Preload Flashcards
What are seven factors that determine preload?
Circulating blood volume, Ventricular compliance, Posture (trendelenburg) Intracavity pressures (ABD HTN), Heart, venous capacity, atrial contraction (A Fib)
What are 5 factors that increase preload?
Increased CVP, increased ventricular compliance, increased atrial compliance, reduced heart rate, increased afterload
What are four factors that decrease preload?
Decreased CVP, impaired atrial contraction, increased HR, decreased afterload
What are four static preload indicators for the left side of the heart
Left Ventricular End Diastolic Volume (LVEDV)
Left Ventricular End Diastolic Pressure (LVEDP)
Left Atrial Pressure (LAP)
Pulmonary artery occlusion pressure (PAOP or PAWP)
Four static preload indicators for the right side of the heart
Right ventricular End diastolic pressure (RVEDP)
Right ventricular end diastolic volume (RVEDV)
Right atrial pressure (RAP)
Central venous pressure (CVP)
What is the use of PAWP and what are the drawbacks
Use: Safety limit.
Drawbacks: does not predict preload, underestimates a poorly compliant left ventricle. Overestimates preload in chronic mitral stenosis, PEEP, Left atrial myocardial, and pulmonary htn
What is the normal CVP
8-12 mmhg
What are the uses for CVP and what can produce an elevated or low CVP?
USE: measures right atrial pressure and right ventricular preload. Does not measure left ventricular preload. Can be used to determine RV failure and RV response to pulm htn
low CVP: volume depletion or decreased venous tone
High CVP: contractile dysfunction or fluid resuscitation
What are ways of measuring the volume of preload?
Continuous end diastolic volume index
Global end diastolic volume index
Descending aorta volume
What are two dynamic preload indicators and what are they used for?
Stroke Volume Variation (normal <10-13%)
Pulse pressure variation
Used to determine response to fluid
