Left to Right Shunts and their Calculation Ghada ... - CardioEgypt.com
Left to Right Shunts and their Calculation Ghada ... - CardioEgypt.com
Left to Right Shunts and their Calculation Ghada ... - CardioEgypt.com
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3/18/2013<br />
Cardiac Output Measurement<br />
Fick Oxygen Method<br />
• Sources of Error<br />
– Spec<strong>to</strong>pho<strong>to</strong>metric determination of blood<br />
oxygen saturation<br />
– Changes in mean pulmonary volume<br />
• Patient may progressively increase or decrease<br />
pulmonary volume during sample collection. If<br />
patient relaxes <strong>and</strong> breathes smaller volumes, CO is<br />
underestimated<br />
– Improper collection of mixed venous blood<br />
sample<br />
• Contamination with PCW blood<br />
• Sampling from more proximal site<br />
Baim DS: Grossman’s Cardiac Catheterization, Angiography, <strong>and</strong> Intervention. 7 th Edition. Lippincot Williams<br />
<strong>and</strong> Wilkins, 2007.<br />
Indica<strong>to</strong>r Dilution Methods<br />
• Requirements<br />
– Bolus of indica<strong>to</strong>r substance which mixes<br />
<strong>com</strong>pletely with blood <strong>and</strong> whose concentration<br />
can be measured<br />
– Indica<strong>to</strong>r must go through a portion of circulation<br />
where all the blood of the body be<strong>com</strong>es mixed<br />
Baim DS: Grossman’s Cardiac Catheterization, Angiography, <strong>and</strong> Intervention. 7 th Edition. Lippincot Williams<br />
<strong>and</strong> Wilkins, 2007.<br />
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