Critically ill obstetric patients: Delivering the right care
EXPERT ANALYSIS AT THE UCSD CRITICAL CARE SUMMER SESSION
For patients with severe preeclampsia, the focus is on improving placental perfusion through optimizing maternal cardiac output and peripheral vasodilation. "Most patients with pregnancy-induced hypertension are volume depleted and require careful volume repletion," she said. "Continuous fetal monitoring is also warranted."
In cases of severe preeclampsia, magnesium sulfate is the standard seizure prophylaxis. Dr. Robbins and her associates typically give a loading dose of 4-6 grams over 20 minutes, and then they run an infusion of 1-2 g/hr to keep the patient in a range of 4-8 mg/dL. "We can start to see toxicity such as loss of deep tendon reflexes at magnesium levels above 10 mg/dL," she said.
Hallmark agents for blood pressure control include hydralazine and labetalol. "You want to avoid rapid vasodilation and manage fluids in a goal-directed fashion," she said. "You may see these patients receiving steroids if their gestational age is less than 34 weeks. That’s to help with fetal lung maturity."
If preeclampsia progresses to seizures, magnesium therapy is the mainstay of treatment. "Once the patient is stabilized, she should undergo a neurologic evaluation and imaging to rule out other things such as stroke, hemorrhage, epilepsy, or a tumor," she said. "The highest risk of morbidity in this group of patients is from cerebrovascular events, including both ischemic and hemorrhagic events."
Patients with preeclampsia face an increased risk for HELLP syndrome, which stands for hemolysis, elevated liver enzymes, and low platelets. "The treatment here is delivery of the fetus and other supportive measures," Dr. Robbins said. Steroids have not been shown to be beneficial (Am. J. Obstet. Gynecol. 2005;193:1591-8). The clinical course of patients with HELLP syndrome "is fraught with complications, including liver hematoma rupture and renal failure, so you need to be prepared for that."
Dr. Robbins also discussed obstetric hemorrhage, which is the second-leading cause of pregnancy-related death in the United States and is the leading cause in developing countries. Hemorrhage is defined as losing greater than 500 mL of blood at vaginal delivery or greater than 1,000 mL after cesarean section. "Life-threatening hemorrhage can occur in the antepartum or postpartum period," she said. Antepartum hemorrhage is usually associated with placenta previa or abruption, while postpartum hemorrhage is most often associated with uterine atony. Risk factors for postpartum hemorrhage include preexisting anemia, obesity, fetal macrosomia, prior cesarean sections, and multiple gestations. "In these patients, disseminated intravascular coagulation may develop because of the dilutional effects of massive transfusion or some other underlying process," she said.
Treatment of obstetric hemorrhage includes volume resuscitation, correction of coagulopathy, maintaining adequate tissue perfusion, and controlling the source of blood loss. "Patients with uterine atony can be treated with uterine massage or with uterotonic drugs such as oxytocin, Methergine [methylergonovine], Hemabate [carboprost], and misoprostol," Dr. Robbins said. Surgical treatments such as uterine compression sutures or hysterectomy may be required.
Dr. Robbins said that she had no relevant financial conflicts to disclose.
