Cardiology-AACN Flashcards
volume of blood ejected by the heart per minute
cardiac output
what is the normal CO
4-8L/min
volume of blood in the ventricle at the end of diastole
stroke volume
Preload or ___ ___ volume
end diastolic
How do you assess preload
RV: CVP/ RA pressure
normal: 2-6mmHg
LV: PAWP/ LA pressure
normal 6-12 mmHG
How to reduce preload
diuretics/ vasodilators
How to increase preload
volume/ vasoconstriction of venous blood and increases return to RIGHT heart
the pressure the ventricle must generate to open the semilunar valve and eject its contents
afterload
Reflects the overall resistance or impedance to systolic ejection into the entire systemic circulation
SVR or LV afterload
the greatest resistance to flow lies in the:
small arteries and arterioles
Formula for SVR
80 x (MAP-RAP)/CO
Reduction of afterload meds
Vasodilators:
Nitro, Nicardapene, Hydralazine, Lordalil, Ca Channel blockers,
sodium nitroprusside, Ace inhibitors
Increase afterload med
Pressors: Epi, Phenylephrine, Levo, Dopamine, Vasopressin
Normal SVR
800-1200 dynes/sec/cm-5
Causes of increased SVR
volume infusions, peripheral vasoconstriction, Low CO states, hypothermia, increased blood viscosity, hypovolemia, vasopressors, LV failure, alpha-adrenergic agents
Causes of decreased SVR
diuretics, peripheral vasodilation, vasodilators, hyperdynamic phase of sepsis
Pulmonare vascular resistance indicative of
RV afterload
resistance or impedance to right ventricular ejection into the pulmonary vasculature
Pulmonary vascular resistance
formular for PVR
80 x (MPAP-PAOP)/ CO
Normal PVR
<250 dynes/se/cm-5
Causes of increased PVR
hypoxia, pulmonary edema, ARDS, pulmonary emboli, congenital heart defect, pulmonary hypertension , sepsis, valvular heart disease
causes of decreased PVR
vasodilator therapy- prostaglandins/ correction of hypoxia
ability of the heart to modulate its contractile performance independant of preload and afterload
contractility
Normal range of pulmonary artery pressure
15-25/0-8 mmHg
Pulmonary artery pressure high readings reasons:
primary pulmonary hypertension, valvular heart disease
pulmonary
Pulmonary artery pressure low readings reasons:
hypovolemia, vasodilator therapy
average pressure in the circuit during systole and diastole
mean arterial pressure
Normal MAP
70-105
average pressure in the pulmonary circuit during systole and diastole
mean pulmonary artery pressure
normal mean pulmonary artery pressure
10-20mmHg
causes of increased MPAP
volume infusion, pulmonary vasoconstriction, decreased LV contractility, hypervolemia, hypoxia, COPD, Pulmonary hypertension
causes of decreased MPAP
diuretics, pulmonary vasodilation, inotropic therapy (milrinone and dobutamine) hypovolemia
beta receptors are what type of medication
inotrope
Beta 1 receptors are found primarily in the
heart
beta 1 receptors produces increased – and –
heart rate and contractility
example of beta 1 receptors
dobutamine
a1 receptors are found primarily in the
lungs, peripheral arterioles
stimulation of a1 produces
constriction of the smooth muscle
alpha 2 receptors are found primarily
in the brain
stimulation of alpha 2 receptors
promote bronchodilation and block vasoconstriction
Dopaminergic receptors are found in
renal, mesenteric, and vascular beds
stimulation of dopaminergic receptors produce
vasodilation
