abnormal blood flow mechanisms
valves do not close properly, backward blood flow, volume overload occurs
decreased cardiac output and ventricular filling
loss of atrial kick
causes of hypovolemia
hemorrhage, dehydration, burns, GI losses, excessive diuresis
classical symptoms
chest pain/pressure, SOB, nausea/vomiting, radiates to jaw, left arm, back
Degree of stretch of ventricular muscle at end of diastole
valves do not open fully, forward blood flow obstructed, increases pressure in the chamber behind the valve
stenosis
tachycardia = reduced filling time
rapid ventricular response
clinical manifestations of hypovolemia
tachycardia, hypotension, weak thready pulse, cool skin, delayed cap refill, confusion, orthostatic hypotension
atypical symptoms
fatigue, indigestion, dizziness, syncope, mild dyspnea, epigastric pain
Resistance the ventricles must overcome to eject blood
afterload
congenital defects, can cause mixing of oxygenated/ deoxygenated blood
shunts
blood pooling in atria=high risk for stroke, anticoagulation needed
thrombus formation
lab findings of hypovolemia
increased HCT, increased serum sodium, increased BUN/ creatinine ration, and urine specific gravity increases
ECG changes you may see
ST elevation, ST depression or T wave inversion
preload is increased by
hypervolemia, heart failure and regurgitation
decreased ability to eject blood
hypotension, syncope, hf exacerbation
potential progression
findings related to heart failure
fatigue, weight gain, tachycardia, cool extremities, hypoxia
proteins that are released into the bloodstream when heart muscle is damaged, making them key indicators for diagnosing a heart attack
troponin I and troponin T
afterload is increased by
hypertension, vasoconstriction, aortic stenosis
increased BNP=
too much BNP is heart failure
12-24 hours
higher preload = ?
higher afterload = ?
increased workload on heart
decreased stroke volume, increased cardiac workload