Term
| what is the leading cause of maternal death? |
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Definition
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Term
| what happens to blood volume in pregnancy? how? |
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Definition
| from wk 6-12, blood volume increases 30-50%. chorionic somatomammotropin is released from the placenta, which acts as an estrogen in stimulating angiotensin I, which is cleaved to angiotensin II (potent vasoconstrictor), which stimulates aldosterone which resorbs Na+, causing resorption of water - increasing blood volume. |
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Term
| what happens to the hematocrit in pregnancy as the volume increases? how does this affect the cardiac output? |
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Definition
| the hematocrit falls in pregnancy. but since the plasma volume increases in pregnancy, the resultant oxygen deprivation will increase the heart rate. since heart rate and stroke volume are increased, cardiac output will also increase (SV x HR = CO). in pregnancy, cardiac output is increased from 4.5 L/min to 6.5 L/min |
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Term
| why does stroke volume in pregnancy decrease later in pregnancy? how does this affect HR? |
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Definition
| the IVC becomes compressed by the uterus, decreasing R heart filling, which causes the HR to increase even more it compensate. |
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Term
| how is blood pressure calculated? |
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Definition
| BP = SVR (systemic vascular resistance) x CO. and since CO = SV x HR, then *BP = SVR x HR X SV. |
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Term
| what affects blood pressure in pregnancy? |
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Definition
| BP remains almost to pre-pregnant levels - except for a tendency to fall during midtrimester as systemic vascular/peripheral resistance falls. this is due to a large *arteriovenous shunting of the placental bed and physiologic *vasodilation secondary to circulating progesterone - even though CO has increased. BP does slowly rise over the 38 wk period though as the fetus develops it's own internal resistance and chips away at the low pregnant-state SVR. |
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Term
| what happens to HR over pregnancy? (*know this*) |
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Definition
| it increases steadily from wk 5 on |
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Term
| what happens to SVR over pregnancy? (*know this*) |
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Definition
| as the placenta grows, SVR will drop - but around wk 38 the fetus provides some of its own resistance, raising the SVR slightly towards the end. |
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Term
| what is the difference between systolic and diastolic pressure? (*know this*) |
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Definition
| systolic pressure is like if you turn on a hose and put your hand over the end - the force that hits you (vertical pressure) is systolic pressure. diastolic pressure is if you capped the end then wrapped your hands around it - the pressure pushing out (transverse vertical) is like diastolic pressure. |
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Term
| what happens to systolic/diastolic pressure over pregnancy? (*know this*) |
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Definition
| both drop b/c of placental shunting then slightly increase at the end |
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Term
| what happens to stroke volume over pregnancy? (*know this*) |
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Definition
| this increases until about 32 weeks when the IVC becomes compressed, which causes it to fall slightly |
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Term
| what happens to CO over pregnancy? (*know this*) |
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Definition
| CO continually increases over pregnancy |
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Term
| how does the fact that the hematocrit falls during pregnancy affect colloid oncotic pressure? what is the result of this? |
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Definition
| the fall in hematocrit causes a decrease in oncotic pressure, which increases hydrostatic pressure - allowing fluid to leak into the interstitium = mild edema. |
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Term
| what are normal physiologic changes in pregnancy which can mimic symptoms of cardiac disease? |
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Definition
| tired, dyspneic, orthopnic, syncope, light-headedness, , peripheral edema, hyperventilation, distended neck veins with prominent A and V waves, brisk/diffuse/displaced left ventricular impulse, palpable right ventricular impulse, increased S1 intensity, persistent splitting of S2, cervical venous hum, mammary souffle |
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Term
| what are the 3 main cardiovascular factors for maternal mortality? |
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Definition
| 1) *L ventricular systolic dysfunction/ejection fraction <.5* (so that when CO increases as it normally does, the heart fails) 2) *cyanosis (pulse ox <90%) 3) *L heart obstruction (like aortic stenosis) |
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Term
| how can you tell if a pt has L ventricular dysfunction? |
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Definition
| find the maximal point of intensity on the 5th intercostal space of the midclavicular line. it should be the same size as a normal finger pad, but w/L ventricular impairment this impulse will be huge (3-4 finger pads wide). there will also be a 3rd heart sound. |
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Term
| what kinds of cardiac disease carry <1% risk of maternal mortality in pregnancy? |
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Definition
| atrial septal defect, ventricular septal defect, patent ductus arteriosus, pulmonary/tricuspid valve disease, corrected tetralogy of fallot, and bioprosthetic valve. |
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Term
| what kinds of cardiac disease carry a 25-50% risk of maternal mortality w/pregnancy? |
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Definition
| aortic stenosis, previous MI (L ventricular function), primary pulmonary HTN, coarctation of the aorta, and peripartum cardiomyopathy (gross dilatation of all 4 ventricular chambers that occurs anywhere from the 3rd month of pregnancy to 6 months post delivery: idiopathic) - all of which cause L heart obstruction. |
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Term
| when in a code situation, where should you feel to determine if they are still alive? |
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Definition
| the femoral pulse. also: learn to intubate a pt. |
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Term
| what characterizes proper drug administration in pregnancy? |
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Definition
| don't have the pt on any drugs unless you have to, if you do: category A: universally safe (multivitamin), category B: presumed no evidence of risk (fish oil), category C: benefits may justify the potential risk - but need to articulate a good reason (diuretic), category D: unsafe (ACE inhibitors), category X: absolutely contraindicated (retinoic acid) |
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Term
| what should you do any time a pregnant pt may need to go on a drug? |
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Definition
| look it up every time (b/c drugs change classifications) |
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Term
| what characterizes anticoagulation therapy in pregnancy? |
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Definition
| no strategy is safe for both mother and fetus. warfarin causes teratogenic effects and intracranial bleeding. heparin doesn’t cross placenta and has no teratogenic effects but causes thrombocytopenia in mother, which can cause bleeding. |
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Term
| when is a c-section indicated in a pregnant pt from a cardiology perspective? |
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Definition
| aortic dissection, marfan syndrome w/dilated aortic root (no 2nd heart sound) and warfarin w/in 2 weeks of labor (will cause fetal intracranial bleeding). |
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Term
| why is lactation encouraged in terms of the heart postpartum? |
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Definition
| good built-in diuretic: get rid of salts and fluid. |
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