Elevating the feet during CPR?

[Ridryder 911]

Okay.. your thinking.. but remember Frank Starlings Law is : "the fundamental principle of cardiac behaviour which states that the force of contraction of the cardiac muscle is proportional to its initial length. The energy set free at each contraction is a simple function of cardiac filling. When the diastolic filling of the heart is increased or decreased with a given volume, the displacement of the heart increases or decreases with this volume."

Okay.. see something wrong... contraction, chambers filling... In CPR and death.. there is no contraction.. In compressions you are forcing the blood out by squeezing the heart. Let's find out why a poor heart or dead heart has no blood return and arterial tone!..

Okay Boys & Girls: Let's have some fun !!

It's Anatomy & Physiology Time !....

All right we remember the systemic circulation system (arteries, veins, venules, cappillaries... etc..) right. Now, do we remember the 3 muscles found in each wall the artery & veins ? Thats Right, let's say them together ! :

Tunica Adventitia

Outermost layer. Made primarily of loose connective tissue. Anchors the blood vessel to the surrounding tissue.

Tunica Media

Consists primarily of smooth muscle and is responsible for vasoconstriction and vasodilation. Usually the thickest layer in arteries.

Tunica Intima

Endothelium overlying the bare connective tissue. It acts as a selectively permeable barrier to blood solutes (wow!). Secretes vasoconstrictors and vasodilators (later lesson). Provides a smooth surface that repels blood cells and platelets.

*Note that capillaries contain only a tunica intima.

Arteries

Let's begin by discussing arteries. They are constructed to withstand surges of blood pressure associated with ventricular systole. They're more muscular than veins and appear relatively round in tissue sections.

Remember there are 3 basic categories of arteries:

Conducting (or Elastic) Arteries

These are the largest. Examples include the aorta, pulmonary arteries, and the common carotid arteries. Their tunica media contains a great deal of elastic tissue. Now this elastic tissue allows for expansion during ventricular systole (contracition) and recoil during ventricular diastole (resting). This helps create continuous flow from a discontinuous pump.

Th following pics, please look at the elastic tissue within inside the artery wall and how it functions to maintain blood flow.

Distributing (or Muscular) Arteries

Smaller branches that distribute blood to individual organs. They typically have 25-40 layers of smooth muscle cells.

Examples include the brachial, femoral, and splenic arteries (now you know why the spleen is full of blood!) (among many others).

Without tone or nerve reflex you loose the muscle tone.. thus pooling and the only return would be what little circulation from compressions (which is very little)

I can add more if interested... on physiology of why loss of muscle tone of circulatory in shock if there is an interest on another post..

R/R 911..

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[Katiebug]

Wow. Now that was a good answer!