Case 55 - pre-eclampsia Flashcards

1
Q

What is classified as HTN during pregnancy? what is the difference betewen chronic htn, pre-eclampsia, eclampsia, gestational htn?

A

HTN

  • systolic BP > 140
  • diastolic BP > 90

chronic htn

  • htn before 20 weeks

gestational htn

  • htn manifests after 20 weeks with NO symptoms

pre-eclampsia

  • htn manifests after 20 weeks + proteinuria
  • mild vs severe pre-eclampsia

elcampsia

  • pre-eclampsia + seizures
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2
Q

what is the difference between mild vs severe pre-eclampsia?

A

Mild pre-eclampsia

  • systolic > 140 or diastolic > 90
  • protienuria > 0.3 mg over 24 hours

severe pre-eclampsia

  • systolic > 160 or diastolic > 110
  • proteinuria > 5 g over 24 hours
  • headache
  • epigastric pain
  • HELLP
  • renal failure
  • visual distubances
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3
Q

what is the pathophysiology behind pre-eclampsia?

A
  • abnormal implantation of placenta
  • leads to poor perfusion of uterus and placenta (uteroplacenta ischemia)
  • uteroplacenta ischemia results in inappropriate release of vasoactive mediators
  • imbalance between thromboxane and prostacyclin balance
    • increase thromobxane leads to vasoconstriction, platelet aggregration, and decrease uterine blood flow
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4
Q

what systemic changes occur with pre-eclampsia?

A

Overall

  • pre-eclampsia assoc with systemic vasospasm
  • assoc with inc aldosterone
    • sodium and water retention -> generalized edema

CNS

  • cerebral edema, cerebral vasospasm
  • seizures, blindness, n/v
  • cerebral hemorrhage - leading cause of death in pre-eclamptic pts

Pulm

  • difficult intubation 2/2 laryngeal and upper airway edema
  • pulm edema -> pulm capillary leak -> A-a gradient

CVS

  • HTN
  • LVH - > diastolic dysfunction
  • 3rd spacing -> relative hypovolemia

Renal

  • decrease RBF and GFR

Hepatic System

  • subscapsular hemorrhage
  • vasospasm of hepatic A -> decrease liver flow -> abnormal LFTs

Heme

  • HELLP
  • thrombocytopenia
  • DIC

uterolplacental

  • IUGR
  • placental abruption
  • premature labor
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5
Q

what is managemnt of pre-eclampsia?

A

control disease, prevent progression to eclampsia

  • bed rest
  • Left uterine displacement
  • coag studies, LFTs, Renal studies
  • constant monitor of fetal and materal well being
  • admin MgSo4
    • helps prevent eclampsia
    • therapeutic 4-8 mEq/L
  • definitive tx = delivery of fetus
    • do if fetal distress
    • do if mom becomes eclamptic or worsening pre-eclampsia
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6
Q

Why is MgSo4 used in pre-eclampsia, what are other properties seen with MgSo4?

A

MgSo4

  • first line therapy for prevention of eclampsia

Properties

  • CNS depressant
  • anticonvulsant
  • Muscle relaxation via NMJ
    • potentiates NMBDs
    • inhibit AcH releaes
    • decrease AcH receptor sensitivity at NMJ
  • vasodilator -> hypotension
  • uterine relaxation
  • crosses placenta -> neonatal depression, apnea, dec muscle tone
  • toxicity treated with Calcium
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7
Q

how much mgso4 do you give as loading dose, what infusion rate do you run, when do you see loss of DTR, resp arrest, cardiac arrest?

A

MgSo4 admin

  • loading dose 2-4g over 15 min
  • mainteance 1-3g /hr
  • monitor signs of toxicity:
    • EKG changes (widened QRS, prolong PR)
    • loss of DTR

Mg plasma levels and systemic effects (meq/l)

  • therapeutic = 4-8
  • EKG changes = 5-10
  • Loss of DTR = 10
  • Resp arrest = 15
  • cardiac arrest = 25
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8
Q

why is it important to control HTN in pre-eclamptic patients? What is your BP goal? what agents will you use?

A

Cerebral Hemorrhage

  • leading cause of death in pre-eclamptic pts
  • CONTROL BP to prevent this

BP goal

  • do not acutely decrease BP
    • may decrease uteroplacental flow
    • cerebral ischemia 2/2 right shift of autoreg curve
  • tx to w/i 20% of baseline

Agents (acute vs non-acute control)

Non-acute control

  • hydralazine - Most commonly used
  • labetolol
    • do not use in reactive airway dz

Acute Control

  • SNP -
    • risk of cyanide toxicity in neonate (SNP crosses placenta)
  • NTG - minimal effects on fetus
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9
Q

what benefits will an epidural provide for pre-eclamptic patients? Prior to placing an epidural, what important things do you need to look for, specifically for pre-eclamptic patients?

A

epidural benefits for pre-eclamptic patients

  • pain control
    • reduce hyperventilation -> better uteroplacental blood flow
    • decreaes catecholamine release -> better uteroplacental blood flow
  • avoid need for general anesthesia
    • avoid difficult intubation
    • avoid risk of maternal aspiratoin

considerations for epidural placement & pre-eclampsia

assess following before epidural placement:

1) diastolic < 110 mm Hg

2) intravascular repeltion

  • pre-eclamptic pts typically fluid-depleted (3rd spacing, proteinuria)

3) COAG STUDIES

  • risk for DIC
  • thrombocytopenia
  • HELLP
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10
Q

what would be your anesthetic plan for a pre-eclamptic patient undergoing elective c/s and emergent c/s?

A

Elective C/S

  • assuming coag studies normal & BP under control, neuraxial anesthesia = safest option
    • avoid difficult intubation
    • avoid maternal aspiratoin
    • avoid BP increase with laryngoscopy -> risk of cerebral hemorrhage

Emergent C/S

  • dose pre-existing epidural to surgical anes
  • no epidural, then General Anesthesia
    • less prepartory time

General Anes

  • Control BP before induction even if emergent c/s
    • decrease symp stim with laryngoscopy -> risk of cerebral hemorrhage
  • anes machine set up with emergent drugs, emergent airway equip, suction, various blades, handles, ETTs
  • GET HELP!
  • RSI&I
    • pre-oxygentate
    • glidescope, suction, emergent meds on stand by
    • cricoid pressure
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11
Q

do you stop MgSo4 after delivery of fetus to help with uterine relaxation, do you stop after completion of c/s?

A

MGSo4 should be continued for at least 24 hrs after surgery

patient still at risk for eclampsia post-partum

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