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The cardiac index (CI) is a hemodynamic measure that represents the cardiac output (CO) of an individual divided by their body surface area (BSA), expressed in liters per minute per square meter (L/min/m²). This parameter provides a more accurate assessment of heart function relative to the size of the individual, as opposed to absolute ...
Therefore, using the assumed Fick determination, the approximated cardiac output for an average man (1.9 m3) is: Cardiac Output = (125 mL O 2 /minute × 1.9) / (200 mL O 2 /L − 150 mL O 2 /L) = 4.75 L/min. Cardiac output may also be estimated with the Fick principle using production of carbon dioxide as a marker substance. [3]
Major factors influencing cardiac output – heart rate and stroke volume, both of which are variable. [1]In cardiac physiology, cardiac output (CO), also known as heart output and often denoted by the symbols , ˙, or ˙, [2] is the volumetric flow rate of the heart's pumping output: that is, the volume of blood being pumped by a single ventricle of the heart, per unit time (usually measured ...
Example: An individual undergoes left and right cardiac catheterization for the evaluation of aortic stenosis. Measurements includes an aortic pressure of 120/60, LV pressure of 170/15, cardiac output of 3.5 liters/minute. What is the aortic valve area? Answer: The peak gradient between the LV and aorta is 50 mmHg. This gives
Based on the Bernoulli equation for incompressible fluids, the product of VTI (cm/stroke) and the cross sectional area of any cardiac structure (cm 2) yields a stroke volume (cm 3 /stroke), which can be used to calculate cardiac output. Qp = VTI RVOT × π × (d RVOT / 2)² <=> Qp = VTI RVOT × 0.785 × d RVOT ²
Velocity Time Integral is a clinical Doppler ultrasound measurement of blood flow, equivalent to the area under the velocity time curve. The product of VTI (cm/stroke) and the cross sectional area of a valve (cm2) yields a stroke volume (cm3/stroke), which can be used to calculate cardiac output.
Modalities applied to measurement of ejection fraction is an emerging field of medical mathematics and subsequent computational applications. The first common measurement method is echocardiography, [7] [8] although cardiac magnetic resonance imaging (MRI), [8] [9] cardiac computed tomography, [8] [9] ventriculography and nuclear medicine (gated SPECT and radionuclide angiography) [8] [10 ...
Using manual input of age, weight and height; body surface area (BSA) and body mass index (BMI) estimates are calculated, so that indexed values may be calculated and displayed, such as cardiac output index (CI) and stroke volume index (SVI or SI). Often available is recording of instantaneous values and display of a long-term trend graph.