Hemodynamics (Part 2) Flashcards
What is Hemodynamics?
Used to describe the forces and mechanics of blood flow
Hemodynamic monitoring allows for the measurement and monitoring of the factors that influence circulation
What does Cardiac output?
Volume of blood ejected by the heart over 1 minute
Normal Range: CO 4-8 L/min
Is determined by SV(stroke volume) and HR (heart rate)
What is the Cardiac index?
CO divide by patients BSA
Range: 2.5-4 L/min
What is the stroke volume?
Volume of blood ejected from the ventricle w/ each beat of the heart
What are factors that affect cardiac output?
Preload, afterload, contractility, HR
What is Preload?
What factors increase preload? Decrease?
Volume (inital stretching of cardiac myocytes prior to contraction)
INCREASED (increased blood volume, pregnancy, exercise, HF, valve regurgitation, increased ventricular compliance)
DECREASED (drugs-venous vasodilators, diuretics;; loss of A-V synchrony, increased HR)
What test measures preload?
Central venous pressure (CVP)
What is the Starling’s Law (Frank-Starling Curve)?
The greater the end-diastolic volume (PRELOAD), the greater the stretch of muscle cells, leading to greater stroke volume
What is afterload?
What increases the afterload? Decreases
Resistance (the pressure that must be overcome to push the blood into the aorta)
What the heart must work against!
INCREASED (vasocontriction, aortic/pulmonary valve stenosis, HTN-systemic or pulmonary)
DECREASED (vasodilation)
What factors causes vasoconstriction of Afterload?
(Test Q)
Drugs (pressors)
DECREASED TEMP (HYPOTHERMIA)
SNS activation
What factors causes vasodilation of afterload?
(Test Q)
Drugs (arterial dilators, exercise, inflammation/infection)
INCREASED TEMPERTURE (TEST Q)
Give arterial dilators to DECREASE afterload (TEST Q)
