Pathophysiology of Obstetric Disorders Flashcards
(58 cards)
How is chronic hypertension defined in the obstetric patient?
Occurs before 20 weeks gestation
Does not return to normal after delivery
What is gestational hypertension?
Develops after 20 weeks gestation
Proteinuria does not occur
Return to normotensive state after delivery
What is preeclampsia?
Hypertension that develops after 20 weeks gestation
Proteinuria typically present
If proteinuria is not present, any of the following conditions are indicative of preeclampsia:
Persistent RUQ or epigastric pain
Persistent CNS or visual symptoms
Fetal growth restriction
Thrombocytopenia
Elevated serum liver enzymes
What is eclampsia?
The mother with preeclampsia develops seizures
How does healthy placental implantation compare to that of a preeclamptic patient?
Healthy placenta produces equal amounts of thromboxane and prostacyclin
Preeclamptic patient’s placenta produces up to seven times more thromboxane than prostacyclin. It also produces a variety of cytokines.
How do increased levels of thromboxane affect the placenta?
Thromboxane increases:
Platelet aggregation
Vasoconstriction
Uterine activity
and decreases:
Uteroplacental bloodflow
What are major potential consequences of preeclampsia?
Proteinuria
DIC
Intracranial hemorrhage/ cerebral edema
Heart failure/ pulmonary edema
What are the blood pressure parameters for mild preeclampsia?
<160/ <110 mmHg
What are the blood pressure parameters for severe preeclampsia?
> = 160/ >= 110 mmHg
What causes the hypertension seen in preeclampsia?
Vasoconstriction due to thromboxane
What systemic symptoms may be present in severe preeclampsia that are not present in mild preeclampsia?
Decreased urine output
Pulmonary edema
Cyanosis
Headache
Visual impairment
Epigastric pain
HELLP syndrome
What role does thromboxane play in preeclampsia?
Increases vasoconstriction = increases blood pressure
How may preeclampsia affect renal function?
Glomerular capillary endothelial destruction and renal edema may result in proteinuria and decreased urine output
What is the pathophysiology of the generalized edema that may be present in preeclampsia and the pulmonary edema that may occur in severe preeclampsia?
Decreased oncotic pressure
Increased vascular permeability
What is the definitive treatment of preeclampsia and eclampsia?
Delivery of the fetus and placent
At what blood pressure should the preeclamptic parturient receive pharmacologic treatment?
160/110 mmHg
What is the primary reason for treating blood pressure in preeclampsia?
Prevent cerebrovascular accident, myocardial ischemia, and placental abruption
What is the pharmacologic treatment for acute hypertension in pregnancy?
Labetalol 20 mg IV then 40-80 mg q 10 min up to a max dose of 220 mg
Hydralazine 5mg IV q 20 min up to a max dose of 20 mg
Nifedipine 10 mg PO q 20 min up to a max dose of 50 mg
Nicardipine infusion started at 5 mg/hr and titrated by 2.5 mg/hr q 5 min up to a max of 15 mg/hr
How long is the patient at risk for complication related to severe preeclampsia?
Up to 4 weeks into the postpartum period
When is the patient at highest risk for pulmonary hypertension and stroke?
In the postpartum period
How does neuraxial anesthesia impact the preeclamptic patient?
Assists with blood pressure control > better uteroplacental perfusion
What are some anesthetic considerations for the preeclamptic patient?
Rule out thrombocytopenia prior to a neuraxial block
More likely to be a difficult intubation d/t airway swelling
Beta blockers, remifentanil, and Mg++ blunt the hemodynamic response to laryngoscopy
Exaggerated response to sympathomimetics and methergine
What are anesthetic considerations in the preeclamptic patient receiving Mg++?
Increased sensitivity to neuromuscular blockers
Increased risk for postpartum hemorrhage
What is the seizure prophylaxis regimen for eclamptic patients?
Mg++:
Loading dose of 4 g over 10 minutes
Infusion 1-2 g/hr
