Anesthesia for Complicated Vaginal Deliveries

Abstract

Summary Abnormal presentations complicate approximately 4% of all deliveries. The majority of these infants are in the breech presentation. Recent data suggest that vaginal delivery of the breech infant may be as safe as cesarean section. Epidural analgesia is preferred for vaginal delivery of the breech presentation. Sacral block may prevent premature maternal pushing and thus decrease the likelihood of cervical head entrapment. During delivery the obstetrician attempts to minimize trauma to the fetal head and neck. On occasion, general anesthesia is necessary to relieve cervical entrapment. The anesthesiologist should be prepared to administer general anesthesia to every patient with a breech presentation. Multiple gestation complicates approximately 1 to 2% of all pregnancies. The physiologic changes of pregnancy are exaggerated with multiple gestation. For twin gestations, the presentation of the fetuses may influence the mode of delivery. Epidural analgesia is preferred for vaginal delivery. If a spontaneous delivery is planned, the motor block should be minimized. If internal podalic version and extraction of twin B is planned, epidural anesthesia alone may be sufficient. But, on occasion, general anesthesia is required for delivery of the second twin. Specifically, administration of a potent halogenated agent will relax the uterus and facilitate delivery of the second twin. For gestations of greater than two, delivery is generally performed via cesarean section. Either regional or general anesthesia is acceptable depending on the condition of the mother. Shoulder dystocia occurs in up to 2% of vaginal deliveries. The dystocia is often relieved by changing the rotation of the maternal pelvis or changing the fetal position. Rarely, general anesthesia and skeletal muscle relaxation may be necessary. Following delivery the infant tends to be depressed and may require resuscitation. Rarely, the fetus cannot be delivered vaginally, is returned to the uterus, and delivered by cesarean section. Retained placenta occurs in 1% of deliveries. Often there is significant blood loss with a retained placenta. Patients may require anesthesia for uterine exploration and removal of a retained placenta. General anesthesia with a potent halogenated agent provides cervical and uterine relaxation, which facilitates exploration. These patients must be considered to have a full stomach, and precautions must be taken to prevent against regurgitation and aspiration.