Cardiac Hemodynamic Parameters Flashcards
Cardiac Index (CI)
The amount of blood pumped by the heart, per minute, per meter square of body surface area
Afterload
Afterload describes the resistance that the heart has to overcome, during every beat, to send blood into the aorta. These resistive forces include vasoactivity and blood viscosity
Cardiac Output (CO)
The volume of blood pumped by the heart in one minute
Increased CO may indicate high circulating volume
Decreased CO indicates a decrease in circulating volume or a decrease in the strength of ventricular contraction
CVP
CVP readings are used to approximate the RVEDP. The RVEDP assesses right ventricular function and general fluid status.
Low CVP values typically reflect hypovolemia or decreased venous return
High CVP values reflect overhydration, increased venous return or right sided cardiac failure
MAP
Reflects changes in the relationship between CO and SVR and reflects the arterial pressure in the vessels perfuming the organs
A low MAP indicates decreased blood flow through the organs
A high MAP indicates an increased cardiac workload
Preload
Preload occurs during diastole. It is the combination of pulmonary blood filling the atria and the stretching of myocardial fibers. Preload is regulated by the variability in intra vascular volume.
Volume reduction decreases preload
Volume increase will increase preload, MAP, and SI
PAP
Blood pressure in the pulmonary artery.
Increased PAP may indicate: a left-to-right cardiac shunt, pulmonary artery hypertension, COPD or emphysema, pulmonary embolus, pulmonary edema, left ventricular failure
PCWP/PAWP
PCWP pressures are used to approximate LVEDP
High PCWP may indicate left ventricle failure, mitral valve pathology, cardiac insufficiency, cardiac compression post hemorrhage
PVR
The measurement of resistance or the impediment of the pulmonary vascular bed to blood flow
An increased PVR or “pulmonary hypertension” is caused by pulmonary vascular disease, pulmonary embolism, or pulmonary vasculitis, or hypoxia
A decreased PVR is caused by medications such as calcium channel blockers, aminophylline, or isoproterenol or by the delivery of O2
RV Pressure
A direct measurement that indicates right ventricular function and general fluid status
High RV pressure may indicate: pulmonary hypertension, right ventricle failure, congestive heart failure
SI or SVI
The amount of blood ejected from the heart in one cardiac cycle, relative to BSA. It is measured in (ml) per meter square per beat.
An increased SVI may be indicative of early septic shock, hyperthermia, hypervolemia or be caused by medications such as dopamine, dobutamine, or digitalis.
A decreased SVI maybe caused by CHF, late septic shock, beta blockers, or an MI
SV
The amount of blood pumped by the heart per cardiac cycle. It is measured in ml/beat.
A decreased SV may indicate impaired cardiac contractility or valve dysfunction and may result in heart failure.
An increased SV may be caused by an increase in circulating volume or an increase in inotropy
S
SVR
The measurement of resistance or impediment of the systemic vascular bed to blood flow
An increased SVR can be caused by vasoconstrictors, hypovolemia, or late septic shock.
A decreased SVR can be caused by early septic shock, vasodilators, morphine, nitrates, or hypercarbia.
