Rapid versus stepwise application of negative pressure in vacuum extraction-assisted vaginal delivery: a multicentre randomised controlled non-inferiority trial. Stepwise compared with rapid application of vacuum in ventouse extraction procedures.
To evaluate whether the application of rapid negative pressure for vacuum-assisted delivery is as effective and safe as the stepwise method.
                Randomised controlled trial.
                Six centres, including university, secondary and tertiary hospitals, in Thailand.
                In total, 662 women were randomised to rapid and stepwise groups, with 331 women in each group.
                Vacuum extraction was performed by applying a metal cup (Malmstrom) connected to an electric pump to the fetal head. The stepwise method consisted of four incremental steps of 0.2 kg/cm² every 2 minutes to obtain a final negative pressure of 0.8 kg/cm². In the rapid method the negative pressure of 0.8 kg/cm² was applied in one step in < 2 minutes.
                Success rate of vacuum extraction, vacuum cup detachment rate, duration of vacuum extraction, and maternal and neonatal complications.
                There were no significant differences in detachment rates (RD 0.3%, 95% CI -3.1 to 2.4). The overall success rates were identical, at 98.2%. There were significant reductions in the time between applying the vacuum cup and attaining maximum negative pressure (MD -4.6 minutes; 95% CI -4.4 to -4.8 minutes), and in the time between applying the cup and delivery (MD -4.4 minutes; 95% CI -4.8 to -4.0 minutes). There was a significantly higher rate of perineal suture in the rapid method group (RD 4.5%; 95% CI 1.1-8.2). There were no significant differences in maternal and fetal morbidities.
                Rapid negative pressure vacuum extraction could be performed as effectively and safely as the stepwise method, in a shorter period of time.
                © 2011 The Authors BJOG An International Journal of Obstetrics and Gynaecology © 2011 RCOG. To compare a one-step (rapid) application of negative pressure (vacuum) with conventional stepwise application for ventouse extraction following a prolonged second stage of labour.
                Randomised controlled study.
                Teaching Hospital.
                Forty-seven women were randomised to the rapid vacuum group and 47 to the stepwise group.
                Duration of ventouse procedure, effectiveness of methods of application, morbidity of mother and infant.
                There was no significant difference in frequency of detachment of the cup after rapid or stepwise application of vacuum. A reduction in mean duration of the ventouse procedure of 6 min was realised without significant difference in maternal or neonatal morbidity.
                Rapid application of vacuum significantly reduces the duration of a ventouse extraction procedure without compromise to efficiency and safety.
The rapid negative pressure application for vacuum assisted vaginal birth reduces duration of the procedure whilst there is no evidence of differences in maternal and neonatal outcomes. Rapid method of negative application should be recommended for vacuum extraction assisted vaginal delivery.