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
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 F2α (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.