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management of hypertensive disorder of pregnancy from william's obstetrics
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MANAGEMENT• Basic management objectives for any pregnancy
complicated by preeclampsia:
1. Termination of pregnancy with the least possible trauma to mother and fetus
2. Birth of an infant who subsequently thrives
3. Complete restoration of health to the mother
“Termination of pregnancy is the only cure for preeclampsia”
• Headache, visual disturbances, or epigastric pain is indicative that convulsions may be imminent, and oliguria is another ominous sign.
Antihypertensive Therapy for Mild to Moderate Hypertension
Delayed Delivery• “conservative” or “expectant”• Aim of improving neonatal outcome without
compromising maternal safety
Expectant Management of Preterm Severe Preeclampsia1. Glucocorticoid Administration
• Betamethasone• 2 doses of 12mg IM, 24 hrs apart
• Dexamethasone• 4 doses of 6mg IM, 12 hrs apart
2. Delivery in 48hrs
Glucocorticoids for Lung Maturation• No effect in maternal hypertension• Decrease incidence of respiratory distress• Improved fetal survival
Eclampsia • Preeclampsia complicated by generalized tonic –
clonic convulsions• Fatal: coma w/o convulsions• Once it has enused, there is increased risk to
mother & fetus• Prognosis is always serious
Eclampsia Major Complications• Abruption • Neurological deficits • Aspiration pneumonia • Pulmonary edema • Cardiopulmonary arrest • Acute renal failure • Maternal death
Eclampsia• Precedes the onset of eclamptic convulsions• Designated as antepartum, intrapartum, or
postpartum. • Most common in the last trimester • Becomes increasingly frequent as term approaches
Imminent Signs of Convulsion• Severe headache• Visual disturbances• Epigastric pain
Eclampsia
Immediate Management of Seizure• Eclamptic seizures may be violent and the woman
must be protected especially her airway• Status epilepticus• Require deep sedation and even general anesthesia to
obviate anoxic anencephalopathy
Management• Control of convulsions (MgSO4)• IV antihypertensive drugs• Avoidance of diuretics and limitation of IVF• Delivery – eclampsia mandates delivery regardless
of AOG.• Vaginal Delivery
• Inducible cervix• No fetal distress
• Caesarean section
Magnesium Sulfate to Control Convulsions
Magnesium Sulfate to Control Convulsions• When magnesium sulfate is given to arrest
eclamptic seizures, 10 to 15 percent of women will have a subsequent convulsion. • If so, an additional 2-g dose of magnesium sulfate
in a 20-percent solution is slowly administered intravenously.
Magnesium Sulfate:Mechanism of Action• Anticonvulsant• Reduced presynaptic release of the neurotransmitter
glutamate• Blockade of glutamatergic N-methyl-D-aspartate
(NMDA) receptors• Potentiation of adenosine action• Improved mitochondrial calcium buffering• Blockage of calcium entry via voltage-gated channels
Magnesium Sulfate:Pharmacology and Toxicology• Eclamptic convulsions are almost always prevented or
arrested by plasma magnesium levels maintained at 4 to 7 meq/L, 4.8 to 8.4 mg/dL, or 2.0 to 3.5 mmol/L
• Patellar reflexes disappear when the plasma magnesium level reaches 10 meq/L—about 12 mg/dL—presumably because of a curariform action.
• This sign serves to warn of impending magnesium toxicity. When plasma levels rise above 10 meq/L, breathing becomes weakened
Magnesium Sulfate:Pharmacology and Toxicology• 12 meq/L or more respiratory paralysis and
respiratory arrest
• calcium gluconate or calcium chloride 1 g/IV• antidote to magnesium sulfate toxicity
• For severe respiratory depression and arrest• prompt tracheal intubation and mechanical ventilation
are lifesaving
Magnesium Sulfate:Pharmacology and Toxicology• Renal function is estimated by measuring plasma
creatinine
• Whenever plasma creatinine levels are > 1.0 mg/mL, serum magnesium levels are used to adjust the infusion rate
Magnesium Sulfate• Uterine effects - depress myometrial contractility• serum levels of at least 8 to 10 meq/L are necessary to
inhibit uterine contractions
• Fetal Effects – decreased variability in NST• neuroprotective
Severe Hypertension• Dangerous hypertension can cause cerebrovascular
hemorrhage and hypertensive encephalopathy, andit can trigger eclampticconvulsions in women with preeclampsia.
Management:Severe Hypertension• ANTIHYPERTENSIVE AGENTS
1. HYDRALAZINE• administered intravenously with
• 5-mg initial dose• followed by 5- to 10-mg doses at 15- to 20-minute intervals until
a satisfactory response is achieved• The target response antepartum or intrapartum is a decrease in
diastolic blood pressure to 90 to 100 mm Hg, but not lower• onset of action can be as rapid as 10 minutes
Management:Severe Hypertension• ANTIHYPERTENSIVE AGENTS
2. LABETALOL• α 1 and non selective β blocker used in the US• starting with a 20-mg intravenous bolus• If not effective within 10 minutes, this is followed by 40 mg,
then 80 mg every 10 minutes but not to exceed a 220-mg total dose per episode treated
Management:Severe Hypertension• ANTIHYPERTENSIVE AGENTS
3. NIFEDIPINE• calcium-channel blocking agent• 10-mg initial oral dose to be repeated in 30 minutes if
necessary• given sublingually is no longer recommended
Management:Severe Hypertension• Other Antihypertensive Agents
a. verapamilb. nimodipinec. nitroprusside or nitroglycerine
Management:Severe Hypertension• DIURETICS• before delivery, diuretics are not used to lower blood
pressure
• FLUID THERAPY• Lactated Ringer solution is administered routinely at the
rate of 60 mL to no more than 125 mL per hour unless there is unusual fluid loss from vomiting, diarrhea, or diaphoresis, or more likely, there is excessive blood loss with delivery
Management:Severe Hypertension• PLASMA VOLUME EXPANSION• preeclampsia syndrome is associated with
hemoconcentration directly proportional to syndrome severity, attempts to expand blood volume seem reasonable, at least intuitively
• fluids, starch polymers, albumin concentrates, or combinations
Management:Severe Hypertension• DELIVERY• prevention of blood loss• analgesia and anesthesia – epidural blockade; ET
anesthesia
• End. • Thank you