Traction force during vacuum extraction: a prospective observational study
2015 (English)In: British Journal of Obstetrics and Gynecology, ISSN 1470-0328, E-ISSN 1471-0528, Vol. 122, no 13, 1809-1816 p.Article in journal (Refereed) PublishedText
ObjectiveTo investigate the traction force employed during vacuum extractions. DesignObservational cross-sectional study. SettingObstetric Department, Karolinska University Hospital, Sweden, and the Swedish National Congress of Obstetrics and Gynaecology, 2013. PopulationTwo hundred women with vacuum extraction at term and 130 obstetricians participating in a simulated setting. MethodsIn a normal clinical setting, we used a specially adapted device to measure and record the force used to undertake vacuum extraction. In a subsequent part of the study, the force employed for vacuum extraction by a group of obstetricians in a fictive setting was estimated and objectively measured. Main outcome measuresApplied force during vacuum extraction in relation to the estimated level of difficulty in the delivery; perinatal diagnoses of asphyxia or head trauma; estimated force compared with objectively measured force employed in the fictive setting. ResultsThe median (minimum-maximum) peak forces for minimum, average and excessive vacuum extraction in the clinical setting were 176N (5-360N), 225N (115-436N), and 241N (164-452N), respectively. In 34% of cases a force in excess of 216N was employed. There was no correlation between the umbilical arterial pH at delivery and the traction force employed during extraction. Four cases of mild hypoxic ischaemic encephalopathy were observed, three of which were associated with a delivery whereby excessive traction force was employed during the vacuum extraction. In the fictive setting, the actual exerted force was twice the quantitative estimation. The measured forces in the clinical setting were four times higher than that estimated in the fictive setting. ConclusionsHigher than expected levels of traction force were used for vacuum extraction delivery. As obstetricians tend to underestimate the force applied during vacuum extraction, objective measurement with instantaneous feedback may be valuable in raising awareness.
Place, publisher, year, edition, pages
Wiley-Blackwell, 2015. Vol. 122, no 13, 1809-1816 p.
Failed vacuum extraction, traction force, vacuum extraction
Obstetrics, Gynecology and Reproductive Medicine
IdentifiersURN: urn:nbn:se:kth:diva-180240DOI: 10.1111/1471-0528.13222ISI: 000365452200014PubMedID: 25558833ScopusID: 2-s2.0-84947617239OAI: oai:DiVA.org:kth-180240DiVA: diva2:891916
QC 201601082016-01-082016-01-082016-01-08Bibliographically approved