venous occlusion of pelvic vein incompetence improves symptoms and quality of life in women with PVI and chronic pelvic pain. The results of this study are due to be published in 2018 [1]. We hope that completion of this trial and our case control study will make a significant contribution to the epidemiology of PVI, its role in chronic pelvic pain, and to its subsequent management. Reference [1] Trans-venous occlusion of pelvic vein incompetence. ISRCTN Registry. BioMed Central. http://dx.doi.org/10.1186/ISRCTN15091500 [accessed http://www. isrctn.com/ISRCTN15091500].
diagnostic rigor to consider factors that have been known for a long time to be associated with risk of failure (i.e. any head above the brim of the pelvis at the commencement of the AVD). In our study it was seen that the risk of failure in ‘trials of vacuum extraction’ (59 cases) was 20% and the overall risk of failure for vacuum extraction procedures that were not set up as a trial (689 cases) was 1.8%. Lastly, when there is an obstetric factor that the vacuum extractor is able to correct (most notably deflexon and posterior position), then the odds ratios (OR) for failure should be <1. If this is not the case then the operators are not placing the cup over the flexion point either because they not using posterior cups (or omnicups) or their technique is faulty. Yours sincerely
V. Hansrani D.M. Riding Charles McCollum* Academic Surgery Unit, Institute of Cardiovascular Sciences, 2nd Floor, Education and Research Centre, University Hospital of South Manchester, Manchester, UK
Glen Mola School of Medicine and Health Sciences, UPNG, Papua New Guinea
10 March 2016 *Corresponding author E-mail address: [email protected] (C. McCollum).
http://dx.doi.org/10.1016/j.ejogrb.2016.05.021
http://dx.doi.org/10.1016/j.ejogrb.2016.04.017
Trials of Vacuum Extraction
Authors’ response: Re. Predictors for failure of vacuum-assisted vaginal delivery: a case-control study
Dear Editors,
Dear Editors,
I refer to the article in the European Journal of Obstetrics and Gynecology and Reproductive Biology, May 2016, Volume 200, Pages 29–34, ‘Predictors for failure of vacuum-assisted vaginal delivery: a case–control study’ by Corine J.M. Verhoeven, Chelly Nuij, Christel R.M. Janssen Rolf, Ewoud Schuit, Joke M.J. Bais, S. Guid Oei, Ben Willem J. Mol. We did a study on predictors of failure in ‘Trials of Vacuum Extraction’’ (Mola GDL, Amoa AB, Edilyong J, Factors associated with success or failure in trials of vacuum extraction, Aust NZ J Obstet Gynecol, 2002, Vol. 42, 41–45). I see that in the Dutch study all attempts at vacuum extraction were considered a ‘trial’. I suppose this is true in some ways that any attempt at any procedure may fail, but traditionally ‘a trial of assisted delivery’ has been a very particular clinical scenario where the operator considers that there is a significant risk of failure, and the procedure is usually therefore carried out with set up for immediate recourse to a secondary delivery method (CS or symphysiotomy) should failure occur. It is particularly important when one is conducting AVD in poorly resourced settings (e.g. most developing countries in the world) where recourse to the backup delivery option may take several hours to organize. Under these circumstances a failed AVD (when there was no set up for ‘‘A Trial’’) is considered an ‘unexpected failure’. Unexpected failures in less resourced settings are to be avoided at much as possible as a delay in delivering the fetus of several hours after a failed AVD always leads to poorer fetal outcomes. Perhaps it is the ability in the developed world of being able to perform a CS within a few minutes (whether the failed AVD was ‘unexpected’ or not) and the very much increased risk of failure when the woman has had an epidural, that has led to loss of clinical
We thank professor Mola for his interest in our study and his comments. Professor Mola questions the definition of ‘a trial of assisted delivery’ as we used in our study. In his study he considers a trial of assisted delivery as an attempt of vacuum assisted delivery with a significant risk of failure, whereby the procedure usually is carried out in the operating theatre [1]. In our study we considered all attempts at vacuum extraction a ‘trial’. We agree with professor Mola that any attempt at any procedure may fail. Indeed, this was what we tried to predict. We feel that assessing all attempted vacuum assisted deliveries is the best approach here. In our study, a posterior position was a significant risk factor for failed vacuum-assisted delivery with an adjusted odds ratio of 3.0 (95% CI 2.0–4.6). While professor Mola may argue that this position can be corrected, we show that deflexion and occiput posterior (OP) position increases the risk of failure. We challenge professor Mola to present data on a series of patients where he turns the baby form OP position to OA position while keeping the risk of failure low. Our study shows that failed vacuum assisted delivery can be predicted. However, there is a strong need for validation of our model in a prospective observational study. We hope that this answer will help in using the data that we supplied. On behalf of the authors,
DOI of original article: http://dx.doi.org/10.1016/j.ejogrb.2016.05.021 Original article: ‘‘Predictors for failure of vacuum-assisted vaginal delivery: a case-control study’’, by Corine J. Verhoeven, Chelly Nuij, Christel R.M. Janssen-Rolf, Ewoud Schuit, Joke M.J. Bais, S. Guid Oei, Ben Willem J. Mol [Eur J Obstet Gynecol Reprod Biol 200 (2016) 29–34]. §
332
grant to conduct a randomized control trial exploring whether trans-venous occlusion of pelvic vein incompetence improves symptoms and quality of life in women with PVI and chronic pelvic pain. The results of this study are due to be published in 2018 [1]. We hope that completion of this trial and our case control study will make a significant contribution to the epidemiology of PVI, its role in chronic pelvic pain, and to its subsequent management. Reference [1] Trans-venous occlusion of pelvic vein incompetence. ISRCTN Registry. BioMed Central. http://dx.doi.org/10.1186/ISRCTN15091500 [accessed http://www. isrctn.com/ISRCTN15091500].
diagnostic rigor to consider factors that have been known for a long time to be associated with risk of failure (i.e. any head above the brim of the pelvis at the commencement of the AVD). In our study it was seen that the risk of failure in ‘trials of vacuum extraction’ (59 cases) was 20% and the overall risk of failure for vacuum extraction procedures that were not set up as a trial (689 cases) was 1.8%. Lastly, when there is an obstetric factor that the vacuum extractor is able to correct (most notably deflexon and posterior position), then the odds ratios (OR) for failure should be <1. If this is not the case then the operators are not placing the cup over the flexion point either because they not using posterior cups (or omnicups) or their technique is faulty. Yours sincerely
V. Hansrani D.M. Riding Charles McCollum* Academic Surgery Unit, Institute of Cardiovascular Sciences, 2nd Floor, Education and Research Centre, University Hospital of South Manchester, Manchester, UK
Glen Mola School of Medicine and Health Sciences, UPNG, Papua New Guinea
10 March 2016 *Corresponding author E-mail address: [email protected] (C. McCollum).
http://dx.doi.org/10.1016/j.ejogrb.2016.05.021
http://dx.doi.org/10.1016/j.ejogrb.2016.04.017
Trials of Vacuum Extraction
Authors’ response: Re. Predictors for failure of vacuum-assisted vaginal delivery: a case-control study
Dear Editors,
Dear Editors,
I refer to the article in the European Journal of Obstetrics and Gynecology and Reproductive Biology, May 2016, Volume 200, Pages 29–34, ‘Predictors for failure of vacuum-assisted vaginal delivery: a case–control study’ by Corine J.M. Verhoeven, Chelly Nuij, Christel R.M. Janssen Rolf, Ewoud Schuit, Joke M.J. Bais, S. Guid Oei, Ben Willem J. Mol. We did a study on predictors of failure in ‘Trials of Vacuum Extraction’’ (Mola GDL, Amoa AB, Edilyong J, Factors associated with success or failure in trials of vacuum extraction, Aust NZ J Obstet Gynecol, 2002, Vol. 42, 41–45). I see that in the Dutch study all attempts at vacuum extraction were considered a ‘trial’. I suppose this is true in some ways that any attempt at any procedure may fail, but traditionally ‘a trial of assisted delivery’ has been a very particular clinical scenario where the operator considers that there is a significant risk of failure, and the procedure is usually therefore carried out with set up for immediate recourse to a secondary delivery method (CS or symphysiotomy) should failure occur. It is particularly important when one is conducting AVD in poorly resourced settings (e.g. most developing countries in the world) where recourse to the backup delivery option may take several hours to organize. Under these circumstances a failed AVD (when there was no set up for ‘‘A Trial’’) is considered an ‘unexpected failure’. Unexpected failures in less resourced settings are to be avoided at much as possible as a delay in delivering the fetus of several hours after a failed AVD always leads to poorer fetal outcomes. Perhaps it is the ability in the developed world of being able to perform a CS within a few minutes (whether the failed AVD was ‘unexpected’ or not) and the very much increased risk of failure when the woman has had an epidural, that has led to loss of clinical
We thank professor Mola for his interest in our study and his comments. Professor Mola questions the definition of ‘a trial of assisted delivery’ as we used in our study. In his study he considers a trial of assisted delivery as an attempt of vacuum assisted delivery with a significant risk of failure, whereby the procedure usually is carried out in the operating theatre [1]. In our study we considered all attempts at vacuum extraction a ‘trial’. We agree with professor Mola that any attempt at any procedure may fail. Indeed, this was what we tried to predict. We feel that assessing all attempted vacuum assisted deliveries is the best approach here. In our study, a posterior position was a significant risk factor for failed vacuum-assisted delivery with an adjusted odds ratio of 3.0 (95% CI 2.0–4.6). While professor Mola may argue that this position can be corrected, we show that deflexion and occiput posterior (OP) position increases the risk of failure. We challenge professor Mola to present data on a series of patients where he turns the baby form OP position to OA position while keeping the risk of failure low. Our study shows that failed vacuum assisted delivery can be predicted. However, there is a strong need for validation of our model in a prospective observational study. We hope that this answer will help in using the data that we supplied. On behalf of the authors,
DOI of original article: http://dx.doi.org/10.1016/j.ejogrb.2016.05.021 Original article: ‘‘Predictors for failure of vacuum-assisted vaginal delivery: a case-control study’’, by Corine J. Verhoeven, Chelly Nuij, Christel R.M. Janssen-Rolf, Ewoud Schuit, Joke M.J. Bais, S. Guid Oei, Ben Willem J. Mol [Eur J Obstet Gynecol Reprod Biol 200 (2016) 29–34]. §