A RANDOMIZED TRIAL OF 2 VACUUM EXTRACTION TECHNIQUES

Objective: To determine whether two techniques of vacuum extraction de livery-continuous vacuum and intermittent vacuum-have different effect s on maternal-fetal outcomes. Methods: Patients to be delivered by vac uum extraction were randomized to receive continuous or intermittent v acuum. All deliveries were performed using the M-cup. In the continuou s group, the level of vacuum was brought to 600 mmHg between contracti ons and was maintained at that level until delivery of the infant. Act ive efforts were made to prevent fetal loss-of-station between contrac tions by maintaining traction. In the intermittent group, the level of vacuum was decreased to 100 mmHg between contractions and no effort w as made to prevent fetal loss-of-station. Results: A total of 322 pati ents were randomized: 164 in the continuous arm and 158 in the intermi ttent group. The continuous method did not effect delivery faster (con tinuous 167 +/- 175 seconds versus intermittent 167 +/- 150 seconds; P = .97), nor did it lead to a reduction in method failures (continuous 12, intermittent nine; P = .72). The intermittent method did not appe ar to offer any benefit to the neonate regarding cephalhematoma format ion (continuous 20, intermittent 17; P = .686) or any other measure of neonatal outcome. Maternal lacerations and episiotomy extensions were evenly distributed between the groups. Overall, the efficacy rate of the vacuum cup was 93.5% and the cephalhematoma rate was 11.5%. Conclu sion: No differences in maternal or fetal outcome could be demonstrate d if the level of vacuum was decreased between contractions or if an e ffort was made to prevent fetal loss-of-station. The clinical results obtained in this trial using the M-cup are similar to the published re sults with the stainless-steel Malmstrom cup. (C) 1997 by The American College of Obstetricians and Gynecologists.