Preload
If one end of a muscle fiber is suspended from a rigid strut and a weight is attached to the free end of the muscle, the muscle will be stretched to a new length.
What is this?
Preload
What is Afterload?
Load imposed against a muscle at the onset of contraction
or
the amount of pressure that the heart needs to exert to eject the blood during ventricular contraction
What are the three components of the vascular system?
Heart, blood vessels, and blood.
What is the normal range for CVP?
0-6 mmHg
Normal range for right and left ejection fraction (EF)
Right ≥ 44%
Left ≥ 55%
Overall normal range is ≥50%
Greater the stretch, the greater the contraction
What is this?
Frank-Starling law
What are the four components of Afterload?
EDV (preload)
Pleural pressure
Vascular impedance (SVR)
PVR
What is vasodilation?
The widening or distension of blood vessels, particularly arterioles, usually caused by nerve impulses or certain drugs that relax smooth muscle in the walls of the blood vessels.
What is the equation for CVP?
CVP = RAP = RVEDP
The pressure in svc is equivalent to the RAP. RAP is equivanlent to the RVEDP
RVEDP and LVEDP ranges
RVEDP= 0-5 mmHg
LVEDP= 6-12 mmHg
What are the characteristics of Diastolic heart failure?
High end diastolic pressure, low end diastolic volume, normal ejection fraction.
High EDP/Low EDV/ Normal EF
What is the Marquis de Laplace 1820 equation?
Tension= pressure x radius/2x wall thickness
What is an anatomic shunt?
Whenever venous blood mixes with arterial blood the overall oxygen count decreases.
Monitoring through ____ is appealing because it eliminates the risks associated with cannulation of the subclavian and internal Juglar veins.
PICCs
What is the stroke volume for right and left ventricular performance?
They are both 20-40 mL/m2
When SBP drops by more than 15 mmHg, what is this called?
Pulsus paradoxus
What is Poiseuille law?
The relationship between airway resistance and the diameter of the airway.
This can falsely elevate the cardiac filling pressures at end-expiration because the intrathoracic pressure is higher than atmospheric pressure.
PEEP
In the absence of mitral valve dysfunction, what is left arterial pressure equal too?
the LAP is equivalent to the left ventricular end-diastolic pressure (LVEDP) and pulmonary artery wedge pressure (PAWP)
PAWP = LAP = LVEDP
What does a change in volume/change in pressure do?
Stiffens the heart
This promotes ventricular emptying and PPV can cause an increase in systolic pressure due to an increase in SV?
Positive pleural pressure
Name four things Shear thinning does
Blood flow increases as vessels decrease in size
Plasma goes faster than RBCs
Increase in plasma volume
Decrease in RBC volume
When respiratory variations are evident, the cardiac filling pressure should be measure at the end of expiration, when ____ is normally at atmospheric level.
Intrathoracic pressure
How is compliance determined?
The compliance of the ventricle is determined by the structural properties of the cardiac muscle as well as by the state of ventricular contraction and relaxation.