A randomised controlled trial of a new handheld vacuum extraction device

Abstract

To evaluate the effectiveness of a new handheld vacuum delivery device. Randomised controlled trial. Southmead Hospital, Bristol, UK. One hundred and ninety-four women requiring delivery with vacuum extraction. Women were recruited into the study while still in early labour. If during delivery, vacuum extraction was indicated they were then randomly allocated to either a new handheld vacuum device, the Kiwi Omnicup, or to a 'standard' vacuum cup selected by the obstetrician. The 'standard group' consisted of the silastic (66/98, 67%) or the metal cups (32/98, 33%). Study data were recorded at completion of the delivery and at 24-48 hours. An additional brief symptom questionnaire was completed by the mother at 10 days postnatally. Statistical analyses were done on an 'intention-to-treat' basis. The primary outcome was the successful completion of delivery with the allocated instrument. Secondary outcomes were substantial fetal scalp trauma and substantial maternal trauma. The Omnicup was associated with a significantly higher failure rate than the standard cup [34%vs 21%, odds ratio (OR) = 1.9 (1.01-3.6)]. This difference persisted after adjusting for confounding factors [adjusted OR = 2.25 (1.01-5.0)] and resulted in significantly more forceps deliveries in the Kiwi Omnicup group [22%vs 10%, unadjusted OR = 2.5 (1.1-5.5)]. The caesarean section rates were similar in both groups [9.4%vs 8.2%, OR = 1.2 (0.4-3.2)]. Rates of substantial scalp trauma and maternal trauma were similar in both groups. However, there were more cases of jaundice in the standard cup group [2.3%vs 12.0%, unadjusted OR = 0.18 (0.04-0.82) and adjusted OR = 0.10 (0.01-0.88)]. The Omnicup is not as successful at achieving a vaginal delivery as the combination of the currently used vacuum cups.