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 intramuscular every 24 hours for two doses, with
delivery 24 hours after the last dose) or dexamethasone (6 mg intramuscular 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
