Anesthetic Management of the Patient with Preeclampsia

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Anesthetic Management of the Patient with
Preeclampsia

• Dmitry Portnoy, MD
• Anesthesiology Department

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MATERNAL MORTALITY IN PREGNANCY IN THE UNITED
STATES, 1980-1985
Adapted from the US Maternal mortality
Surveillance, 1980-1985. MMWR CDC Surveillance
Summary, 1988.
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Classification of Hypertensive Disease in
Pregnancy(Australian Society for the Study of
Hypertension in Pregnancy, 1999)
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Risk Factors and Mechanisms of Preeclampsia

• Risk of preeclampsia up to 8 of all
  pregnancies
• Factors implicated in increased risk of
  developing preeclampsia
• Genetic determination, familial history
• Chronic HTN, DM, chronic renal disease, LSE,
  sickle cell
• Twin gestation, nulliparity, maternal age over
  40, adolescents
• Pathogenesis of preeclampsia is poorly understood
• multisystem abnormalities - only in the presence
  of placental tissue
• generalized endothelial cell disorder
• excessive immunologic reaction
• Triad of physiological derangements
• Intense vasospasm
  endothelium, platelets, trophoblasts
• Local or disseminated intravascular coagulation
• Plasma volume contraction

disruption
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FACTORS THAT DIFFERENTIATE MILD FROM SEVERE
PREECLAMPSIA
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Severe Preeclampsia Diagnostic Criteria

• Two or more of the following signs
• Systolic blood pressure of 160 mmHg or diastolic
  pressure of 110 mmHg recorded six hours apart
  with the patient at bed rest
• Proteinuria, 5g/24 hours or 3 to 4 protein on
  dipstick
• Oliguria, urine output less than 400 mL/24 hours,
  or less than 30 mL/hour for two consecutive hours
• Cerebral or visual disturbances, including eye
  changes
• Pulmonary edema
• Epigastric pain
• Evidence of hemolysis, abnormal results from
  liver function tests, and/or thrombocytopenia
• Generalized convulsions and no history of seizure
  disorder

Adapted from Stone JL, et al. Risk factors for
severe preeclampsia. Obstet Gynecol
199483357-361
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Organ System Derangements in Eclampsia
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Principles of Treatment of Preeclampsia

• Delivery - definitive treatment (except for
  atypical)
• Antihypertensive drug therapy
• Bed rest, non-stimulating environment
• Aspirin, Calcium supplementation, volume expansion

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Magnesium Sulfate Therapy

• Potentiation of neuromuscular blockade (for all
  relaxants)
• Weakness
• Respiratory depression
• Cardiovascular effects
• ECG changes
• Cardiac arrest
• Hypotension
• Decreased uterine tone
• Excessive blood loss
• Neonatal effects

• Magnesium Toxicity
•  
• Loss of patellar reflex 812 mg/dl
• Warmth, flushing 912 mg/dl
• Somnolence 1012 mg/dl
• Slurred speech 1012 mg/dl
• Muscular paralysis 1517 mg/dl
• Respiratory difficulty 1517 mg/dl
• Cardiac arrest 3035 mg/dl
• Theraputic range 4-8 mg/dl

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INDICATIONS FOR DELIVERY OF THE FETUS IN SEVERE
PREECLAMPSIA
Modified from Gallery EDM Hypertension in
pregnancy. Practical management recommendations.
Drugs 1995494561.
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Pre-anesthetic Evaluation

• Assessment of target organ-system involvement
• CV HTN control, LV function, intravascular
  depletion
• Renal degree of oliguria, creatinine level
• Liver LFTs, signs of liver capsule streching
• Coagulation profile platelet count, PT, PTT
• Airway examination degree of laryngeal edema
• Anesthetic risk factors
• Poorly controlled hypertension
• gt2 urinary protein, elevated serum uric acid
• Thrombocytopenia less than 75,000
• Central vascular volume depletion
• Association with chronic HTN and IDDM

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Invasive Monitoring

• Arterial catheter
• Sustained diastolic blood pressure greater than
  90 mm Hg
• Use of parenteral vasodilaters (NTP, NTG)
• Induction of anesthesia with potential rapid BP
  fluctuations
• Inability to obtain accurate BP by cuff
• Need for frequent sampling
• Pulmonary artery catheter
• Severe HTN unresponsive to conventional treatment
• Severe pulmonary edema
• Persistent oliguria unresponsive to fluid
  challenge

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Regional Anesthesia for Preeclamptic Patient

• Advantages of epidural anesthesia
• Blunts hormonal and hemodynamic responses
• Provides better hemodynamic stability
• Increases renal and uteroplacental blood flow
• Decrease potential for seizures
• Spinal anesthesia
• Growing evidence of safety in preeclampsia
• Less hemodynamic stability (?)
• Less potential for hematoma
• Combined spinal-epidural

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Thrombocytopenia and Epidural Block
?

• Safe lower limit for platelet count before
  epidural
• Retrospective analysis of 2929 parturients
  (Rasmus, 1989)
• 14 with platelet count 18,000 90,000 received
  neuraxial block
• None had sequelae of spinal hematoma
• No spinal/epidural hematomas in parturients
  reported
• Low-dose aspirin and neuraxial block apparently
  safe
• Bleeding time questionable indicator of risk of
  RA
• Recommendations
• Patient history, signs of bleeding, test tube
  clot formation, ACT
• Modification of technique that decreased the risk
  of bleeding

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General Anesthesia for Preeclamptic Patient

• Airway edema
• Attention to hoarseness, high pitched or
  stridorous voice
• Small ETT (5-6 mm)
• Hypertensive response
• Induction, intubation and extubation
• HTN and tachycardia can lead to increased ICP
• Interaction of anesthetic agents with magnesium
  sulfate

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HELLP Syndrome

• H
• E
• L
• L
• P
• Occurs in 4-12 of severe PIH patients
• Reported perinatal mortality 7.7- 60
• Maternal mortality 3.5- 24.2.

emolisis
elevated
iver
ow
latelets
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Eclampsia

• From Gr., a fancied perception of flashes of
  light
• Occurrence of a seizure that is not attributable
  to other causes in a preeclamptic patient
• Steps in managing an eclamptic convulsion
• Maintain adequate oxygenation
• Prevent maternal injury during the convulsion
• Minimize the risk of aspiration
• Give adequate magnesium sulfate to control the
  convulsions
• Maternal acidemia should be corrected
• Do not attempt to shorten or abolish the initial
  convulsion
• Avoid polypharmacy

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Conclusion

• Preeclampsia is fairly common multisystem
  disorder
• Associated with high maternal and perinatal MM.
  (Mortality in obstetric patient can be 200!)
• Important steps in anesthesia management
• Close communication with obstetrical colleagues
• Early and detailed preoperative assessment and
  plan
• Meticulous monitoring, including invasive
  monitors if indicated
• Utilization of advantages of RA when appropriate
• Close postoperative follow-up