cardiac output Flashcards
(18 cards)
CO = ?
SV x HR
normal CO?
5 L/min in resting adult
can vary based on metabolism, age, body size
what is a better way to measure volume of blood ejected from heart?
cardiac index
cardiac index =?
volume of blood ejected from heart per unit time per unit of body surface area
normal cardiac index?
3 L/min/sq of S.A
what is the SV?
volume of blood ejected by ventricle during each contraction
determinants of SV
- end-diastolic volume/ preload
- ventricular contractility
- afterload
tension exerted on cardiac ventricular muscle when it begins to contract
preload
the pressure that the ventricle has to win to produce a SV?
after load
what determines after load?
- ventricular outflow tract
- aortic valve fxn
- peripheral arterial resistance/ bp
intra-ventricular volumer at the end of systole; indicator of systolic fxn
end-systolic volume
what determines ESV?
- preload
- ventricular contractility
- after load
what is a length dependent activation of the heart (when the force of ventricular contraction is a fxn of the ventricular end diastolic length of the cardiac muscle_
frank starling law of the heart
if keep preload & contractility constant, and increase afterload, what happens to SV?
SV decreases
what is the ANREP effect?
when the aortic perssure is elevated abruptly, a positive inotropic effects follows within 1-2 min
when you incr the hr (the rate of stimulation), it incr contraction - what is this phenomenon called?
bowditch staircase phenomenon
effect of HR on CO is ________
rate-dependent
what is the most commonly used method for measuring CO?
pulmonary artery catheterization (PAC) thermodilution w/ blous injxn of cold fluid
