Managing an eclamptic patient
Most Ob/Gyns have little experience managing acute eclampsia, but all maternity units and obstetricians need to be prepared to diagnose and manage this grave threat.
Other diseases may factor in
Some women develop gestational hypertension or preeclampsia in association with connective tissue disease, thrombophilias, seizure disorder, or hypertensive encephalopathy, further confounding the diagnosis.
Thus, make every effort to ensure a correct diagnosis, since management may differ among these conditions.
Managing convulsions
Do not try to stop the first convulsion
The natural tendency is to try and interrupt the convulsion, but this is not recommended. Nor should you give a drug such as diazepam to shorten or stop the convulsion, especially if the patient lacks an intravenous line and no one skilled in intubation is immediately available. If diazepam is given, do not exceed 5 mg over 60 seconds. Rapid administration of this drug may lead to apnea or cardiac arrest, or both.
Steps to prevent maternal injury
During or immediately after the acute convulsive episode, take steps to prevent serious maternal injury and aspiration, assess and establish airway patency, and ensure maternal oxygenation (TABLE 4).
Elevate and pad the bed’s side rails and insert a padded tongue blade between the patient’s teeth, taking care not to trigger the gag reflex.
Physical restraints also may be needed.
Prevent aspiration. To minimize the risk of aspiration, place the patient in the lateral decubitus position, and suction vomitus and oral secretions as needed. Be aware that aspiration can occur when the padded tongue blade is forced to the back of the throat, stimulating the gag reflex and resultant vomiting.
TABLE 4
During a convulsion, 3 spheres of concern
| AVOID MATERNAL INJURY |
| Insert padded tongue blade |
| Avoid inducing gag reflex |
| Elevate padded bedside rails |
| Use physical restraints as needed |
| MAINTAIN OXYGENATION TO MOTHER AND FETUS |
| Apply face mask with or without oxygen reservoir at 8–10 L/minute |
| Monitor oxygenation and metabolic status via |
| Transcutaneous pulse oximetry |
| Arterial blood gases (sodium bicarbonate administered accordingly) |
| Correct oxygenation and metabolic status before administering anesthetics that may depress myocardial function |
| MINIMIZE ASPIRATION |
| Place patient in lateral decubitus position (which also maximizes uterine blood flow and venous return) |
| Suction vomitus and oral secretions |
| Obtain chest x-ray after the convulsion is controlled to rule out aspiration |
Tips on supplemental oxygenation
Although the initial seizure lasts only a minute or 2, it is important to maintain oxygenation by giving supplemental oxygen via a face mask, with or without an oxygen reservoir, at 8 to 10 L per minute. This is important because hypoventilation and respiratory acidosis often occur.
Once the convulsion ends and the patient resumes breathing, oxygenation is rarely a problem. However, maternal hypoxemia and acidosis can develop in women with repetitive convulsions, aspiration pneumonia, pulmonary edema, or a combination of these factors. Thus, transcutaneous pulse oximetry is advisable to monitor oxygenation in eclamptic patients.
Arterial blood gas analysis is necessary if pulse oximetry shows abnormal oxygen saturation (ie, at or below 92%).
Strategy to prevent recurrence
Magnesium sulfate is the drug of choice to treat and prevent subsequent convulsions in women with eclampsia.1,2
Dosage. I give a loading dose of 6 g over 15 to 20 minutes, followed by a maintenance dose of 2 g per hour as a continuous intravenous solution.
Approximately 10% of eclamptic women have a second convulsion after receiving magnesium sulfate.1,2 When this occurs, I give another 2-g bolus intravenously over 3 to 5 minutes.
More rarely, a woman will continue to have convulsions while receiving adequate and therapeutic doses of magnesium sulfate.
I treat such patients with sodium amobarbital, 250 mg, intravenously over 3 to 5 minutes.
Monitor maternal magnesium levels
Plasma levels should be in the range of 4 to 8 mg/dL during treatment for eclampsia, and are determined by the volume of distribution and by renal excretion. Thus, it is important to monitor the patient for magnesium toxicity, particularly if she has renal dysfunction (serum creatinine of 1.2 mg/dL or above) or urine output below 100 mL in 4 hours. In these women, adjust the maintenance dose according to plasma levels.
Side effects of magnesium including flushing, a feeling of warmth, nausea and vomiting, double vision, and slurred speech (TABLE 5).
If magnesium toxicity is suspected, immediately discontinue the infusion and administer supplemental oxygen along with 10 mL of 10% calcium gluconate (1 g total) as an intravenous push slowly over 5 minutes.
If respiratory arrest occurs, prompt resuscitation—including intubation and assisted ventilation—is vital.
TABLE 5
Clinical manifestations of magnesium toxicity
Maternal plasma levels of 4 to 8 mg/dL are appropriate during treatment for eclampsia; higher levels signal toxicity
| IF THE MAGNESIUM LEVEL IS… | THE CLINICAL MANIFESTATION IS… |
|---|---|
| 8–12 mg/dL | Loss of patellar reflex |
| Double or blurred vision | |
| Headache and nausea | |
| 9–12 mg/dL | Feeling of warmth, flushing |
| 10–12 mg/dL | Somnolence |
| Slurred speech | |
| 15–17 mg/dL | Muscular paralysis |
| Respiratory arrest | |
| 30–35 mg/dL | Cardiac arrest |
