Bleeding is Bad...mmmkay?

The more we understand the basic functions of our body, the more we’re able to understand and rationalize what needs to be done in an emergent situation. So, let’s take a quick look at how our circulatory system functions and why it’s important to keep blood where it belongs.

There are a lot of misperceptions about venous and arterial bleeding. What is bright red and what is not? What is steady and what pulses? To know how to better take care of a bleed, we need to understand how blood circulation works.

Our body is a hydraulic machine. The heart is the pump, the vessels are the hoses/tubing and the blood is our hydraulic fluid. Pump, Tubing, Fluid. Any interruption of one of these components could make the machine break down if it’s left unchecked. It’s up to us to be the mechanic and fix it.
Basically, as we inhale, we take in oxygen, it’s absorbed at the microscopic capillary level in our lungs and attaches to red blood cells, as we exhale, the waste, carbon dioxide, is expelled from our body. Our body has a very fragile pH system and must remain at 7.35-7.45 to maintain balance. Too much in either direction can have dire consequences.

The Pump. The oxygen binds to a substance in our red blood cells called hemoglobin. This blood is pumped back to the heart by the pulmonary veins (the only veins in the body that pumps oxygenated blood), it goes into the left atrium (top left chamber of the heart) through the mitral valve and squeezed up through the muscular left ventricle (bottom left chamber of the heart) through the aortic valve into the central circulation and out to all of the tissue in the body by way of arteries, arterioles and capillaries perfusing our organs and tissue with life-sustaining oxygen. As this is happening, the unoxygenated blood is traveling up through the venules and veins, by vacuum and a series of valves in the veins to prevent backflow of the blood, into the central circulation to the superior and inferior vena cava and then enters the upper right chamber of the heart (the right atrium). It flows from there through the tricuspid valve into the right ventricle (the lower right chamber) up through the pulmonary valve and through the pulmonary artery (the only artery which carries deoxygenated blood) back into the lungs to exchange waste for oxygen. All of this happens around 80 times per minute for the average person.

The Tubing. Vessels can be broken down into arteries, arterioles, capillaries, venules and veins. Arteries have 3 layers and veins have two. If this complex network of vessels in your body were laid end-to-end they would measure close to 60,000 miles! (and you’d be dead.—Medical Joke) Think of arteries as a high pressure fire hose and veins as a low pressure garden hose without a spray nozzle on the end. Arteries are thick and muscular as they have to support the high pressures of the blood being ejected from the left ventricle into the aorta with great force. Veins typically have a lower pressure as the blood in them than arteries do and have a series of valves which prevents backflow of blood which could cause serious health issues.
These vessels range in size from the size of a small hose to microscopic in nature. If an artery is dissected, the blood will spray from it much like water from the nozzle of a fire hose. It will be bright red due to it’s high oxygen content and will ‘spurt’ in a pulsatile manner due to the contraction of the heart.
If a vein is dissected, blood will flow in steady fashion and be dark red in color, due to the waste products, low oxygen content and low pressure.

Typically, an injury to an artery is more worrisome than a venous injury due to the high pressure and high volume of loss in short period of time. However, dissecting a large vein like the brachial, basilic, femoral or subclavian can have devastating effects as well as they can lose a lot of blood very quickly. So, basically, bleeding is bad. M’kay?
The Fluid. 5 liters of the red stuff is what we the average person contains. The goal is to keep as much of it in the body as possible. Why? Blood has our clotting factors (fibrin, thrombin, platelets) which help stop the bleeding naturally and it has our oxygen-carrying capability (hemoglobin) which helps perfuse all of our organs with oxygen. The more blood you lose, the less you’re able to clot, the more you bleed, the less oxygen you get to all the tissues, the more waste products (acid from excess carbon dioxide and lactic acid) build up, the more likely you are to go into shock, the more your body can’t warm itself, the colder you get, the more it affects clotting, the more you bleed, etc., etc. This vicious cycle is known as the “Triad of Death”. Pretty fascinating stuff. So, the more blood you lose, the higher your chances of dying. Blood belongs in the body. It’s science.

That’s our circulatory system in a nutshell. Our bodies have a wonderful way of attempting to compensate and maintain that fine balance but can only take so much of an insult before decompensation and death occur. It’s up to us to understand not only what to do, but why we’re doing it, the rationale behind it and what to look for. The more we understand how our bodies work, the more effective “mechanic” we can be when we break down or get into a wreck. This is why we recommend getting the training when you get a kit. Just remember, “Stop the Bleeding, Start the Breathing.”, because whether you do anything or not, all bleeding will eventually stop.

Blood Belongs In The Body. It's Science.

-Pocket Doc