Retinal hemorrhages and traction forces in vacuum extraction

Survey of retinal haemorrhages in neonatal thoroughbred foals

“…In some foals there were differences in the numbers, distribution patterns, and type of haemorrhages in each eye. Similar differences have been recorded in babies (Maltau and Egge 1980, Svenningsen and others 1988) but no explanation is known. In this survey, the type of haemorrhage appeared to be related to the numbers found, with the punctate type usually occurring in small numbers, and the splash type often occurring in groups of more than 10.…”

“…The incidence of retinal haemorrhages varies with the population of children studied (Baum and Bulpitt 1970, Besio and others 1979, Levin and others 1980, Egel and others 1988, Svenningsen and Eidal 1988). The thoroughbred horse is a highly selected breed, and there may well be a significant difference in the incidence of retinal haemorrhages between different breeds.…”

Validation of traction force indicator in ventouse devices

“…The correct application of the vacuum cup, and traction directed in line with the axis of the pelvis, will ensure that optimal diameters of the fetal head are presenting at all levels in the birth canal and that vacuum delivery will be effected with minimal traction force. In a study by Svenningsen [9], a vacuum extraction recorder was used to provide an objective measurement of the traction forces exerted on the fetal head during 120 vacuum extractions. In half of the deliveries the suction pressure was increased gradually and stepwise to 0.8 kg/cm 2 before traction.…”

“…In fact, once an adequate level of vacuum had been achieved, high traction forces could be applied to the suction cup regardless of the rate at which the vacuum was obtained. Furthermore, the number and nature of neonatal complications were not influenced by the method chosen [9]. Indeed, Lim and coworkers found that, by applying suction pressure rapidly, there was a 6‐min reduction in the mean duration of the procedure without significant differences in maternal or neonatal morbidity [10].…”

Association of traction force and adverse neonatal outcome in vacuum‐assisted vaginal delivery: A prospective cohort study

“…25 A similar concept has been used in previous studies under the name force time 9 or force time integral. 17,26 In our method, however, the peak and total traction forces are recorded electronically, thereby minimizing human measurement error. The equipment was described in detail in a previous study.…”