A prospective randomised controlled trial of the Kiwi Omnicup versus conventional ventouse cups for vacuum-assisted vaginal delivery
We thank Dr Senanayake1 for his comments regarding our article ‘A prospective randomised controlled trial of the Kiwi Omnicup versus conventional ventouse cups for vacuum assisted vaginal delivery’.2 We agree that the failure rate for the Kiwi Omnicup in our series was very high and very different to the rate reported by Vacca.3 Our study was a pragmatic randomised controlled trial designed to be a true reflection of what happens on the ‘shopfloor’ in a clinical setting rather than that achieved by experts. Our study, similar to the randomised controlled trial by Attilakos et al.,4 showed a significant difference between delivery failure rates for the Kiwi Omnicup and conventional ventouse cups.
Incorrect cup placement is almost certainly a factor in the high failure rate of the Kiwi Omnicup, as it is for all ventouse deliveries4 and our study demonstrated this. The failure rate for incorrectly positioned Kiwi Omnicup was 45.7% compared with 24.1% for correctly positioned cups. We attempted to assess the impact of cup placement by asking each clinician to examine the neonate after the delivery and mark diagrammatically the cup position relative to the flexion point (defined in the same way as Dr Senanayake, i.e. 3 cm in front of the posterior fontanelle). This was subjective as each clinician made their own assessment. Our study did not have sufficient funding for an independent observer to make this assessment. Despite this, the method used to assess cup placement and, indeed, the individuals placing the cups were the same for both groups, and a demonstrable difference in failure rates was still evident. This suggests that although incorrect placement contributed to failed delivery, additional factors were also involved.
We agree with Dr Senanayake that high failure rates are associated with a lack of adequate training in vacuum-assisted delivery. High quality ‘in service’ training is vital for all instrumental vaginal deliveries, but in the UK, this is limited by the relatively small number of senior staff compared with junior trainees and the limited opportunities for training which have resulted from a service-driven culture. Teaching with mannequins has been of limited value to date as they are so unrealistic, but a new obstetric model designed by Aldo Vacca and soon to be available commercially should help substantially in this difficult task. We hope that our study highlights the need for more intensive ‘hands-on’ teaching in assisted vaginal delivery.