Preeclampsia

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Preeclampsia

• December 14, 2006
• R3???

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Definition

• Hypertension occurring after 20 weeks gestation
  SBPgt140mmHg, DBPgt90mmHg
• Proteinuria gt300mg/24h
• Edema
• 8 of all pregnancies

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Severe Preeclampsia

• SBP 160mmHg, DBP 110mmHg
• Proteinuria 5g/24hr
• Urine output lt 500ml/24hr
• Headache or visual disturbance
• Pulmonary edema
• Epigastric or RUQ abdominal pain
• HELLP
• Platelet count lt 100000/mm3

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Risk Factors

• Homozygous angiotensin T235
• Chronic renal disease
• Antiphospholipid syndrome
• Chronic hypertension
• Family history of preeclampsia
• Multiple gestation
• Nulliparity
• Maternal age gt 40 years
• Diabetes
• African American race

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Pathogenesis

• Immunologic factors
• Genetic factors
• Endothelial factors
• Platelet factors
• Calcium
• Coagulation factors
• Fatty acid metabolism

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The Pathologic Alternations

• Cardiovascular BP, blood volume
• Hemodynamic
• Hematologic hypercoagulable state( table 38-1)
• Renal decreased GFR, proteinuria, oliguria,
  hyperuricemia
• Endocrine decreased plasma renin, suppression of
  renin-angiotensin-aldosterone system
• Respiratory pharyngolaryngeal edema, pulmonary
  edema
• Hepatic serum transaminase levels increase,
  epigastric or subcostal pain, liver rupture
• Neurologic severe headache, visual disturbance,
  CNS hyperexcitability, hyperreflexia, seizure
• Uteroplacental perfusion intrauterine growth
  retardation

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Hypercoagulable State
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Hemodynamic Changes

• Three subsets
• Hyperdynamic high cardiac output, normal to
  increased SVR, normal or slightly decreased blood
  volume and filling pressures
• High SVR, normal cardiac output, lower filling
  pressures
• Markedly increased SVR, reduced blood volume,
  decreased LV function

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Complications

• Maternal
• DIC
• CHF with pulmonary edema
• Placental abruption
• PPH
• ARF
• Hepatic rupture
• CVA ICH- the leading cause of maternal death
• Septic shock

• Fetal
• Prematurity with respiratory distress
• IUGR
• Oligohydramnios
• ICH
• Small for gestational age
• Aspiration of meconium
• Leading cause of intrauterine M/M Uteroplacental
  insufficiency by placental infarcts, placental
  abruption, and chorioamnioitis

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Preoperative Evaluation and Preparation

• Laboratory studies
• CBC
• Platelet
• Coagulation assay
• Electrolytes
• BUN/ Cre, UA
• Liver function tests
• Urinalysis

• Monitors
• NIBP
• Maternal ventilation
• Hourly DTR
• Muscle strength
• MgSO4 levels
• Urine output
• Uterine contraction monitor
• Fetal heart rate
• A line
• CVP or PA catheter

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Immediate Delivery

• Severe hypertension that persists after 24 to 48
  hours
• Progressive thrombocytopenia
• Liver dysfunction
• Progressive renal dysfunction (including severe
  oliguria)
• Premonitory signs of eclampsia
• Evidence of fetal jeopardy

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Obstetric Management

• Goal to stabilize the mother and deliver the
  fetus and placenta
• Improve intravascular volume
• Seizure prophylaxis
• BP control

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Antihypertensives
Hydralazine Labetalol
Mode of action Vasodilator a-andß- blocker
Speed of onset Gradual Quick
Dose 5-10 mg IV slowly 10-20 mg IV slowly
Interval Repeat after 20 min Titrate to effect
Infusion rate 2-20 mg/hr 20-160 mg/hr
Effect on heart rate Compensatory tachycardia No effect
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Antihypertensives

• Nitroglycerin
• Sodium nitroprusside cyanide toxicity
• Nifedipine facial flushing, headache, tachycardia

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Magnesium Sulfate

• Actions
• CNS depressant and anticonvulsant
• Inhibit the release of Ach at the neuromuscular
  junction, decrease the sensitivity of the motor
  endplate to Ach, decrease muscle membrane
  excitability
• Decrease uterine hyperactivity improve uterine
  blood flow
• Mild vasodilator

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Magnesium Sulfate

• Initial bolus of 4-6 g over 20 mins
• Infusion of 1-2 g/hr
• Monitor urine output, respiratory rate, patellar
  tendon reflexes, serum MgSO4 concentration(4-6
  mEq/L)
• Loss of DTR, prolonged P-Q intervals, widening
  QRS complexes, respiratory arrest, asystole

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Treatment of Eclampsia

• Stop the convulsions
• Establish an airway
• Maintain ventilation and oxygenation
• Maintain circulation
• Administer MgSO4
• Treat hypertension
• Deliver the baby expeditiously

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Intraoperative Management

• Choice of analgesia/anesthesia
• Spinal anesthesia
• General anesthesia
• -MgSO4 potentiates depolarizing and
  nondepolarizing muscle relaxants
• -Continue MgSO4 administeration
• -Consider A line before induction in patients
  with severe preeclampsia
• -Severe hypertension during intubation can
  increase maternal ICP and risks of CVA

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Postoperative Management

• Adequate analgesia
• Maintain strict intake/output for at least 24
  hours postpartum or until evidence of diuresis
• Continue magnesium sulfate for at least 24 hours
  postpartum or until evidence of diuresis
• Maintain hemodynamic control

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Thanks for Attentions!!