Ob Anesthesia Module C, Part I

Front 1

What are the hypertensive disorders of pregnancy?

Back 1

Gestational HTN-b/p >140/90, with no proteinuria (after 20 weeks)
Preeclampsia
Eclampsia
Superimposed preeclampsia
Chronic HTN

Front 2

What is preeclampsia?

Back 2

Syndrome of pregnancy induced HTN, proteinuria, generalized edema, sustained SBP>140, 300mg or protein in 24 hr collection, S/S appear after 20weeks gestation, resolves 48 hours after delivery

Front 3

What causes preeclampsia?

Back 3

Occurs only in the prescence of placental tissue, endothelial cell dysfunction central to pathogenesis-pt. produces deficient levels of vasodilator prostacyclin & excessive levels of vasoconstrictor thromboxane, vasospasm central to physiology of preeclampsia; trophoblass (outermost layer of placenta) fail to implant into spiral arteries=hypoperfusion=endothial damage/vascular hyperreactivity=maternal HTN & decreased placental perfusion

Front 4

How does preeclampsia impact the patient'S CV & RESP SYSTEMS?

Back 4

CV: HTN d/t generalized vasoconstriction, increased SVR, hemoconcentration, hypoalbuminemia; Pulmonary: low colloid oncotic pressure d/t hypoproteinemia and increased vascular permeability, increasaed risk of pulmonary edema and difficult airway;

Front 5

How does preeclampsia impact the patient's CNS, Renal, Hepatic, Hematologic systems?

Back 5

CNS: vasospasm +/- cerebral edema can cause visual disturbance, H/A, hyperreflexia; Renal: decreased GFR, RBF, proteinuria; Hepatic: risk of hepatic hematoma, rupture; Hematologic: hemoconcentration, thrombocytopenia, increased fibrinolysis

Front 6

What causes the maternal HTN in preeclampsia?

Back 6

Placental ischemia leads to the release into maternal circulation of vasoactive substances (thromboxane, renin, angiotensin, aldosterone, catecholamines, and thromboplastin) which increase maternal B/P

Front 7

What is eclampsia?

Back 7

Seizures associated with pregnancy induced HTN; treat with magnesium sulfate

Front 8

What is HELLP syndrome?

Back 8

Hemolysis, Elevated Liver enzymes, Low Platelet count

Front 9

When does HELLP syndrome occur?

Back 9

Before the 36th week of gestation, dx is indication for delivery

Front 10

What are the signs of severe preeclampsia?

Back 10

Hypertension >160/110, oliguria <500ml/d, pulmonary edema, hepatic tenderness, proteniuria, systemic edema, CNS dysfunction, HELLP syndrome

Front 11

The most serious complications of pre-eclampsia are?

Back 11

Pulmonary edema, renal failure, airway obstruction, cerebral hemorrhage, DIC, cerebral edema

Front 12

What are the two leading causes of maternal death in preeclampia?

Back 12

Cerebral hemorrhage, pulmonary edema, (then renal failure, DIC, airway obstruction)

Front 13

How does preeclampsia effect circulation?

Back 13

Protein content is decreased, intravascular space is contracted, usually not under filled, associated vasoconstriction d/t increased renin, angiotensin, & aldosterone

Front 14

What is the impact of pre-eclampsia on the uteroplacental circulation/

Back 14

uterine vascular resistance increases d/t vasculitis=decreased uterine blood flow

Front 15

In the preeclamptic patient what is the best test to evaluate bleeding?

Back 15

PT/PTT, platelets, fibrinogen, & FSP

Front 16

Which drugs are used to control B/P in the preeclamptic patient?

Back 16

Hydralazine, SNP, Trimethaphan, NTG, Labetolol, Nifedipine, Methyldopa, diazoxide

Front 17

What are the concerns when giving SNP or NTG to preeclamptic patients?

Back 17

SNP can cause cyandie toxicity,
NTG can be unpredictable,
In patients with HTN & low PAOP, SNP or NTG can precipitate profound decrease in B/P

Front 18

Why is hydralazine used so commonly in preeclamptic patients?

Back 18

Hydralazine can reduce maternal B/P and increase uterine blood flow simultaneously

Front 19

Which anti-hypertensive techniques should be avoided in the preeclamptic patient?

Back 19

Esmolol should NOT be used, adverse fetal effects;
General or regional anesthetics should NOT be used to reduce the B/P in this population

Front 20

What is the drug of choice to control preeclampsia?

Back 20

Magnesium Sulfate

Front 21

What are the normal serum levels for Magnesium Sulfate?

Back 21

Norm: 1.4-2.0mEq/L
Therapeutic range for preeclampsia/eclampsia is 4-7mEq/L; (divide by 0.8 to convert mEq/L to mg/dl); Loading dose 4-6gm over 20min; gtt 2-3gm/hour

Front 22

In order of prgression, what are the signs of hypermangnesemia?

Back 22

Least-to-worst: decreased deep tendon reflex (DTR), ECG changes, somnolence, loss of DTR, heart block, respiratory arrest, cadiac arrest

Front 23

If the patellar reflex is absent in patients on Magnesium Sulfate what can happen to the patient?

Back 23

Heart block
Ventilatory failure
Cardiac arrest

Front 24

How does MgSO4 work as an anticonvulsant?

Back 24

increases the seizure threshold by decreasing the presynaptic releaseof acetylcholine and reducing the sensitivity of post synaptic receptors to Ach; can also act as NMDA receptor antagonist

Front 25

The patient shows signs of MgSO4 toxicity, should you give Ca+?

Back 25

IV Ca+ gluconate should be given only if supportive therapies are ineffective; it reverses magnesium toxicity but increases risk of seizures; supportive measures first (intubation)

Front 26

Does magnesium toxicity impact the neonate?

Back 26

Yes, it can cross the placenta, neonate can be somnolent, atonic, and need ventilation assistance

Front 27

What is the definitive treatment for preeclampsia?

Back 27

Delivery of fetus and placenta

Front 28

Considering pt. hx (preeclampsia)-which anesthetic technique is most appropriate?

Back 28

CLE, SAB, or GA can be used, CLE best choice

Front 29

When is GA appropriate for delivery of a preeclamptic?

Back 29

coagulopathy present, fetal distress,

Front 30

What issues complicate fluid management in preeclamptics?

Back 30

plasma volume may be decreased in preeclampsia-filling pressures maintained by increased capacitance, colloid oncotic pressure is reduced, capillary permeability is increased

Front 31

What induction agent should be AVOIDED in PIH patients?

Back 31

Ketamine

Front 32

How does Magnesium Sulfate interact with muscle relaxants?

Back 32

It increases sensitivity to both depolarizing & non-depolarizing

Front 33

How long should you continue MgSO4 after delivery?

Back 33

24-48hrs d/t risk of seizures remains