Effect of angular traction on the performance of modern vacuum extractors.
Am J Obstet Gynecol
; 167(4 Pt 1): 1125-9, 1992 Oct.
Article
em En
| MEDLINE
| ID: mdl-1415403
ABSTRACT
OBJECTIVE:
Our objective was to describe the effect of off-axis traction on the performance of modern vacuum extractors. STUDYDESIGN:
Eight vacuum extractors were examined in the laboratory with a force indicator and fetal cephalic model. Devices evaluated included the 6 cm Malmstrom, Mity-Vac, M-Type, O'Neil, Posterior, Silc, Tender-Touch, and silicone elastomer. Maximal tractive force (pop-off) was measured for each device at 10-degrees increments from the vertical.RESULTS:
Multivariate regression analysis described the best model as follows Maximal tractive force = Constant + Angle + Vacuum (p < 0.05). The partial regression coefficients for angle were negative in all devices except the Posterior cup. At increasing angles of off-axis traction, maximal tractive force decreased in the following order Silc, silicone elastomer, Tender-Touch, M-Type, Mity-Vac, O'Neill, Malmstrom, and Posterior.CONCLUSIONS:
Application of oblique traction resulted in a linear decline in maximal tractive force. An understanding of in vitro performance may allow tailoring of cup selection to the clinical situation.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Tração
/
Vácuo-Extração
Tipo de estudo:
Diagnostic_studies
/
Evaluation_studies
/
Prognostic_studies
Limite:
Female
/
Humans
/
Pregnancy
Idioma:
En
Revista:
Am J Obstet Gynecol
Ano de publicação:
1992
Tipo de documento:
Article