Management of Severe Preeclampsia

The definitive treatment of preeclampsia is the delivery of the placenta. The timing of delivery depends on gestational age, the severity of preeclampsia, and maternal and fetal conditions.

Another important aspect in the management of severe preeclampsia is the control of hypertension.

A. BP control

1.       Arterial pressure greater than 160/110 mmHg in preeclampsia can increase the risk of complications, and it should be controlled.

2.       BP control should only be done in the ICU, preferably with arterial line monitoring.

3.       BP control should also be done along with fetal monitoring. Avoid sudden falls in BP as it can result in fetal distress.

4.       The goal of BP control is a 15–25% reduction in the mean arterial pressure, and a reduction of pressure to baseline BP levels (<140/90 mmHg) rather than normal BP, should be avoided as it may compromise placental perfusion.

5.       Drugs

a)       Labetalol (IV 20 mg) can be given initially, followed by doubling the dose every 10 min to a cumulative dose of 300 mg. This drug can result in severe bradycardia. A continuous infusion of labetalol at a rate of 0.5–2 mg/min can also be used.

b)      Hydralazine (5–10 mg) can be given every 20 min (maximum of 40 mg) until BP is controlled.

c)       Nifedipine or nicardipine can be given (sudden precipitous decrease in BP or tachycardia can occur).

d)      Intravenous nitroglycerin (10–100 mg/min) or sodium nitroprusside (2–8 mg/min) can be given. Prolonged use of nitroglycerin may lead to methemoglobinemia. Cyanide toxicity in the mother and fetus may occur with sodium nitroprusside, limiting its use to less than 4 h and only as a last resort.

B. Seizure control

1.       The initial management of eclampsia includes airway, breathing, and circulation.

2.       Seizure prophylaxis is given intrapartum or postpartum with magnesium sulfate in cases of severe preeclampsia.

3.       The initial bolus of magnesium (4 g over 5–15 min) is followed by an infusion of 1–2 g/h maintained for 24 hrs.

4.       The mechanism of action of magnesium is unknown, but magnesium suppresses excitatory neurotransmitter release by replacing calcium at nerve endings.

a)       Monitor toxicity—loss of deep tendon reflexes; loss of patellar reflex occurs when the plasma magnesium level is more than 10 mg%. Look for respiratory muscle weakness.

b)      Magnesium has a relatively narrow therapeutic range, and target magnesium serum concentrations are 5–8 mg/dL.

c)       Infusion dose should be reduced in cases of renal dysfunction. Serum magnesium levels should be monitored every 4–6 hours and whenever a seizure occurs, or signs of toxicity are present, as per Table

Clinical manifestations related to the serum concentration of magnesium
Serum magnesium levels (mg/dL)	Effects
5–8	Therapeutic
8–12	Loss of deep tendon reflexes
12–16	Muscular paralysis and respiratory difficulties
>17	Conduction disturbances
>25	Cardiac arrest

 

d)       In recurrent seizures, an additional 2–4 g of magnesium sulfate can be given over 5 mins concurrently with the magnesium sulfate infusion.

e)      Calcium gluconate 15–30 mL of a 10% solution, administered intravenously over 2–5 minutes, is given to women with cardiac arrest or severe cardiac toxicity related to magnesium toxicity.

f)        If seizures are not controlled by a repeat magnesium bolus, then diazepam or lorazepam can be administered.

g)       Discontinue magnesium sulfate 24 h after delivery.

 

 

C. Fluid management

1.       Despite peripheral edema, patients with preeclampsia are volume-depleted with high peripheral vascular resistance. Diuretics should be avoided.

2.       Aggressive volume resuscitation, on the other hand, may lead to pulmonary edema, which is a common cause of maternal morbidity and mortality. Because volume expansion has no demonstrated benefit, patients should be fluid-restricted, when possible, at least until the period of postpartum diuresis.

3.       Central venous or pulmonary artery pressure monitoring or other hemodynamic monitoring modalities may be indicated in critical cases.

4.       Careful measurement of fluid input and output is advisable, particularly in the immediate postpartum period.

5.       D. Decide the timing and type of delivery

6.       As maternal morbidity is very high with severe preeclampsia, prompt delivery is indicated regardless of gestational age.

7.       Women with severe preeclampsia who are managed expectantly (non-severe disease) must be delivered under the following circumstances:

a.       Severe hypertension develops refractoriness to treatment

b.       Non-reassuring fetal heart status

c.       Uncontrollable BP

d.       Oligohydramnios, with amniotic fluid index of less than 5 cm.

e.       Severe intrauterine growth restriction.

f.        Oliguria (<500 mL/24 h)

g.       Serum creatinine level of at least 1.5 mg/dL

h.       Pulmonary edema

i.         Shortness of breath or chest pain with pulse oximetry of <94% on room air

j.         Headache that is persistent and severe Right upper quadrant tenderness with deteriorating liver function test

k.       Development of HELLP syndrome

l.         Severe hypertension after 34 weeks when their blood pressure has been controlled and a course of corticosteroids has been completed (if appropriate).

m.     Offer birth to women with pre-eclampsia before 34 weeks only after discussion with neonatal and anesthetic teams and a course of corticosteroids has been given.

n.       Preeclampsia is not an indication for caesarian delivery and many patients can have a normal vaginal delivery.

Watch for complications

1.       Abruptio placentae

2.       Disseminated intravascular coagulopathy (DIC)

3.       Renal insufficiency and acute renal failure

4.       HELLP syndrome

5.       Eclampsia

6.       Cerebral hemorrhage

7.       Fetal changes—intrauterine growth restriction, abruptio placentae, oligohydramnios

8.        Intrauterine fetal death

Managing Complications

HELLP syndrome

1.       HELLP syndrome can complicate 4–12% of patients with severe preeclampsia.

2.       Signs and symptoms are right upper quadrant or epigastric pain, nausea and vomiting, malaise, and nonspecific viral-like symptoms. Physical examination findings include right upper quadrant or epigastrium tenderness and generalized edema.

Tennessee classification:

1.       Hemolysis: established by the presence of at least two of the following:

2.       Peripheral smear showing schistocytes and burr cells

3.       Serum bilirubin ≥1.2 mg/dL

4.       Low serum haptoglobin (≤25 mg/dL) or LDH ≥2 times the upper level of normal

5.       Severe anemia unrelated to blood loss, Elevated liver enzymes Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) ≥2 times the upper level of normal, Low platelets: <100,000 cells/microL

 

Delivery is the definitive treatment for HELLP syndrome.

a.       Delivery is indicated for women with HELLP syndrome at greater than 34 weeks of gestation.

b.       During labor and for 24-h postpartum, patients should receive intravenous magnesium sulfate for seizure prophylaxis.

c.       If gestation is less than 34 weeks, delivery may be delayed for 48 hours to administer a steroid course of either betamethasone (12 mg intramuscularly every 24 hours for two doses, with delivery 24 hours after the last dose) or dexamethasone (6 mg intramuscularly every 12 hours for 2 days).

d.       Platelets are generally transfused when the platelet count is less than 20,000/mm. For cesarean delivery or with any significant bleeding, platelets should be transfused if the platelet count is less than 50,000/mm3.

Acute Pulmonary Edema

1.       Management is similar to non-pregnant patients.

2.       Intravenous furosemide (bolus 20–40 mg over 2 min) is used to promote diuresis. Repeated doses of 40–60 mg is given after 30 min or infusion if there is an inadequate diuretic response (maximum dose 120 mg/h).

3.       Careful fetal monitoring, fluid restriction, and strict fluid balance and positioning