Module 04 M.A.P. Easy as 1, 2, 3
The concept of perfusion is defined as the ability of the body to deliver oxygen and nutrients to the cells via the blood through the arteries and capillaries, and in turn picking up cellular waste and carbon dioxide from the cells via the veins.
What is needed to maintain adequate perfusion? An adequate Cardiac Output (CO)! Cardiac Output (CO) is the amount of blood pumped out of the heart every minute. CO=Heart Rate (HR) X SV (Stroke Volume). Stroke volume in turn depends on three factors: preload, afterload and contractility. As CO decreases there will be a decrease in tissue perfusion. Decrease tissue perfusion will lead to clinical manifestation. These manifestations of decreased CO will be seen in all the systems. Other causes of tissue perfusion can be organ specific. Narrowing or local vessels, blood clots, and even dilation can affect perfusion o the local organs.
Adequate perfusion is needed by all, so everyone has a potential risk for decreased perfusion. Look at the factors that CO depends on (HR, preload, afterload and contractility) can you think of conditions that may affect those?
- 16-year-old male in a traumatic car accident. That blood loss is affecting his preload.
- 70-year-old female with Heart failure, the disease process is affecting contractility.
- 54-year-old male with a massive inferior wall MI that is causing him to have a decreased HR.
- 60-year-old African American with severe Hypertension, affecting his afterload.
- 9-month-old with vomiting and diarrhea will have a decrease in preload.