Anesthesia for Postpartum Hemorrhage

POSTPARTUM HEMORRHAGE

Postpartum hemorrhage is the leading cause of maternal mortality in developing countries. It is diagnosed when the postpartum blood loss exceeds 500 mL. Up to 4% of parturients may experience postpartum hemorrhage, which is often associated with a prolonged third stage of labor, preeclampsia, 15 multiple gestations, and forceps delivery.

Common causes include uterine atony, a retained placenta, obstetric lacerations, uterine inver-sion, and use of tocolytic agents prior to delivery. Atony is often associated with uterine overdistention (multiple gestation and polyhydramnios). Less com-monly, a clotting defect may be responsible.

The anesthesiologist may be consulted to assist in venous access or fluid (and blood) resuscitation, as well as to provide anesthesia for careful examination of the vagina, cervix, and uterus. Perineal lacerations can usually be repaired with local anesthetic infiltra-tion or pudendal nerve blocks. Residual anesthesia from prior epidural or spinal anesthesia facilitates examination of the patient; however, supplementa-tion with an opioid, nitrous oxide, or both may be required. Induction of spinal or epidural anesthe-sia in the presence of hypovolemia is problematic.

General anesthesia is usually required for manual extraction of a retained placenta, reversion of an inverted uterus, or repair of a major lacera-tion. Uterine atony should be treated with oxytocin (20–30 units/L of intravenous fluid), methylergono-vine (0.2 mg intramuscularly or in 100 mL of nor-mal saline administered over 10 min intravenously), and prostaglandin F_2α (0.25 mg intramuscularly). Emergency laparotomy and hysterectomy may be necessary in rare instances. Early ligation of the internal iliac (hypogastric) arteries may help avoid hysterectomy or reduce blood loss.