Vacuum extractors: Description, mechanics, indications and contra-indications
The vacuum extractor, as opposed to other instruments, does not increase the fetal head diameter for vaginal delivery. Introduced half a century ago, this device is today widely used in many countries probably because of a learning-curve which is acquired quicker than for the forceps. Major benefits obtained are the flexion of the fetal head provided that the cup is correctly placed, and the compulsory rotation induced that is most useful in the conversion of occiput posterior or transverse to anterior positions. The limitations reside in the need for maternal effort at expulsion and in the fact that it is unsuitable for face presentations. Moreover, like other instruments, the vacuum extractor can be harmful and even dangerous to the mother and her fetus. Therefore, its indications and contra-indications must be respected, and its operative use mastered with as much precision as for the forceps.
[Show abstract] [Hide abstract] ABSTRACT: Background: Assisted vaginal delivery by vacuum extraction is frequent. Metallic resterilizible metallic vacuum cups have been routinely used in France. In the last few years a new disposable semi-soft vacuum extraction cup, the iCup, has been introduced. Our objective was to compare maternal and new-born outcomes between this disposable cup and the commonly used Drapier-Faure metallic cup. Methods: This was a multicenter prospective randomized controlled open clinical trial performed in the maternity units of five university hospitals and one community hospital in France from October 2009 to February 2013. We included consecutive eligible women with a singleton gestation of at least 37 weeks who required vacuum assisted delivery. Women were randomized to vacuum extraction using the iCup or usual Drapier-Faure metallic cup. The primary outcome was a composite criterion including both the risk of cup dysfunction and the most frequent maternal and neonatal harms: the use of other instruments after attempted vacuum extraction, caesarean section after attempted vacuum extraction, three detachments of the cup, caput succedaneum, cephalohaematoma, episiotomy and perineal tears. Results: 335 women were randomized to the disposable cup and 333 to extraction using the metallic cup. There was no significant difference between the two groups for the primary outcome. However, failed instrumental delivery was more frequent in the disposable cup group, mainly due to detachment: 35.6 % vs 7.1 %, p < 0.0001. Conversely, perineal tears were more frequent in the metallic cup group, especially third or fourth grade perineal tears: 1.7 % versus 5.0 %, p = 0.003. There were no significant differences between the two groups concerning post-partum haemorrhage, transfer to a neonatal intensive care unit (NICU) or serious adverse events. Conclusions: While the disposable cup had more detachments and extraction failures than the standard metallic cup, this innovative disposable device had the advantage of fewer perineal injuries. Trial registration: www.clinicaltrials.gov : NCT01058200 on Jan. 27 2010.
- "In addition, equivalence trials remain controversial, among specialists there is rarely an 'agreed efficacy loss' and furthermore there is rarely consensus among specialists. The components of the composite endpoint used here are the criteria most frequently used when assessing the benefit-risk balance of instrumental vaginal deliveries by ventouse [2, 3, 5]. Although the clinical trial was not blinded, it was randomized and it included nearly 600 women in six centres. "
- [Show abstract] [Hide abstract] ABSTRACT: Forceps, vacuum, and cesarean sections are relatively recent additions to the obstetrician's armamentarium. The art of modern obstetrics is one that mandates from obstetricians the attentive vigilance of the development of natural processes and an active intervention when such processes fall outside normally accepted standards. What constitutes the "normal process" and the "accepted standard" is subject to discussion, and international variations in obstetric practice are in part the reflection of such controversies. This article presents a practical approach to the contemporary issue of instrumental deliveries, outlining supporting evidence (when available) and the most current position of professional colleges in obstetrics and gynecology.
- [Show abstract] [Hide abstract] ABSTRACT: Routine use of a partograph is associated with a reduction in the use of forceps, but is not associated with a reduction in the use of vacuum extraction (Level A). Early artificial rupture of the membranes, associated with oxytocin perfusion, does not reduce the number of operative vaginal deliveries (Level A), but does increase the rate of fetal heart rate abnormalities (Level B). Early correction of lack of progress in dilatation by oxytocin perfusion can reduce the number of operative vaginal deliveries (Level B). The use of low-concentration epidural infusions of bupivacaine potentiated by morphinomimetics reduces the number of operative interventions compared with larger doses (Level A). Placement of an epidural before 3-cm dilatation does not increase the number of operative vaginal deliveries (Level A).