Hemodynamics Flashcards
Pulmonary Circulation
heart pumps blood to the lungs where it becomes oxygenated and returns back to the heart
Systemic Circulation
heart delivers blood to all other tissues
Stroke Volume
The amount of blood ejected from the heart in one contraction
Preload
Amount of stretch before contraction in left vent of the heart
Afterload
The force or resistance against which the heart pumps. (in the artery)
Starling’s Law
The more the volume, the more it pumps out until you get to a point where it is overstretched. Then the force of contraction no longer increases in proportion to increased ventricular filling. As a result, blood backs up behind the failing ventricle.
Three mechanisms by which blood gets back to the heart?
Negative pressure in the right atrium
Constriction of smooth muscle in the venous walls
Venous valves and skeletal muscle contraction
What is the cardiac output if the heart rate is 70 beats per min and the stroke volume is 70ml? How would you figure this out?
4.9L
CO=HR x SV
How do we tell whether a patient has lung disease or heart failure?
Check Brain Natriuretic Peptide (BNP) levels, normal is less than 100
Why don’t we check Atrial natriuretic peptide? ANP
Atria releases ANP when the atria stretches too much but the body can adjust and STOPS releasing ANP.
What produces BNP?
Myocytes of the ventricles
What comes with left sided heart failure?
shortness of breath, crackles, fluid in lungs
think left, Pulmonary Fibrosis, orthopnea
Pulmonary fibrosis?
lung tissue is scar tissue so they have extra pressure which crackles
How much blood does the heart pump in a min?
5L or All the blood in the body
What comes with Right sided heart failure?
Edema, JVD, Residual volume increased, brawny skin color
