Eclampsia is an obstetric emergency. Inadequate preparation for it or an inappropriate response to maternal and fetal conditions during and after an eclamptic convulsion can be detrimental to the mother and fetus. All obstetric units should have up-to-date protocols in place and should conduct mandatory drills to prepare nursing staff, obstetric providers, and anesthesia staff working in these units to manage eclampsia.
During a seizure, resist the impulse to administer anticonvulsive drugs, including intravenous (IV) magnesium sulfate, because most eclamptic convulsions are self-limiting. Also abstain from administering medications such as IV phenytoin, diazepam, or midazolam, as these drugs are less effective than magnesium sulfate, and some can suppress the laryngeal reflex, increasing the risk of aspiration.
If the patient develops status epilepticus, initiate muscle paralysis and intubate her.
It is vital to support maternal respiratory and cardiovascular functions to prevent hypoxia, acidosis, and cardiorespiratory arrest.
Begin by establishing airway patency and maternal oxygenation during and after the convulsion. Administer oxygen via a face mask, with or without a reservoir, at a rate of 8 to 10 L/min.
During the apneic period (see “Profile of an eclamptic seizure” on page 46), the patient will develop hypoxia. Use pulse oximetry to monitor oxygen saturation, with the goal of keeping it above 94%. Arterial blood gas analysis is required if oxygen saturation remains below 92% or if pulmonary edema or aspiration is suspected.
If the patient develops recurrent seizures, status epilepticus, florid alveolar pulmonary edema, or respiratory arrest, intubate her immediately.
Secure the side rails of the patient’s bed by elevating them to prevent a fall, and make sure they are padded to prevent trauma during convulsions and afterward, when some women become combative and agitated. Position the patient in a lateral decubitus position to minimize aspiration of oral secretions. If any secretions or vomitus are present, remove them via suction.
Magnesium is the drug of choice for seizure prophylaxis in women with preeclampsia and severe symptoms, and to prevent recurrent seizures in women with eclampsia.
In the latter group, once the eclamptic convulsion has ended, give a loading dose of IV magnesium (6 g/100 mL over 20 minutes), followed by a continuous infusion of 2 g/h for at least 24 hours. If the patient develops a second seizure during the maintenance infusion, administer another bolus of magnesium (2 g/100 mL over 3–5 minutes).
If severe hypertension persists for 60 minutes or longer, it can lead to injury of the brain, heart, and kidneys. To avoid these complications, it is essential to reduce BP to a safe range and maintain that level without compromising cerebral perfusion pressure and uteroplacental blood flow (which already may be reduced in some patients).
The goal of antihypertensive therapy is to keep systolic BP between 140 and 155 mm Hg and diastolic values between 90 and 105 mm Hg.9 Several agents are available for the treatment of severe hypertension during pregnancy and postpartum. The most commonly used IV medications for this purpose are labetalol and hydralazine. Another option is oral, rapidly acting
nifedipine.
Several randomized trials have compared efficacy and side effects between IV bolus injections of hydralazine; IV labetalol; and oral, rapidly acting nifedipine. In general, the findings of these studies suggest that either IV hydralazine or labetalol or oral nifedipine can be used to treat severe hypertension in pregnancy, as long as the provider is familiar with the dose to be used, the expected onset of action, and potential side effects (TABLE 3).
Women who develop generalized swelling or hemoconcentration (hematocrit ≥40%), or both, usually experience markedly reduced plasma volume. For this reason, these women will benefit from treatment with labetalol. If this is ineffective, then add IV hydralazine. However, delay administration of a rapidly acting vasodilator such as hydralazine to prevent an excessive hypotensive response and a secondary reduction in tissue perfusion and uteroplacental blood flow. Rather, administer a bolus infusion of 250 to 500 mL of isotonic saline before giving a vasodilator.
Additional details about the use of antihypertensive drugs are given in the section on other hypertensive emergencies below.
Pulmonary edema can develop in patients with eclampsia or another hypertensive emergency. Suspect it if the patient has respiratory symptoms in association with tachypnea, tachycardia, or sustained oxygen saturation values below 93%, as well as when the patient exhibits basal rales during auscultation of the lungs. Treatment involves the administration of oxygen and IV furosemide (20–40 mg push), repeated as needed.
