title: Rapid versus stepwise application of negative pressure in vacuum extraction-assisted vaginal delivery: a multicentre randomised controlled non-inferiority trial.
abstract: OBJECTIVE
  To evaluate whether the application of rapid negative pressure for vacuum-assisted delivery is as effective and safe as the stepwise method.
  
  
  METHODS
  Randomised controlled trial.
  
  
  METHODS
  Six centres, including university, secondary and tertiary hospitals, in Thailand.
  
  
  METHODS
  In total, 662 women were randomised to rapid and stepwise groups, with 331 women in each group.
  
  
  METHODS
  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.
  
  
  METHODS
  Success rate of vacuum extraction, vacuum cup detachment rate, duration of vacuum extraction, and maternal and neonatal complications.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  Rapid negative pressure vacuum extraction could be performed as effectively and safely as the stepwise method, in a shorter period of time.
authors.affiliation: Department of Obstetrics and Gynaecology, Kalasin Hospital, Kalasin, Thailand.
authors.forename: B
authors.initials: B
authors.lastname: Suwannachat
authors.forename: M
authors.initials: M
authors.lastname: Laopaiboon
authors.forename: S
authors.initials: S
authors.lastname: Tonmat
authors.forename: T
authors.initials: T
authors.lastname: Siriwachirachai
authors.forename: S
authors.initials: S
authors.lastname: Teerapong
authors.forename: N
authors.initials: N
authors.lastname: Winiyakul
authors.forename: J
authors.initials: J
authors.lastname: Thinkhamrop
authors.forename: P
authors.initials: P
authors.lastname: Lumbiganon
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D014620:Vacuum Extraction, Obstetrical / Q000379:methods*