title: Vacuum-assisted vaginal delivery simulation--quantitation of subjective measures of traction and detachment forces.
abstract: OBJECTIVE
  Excessive traction has been alleged as the cause of newborn complications associated with vacuum delivery. We sought to quantify subjective levels of physician vacuum traction in a simulated obstetric delivery model, dependent upon level of training.
  
  
  METHODS
  Three groups of physicians, based on training level applied traction (minimal, average, maximal) on a pre-applied vacuum model and forces were continually recorded. Detachment force was recorded with traction in both the pelvic axis and at an oblique angle.
  
  
  RESULTS
  Quantified traction force increased from subjective minimal to average to maximal pulls. Within each level, there were no differences between the groups in the average traction force. Detachment force was significantly less when traction was applied at an oblique angle as opposed to the pelvic axis (11.1 ± 0.3 vs 12.2 ± 0.3 kg).
  
  
  CONCLUSIONS
  Providers appear to be good judges of the force being applied, as a clear escalation in force is noted with minimal, average and maximal force pulls. There appears to be a relatively short learning curve for use of the vacuum, as junior residents' applied force was not different from those of more experienced practitioners. Using the KIWI device, detachment force is lower when traction is applied at an oblique angle.
authors.affiliation: Department of Obstetrics and Gynecology, David Geffen School of Medicine at UCLA, Torrance, CA 90502, USA.
authors.forename: Ramy
authors.initials: R
authors.lastname: Eskander
authors.forename: Marie
authors.initials: M
authors.lastname: Beall
authors.forename: Michael G
authors.initials: MG
authors.lastname: Ross
mesh_terms: D001696:Biomechanical Phenomena; D005180:Faculty, Medical; D006801:Humans; D007396:Internship and Residency; D059032:Learning Curve; D008505:Medical Staff, Hospital / Q000523:psychology; D008953:Models, Anatomic; D010465:Perception; D010820:Physicians / Q000523:psychology; D011446:Prospective Studies; D014620:Vacuum Extraction, Obstetrical / Q000295:instrumentation / Q000379:methods / Q000523:psychology