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Bleeding can be external or internal and can cause weakness, shock, and death. The cardiovascular system delivers oxygen and nutrients to cells and tissues, and consists of a pump, pipes, and fluids. The heart is a two-pump system, with one side pumping blood to the lungs and the other side pumping blood to the body. Arteries carry oxygenated blood away from the heart, while capillaries allow for the exchange of gases. Blood contains red blood cells that carry oxygen and carbon dioxide. White blood cells fight infections, and platelets are responsible for clotting. Blood flow is important for perfusion, which is the circulation of blood to meet the needs of cells and remove waste products. Adequate perfusion is necessary for organs and organ systems to function properly. Hemorrhage can be visible or invisible, and it is important to estimate blood loss accurately. You can top on that stuff. So it's important to be able to recognize bleeding and understand how bleeding affects the body. Bleeding can be external or internal. Bleeding can cause weakness, shock, and even death. The cardiovascular system circulates blood to cells and tissues. It delivers oxygen and nutrients, carries away metabolic waste, and is responsible for supply and maintaining adequate blood flow. The thick principle states, we unload the red blood cells with oxygen, we deliver the red blood cells to the tissues, we offload the oxygen, unload the waste product of carbon dioxide, others for excretion. Pump, pipe, and fluids. Do I need to run through a drop of blood through the heart again? I think I'd beat you to death with that one. But remember, the cardiovascular system consists of a pump, pipe, and fluids. The heart needs a rich, well-distributed blood supply. It is a four-chambered, two-pump system. Two atrius feed the ventricles, two ventricles feed their respective parts of the body. The right side of the heart is the pulmonary circulation. Takes blood from the body, it's deoxygenated, brings it to the lungs. The left side is the systemic circulation. It takes blood from the lungs and pumps it to the body. The blood is stopped from going backwards through the one-way valves. The tympanic, the pulmonic, the mitral, and the aortic valves. Arteries carry blood, oxygen, away from the heart, except for the pulmonary arteries, which carry deoxygenated blood. The arterioles are those small intermediaries that go from the arteries to the capillaries, because your aorta can be as much as an inch thick. Capillaries are microscopic. I can fit a hundred of them side-by-side on the head of a pen. So I can't stick a garden hose in a drinking straw. I gotta get smaller. And that's what the arterioles do. They go smaller, smaller, smaller, just like the bronchioles, until we get down to that capillary size. Capillaries are the Latin for hair-like. You got billions of them in the body, and that's where the exchange of gases happens. Venules are the small intermediaries like arterioles that come from the capillary and go to the main veins that lead to the vena cava that brings blood back to our heart. Oxygen nutrients pass from the capillaries to the cells. Waste product and carbon dioxide diffuse into the capillaries. We've kind of seen that, right? The oxygen and carbon dioxide diffuse. In the tissues, the oxygen and carbon dioxide diffuse through the interstitial fluid. That's that one to one and a half percent of the body's total fluid volume. Whereas in the lungs, it kind of goes directly from the alveoli into the capillary because all your alveoli are surrounded by capillaries. Blood contains red blood cells, erythrocytes, hemoglobin. Hemoglobin stands for hemi or iron, and globin, oxygen-carrying molecules. So you have one hemi or iron molecule and four globin molecules, each can carry one molecule of oxygen. That's where you get the term hemoglobin. That's why you need iron to have red blood cells. If you're anemic, you'll have reduced red blood cells. Responsible for the transportation of oxygen to the cells and carbon dioxide away, 75% of oxygen is carried to the cells in the hemoglobin, red blood cells, and 75% of the carbon dioxide is also carried. The other 25% is carried in the plasma, and that ends up in the interstitial fluid as well. So your white blood cells are involved in infection fighting. They actually eat the detritus and the antigens in a process called phagocytosis. Platelets are responsible for forming clots. What happens is the platelets, so thrombocytes stick together and they start platelet aggregation, catching red blood cells, and then that causes a clotting cascade that causes this liver, a chemical signal called chemosaxis to the liver, and the liver starts releasing clotting factors. One leads to two, two leads to three, until you get to the 13th clotting factor in the fibrin clot. Little more complicated than that, but that's basically how it works. Clot formation depends on blood stasis. If blood flows, it won't clot. It must stop, or at least slow down significantly. Changes in the blood vessel walls. In your body, all of your blood vessels are under tension. All of the tubes of your body are under tension. If I were to come up to her arm and take a steel saw and go zhoop, sorry, Jesus, scared me, and I go zhoop and cut her arm off, all the blood vessels in her arm would constrict and pull in. You would bleed, but the blood would eventually stop. Soldiers have had amputations on the battlefield and survived for 24, 36 hours before somebody got to them, and they lived because the blood vessels constricted and pulled in. By the same token, a bear comes and bites your arm and rips it off. Those blood vessels are all jagged and they're no longer smooth. They won't contract, but you will bleed out. Does that make sense? And your body's ability to clot. That all depends on clotting factors, platelets, and that kind of thing. When tissues are injured, platelets begin to collect at the sites like at a cut. My platelets start catching the edges of the wound, and that causes platelet aggregation, and then they catch red blood cells, and that begins the clotting cascade. Chemical signal called chemostasis goes up to the liver and it starts releasing the clotting factors. That's due to the fact that the blood is exposed to the air and it starts slowing down. It gets kind of stuck in that wound. That's what happens. That's why you develop a clot. If you were anemic, your blood wouldn't clot as well. So the autonomic system monitors blood, the body needs and adjusts blood flow based upon that, and will automatically redirect blood flow from organs that are not needing blood to those that do, like the heart, the brain, the kidneys, the lungs, the liver. So what'll happen is blood will be shunted from my extremities, shunted from my intestines, back to the core. So those blood vessels will be closed off. It's one of the reasons why patients who develop what they call profound or rapid shock develop modeling, M-O-T-T-L-I-N-G modeling. It's like blotches, like purple blotches on your skin. What that is, is that's blood trapped in the capillary beds because the blood vessels, those sphincters, closed off so quickly, all the blood couldn't leave the capillary beds, and you get blotches. Some people, when they get really cold, when it's outside and they get really cold, they get blotching, too, same reason. You can work like that naturally. Blotching? Yeah. Yeah, you get blood, that's blood in the capillary beds, blood trapped in capillary beds. The body adapts to maintain homeostasis and perfusion. We know that perfusion is circulation of the blood and organ tissue in amounts necessary to meet the needs of the cells and remove waste products. I like this slide because it shows that 99% of all cells do not come in contact with the capillary. The exchange has happened in those interstitial fluids. My heart beats, hydrostatic pressure causes the capillary to swell, fluid leaves it with all the nutrients and oxygen, goes into the interstitial fluid. Cells pick it up, cells release their waste product, which comes back into that tissue, comes back into the interstitial fluid, then when the heart is at rest, it sucks that fluid back into the capillary through an oncotic force, and then returns it in that circulation. Most of your cells are perfused in that way. So, speed of blood flow. Blood has to be fast enough to maintain circulation, but slow enough to allow the cells to exchange oxygen and nutrients. That's why tachycardia is bad. The faster your heart beats, the more poor perfusion you have, because your heart can't get oxygenated, it can't release the oxygen if it's moving like that, right? So that's why you need four milliliters of oxygen, four milliliters of blood for every five milliliters of oxygen at a steady pace. Not too fast, not too slow. All organs and organ systems depend on adequate perfusion to function. Some need a constant supply, like the brain, the heart need a constant supply. Shut it off. Actually, the most irritable organ, the most sensitive organ to lack of oxygen, is actually your heart. People say it's your brain, because they see your mental status, but it's actually your heart. Hold your breath and take your pulse. I guarantee within 30 seconds your pulse will change. Very, very sensitive to oxygen needs. Hemorrhage means bleeding. External bleeding is visible hemorrhage. The problem with visible hemorrhage, the good part of visible hemorrhage is I can see it, I can put a gloved hand on it, I can stop it. The problem is invisible bleeding, right? Non-visible hemorrhage. Internal bleeding. I don't see that, and that can be just as severe. So with external bleeding, it may be difficult to tell the amount of blood loss. You need to be able to estimate blood. What I tell people to do is get some containers, graduated containers, 100 milliliters, half a liter, liter, whatever, different ones. Fill it with red Kool-Aid, throw it on the ground. See what it looks like. Because if I take a gallon of whatever, milk, and hold it up, that looks like a lot. If I pour it on a flat ground, it's not gonna look like anything. So different fluids will look different in different things. Like in the winter, in the summertime, she's wearing that white T-shirt. A little bit of blood, I'll be able to see that. But in the wintertime, he's wearing that and a heavy, dark, black jacket. You could lose a liter of blood in that. I wouldn't even notice it until I touch it. Right? Because the body soaks it up. So you have to recognize that. That's why we have to look at what we call occult bleeding, hidden bleeding. Bleeding that we need to account for. And you guys, when you do your PCRs, anybody who does a trauma, and you don't, I'm gonna tell you in your narrative, you need to estimate blood loss. Estimated 20%, you know, estimated half liter or quarter liter. Estimate high. If you think it looks like 100 liters, 100 milliliters, say 200 milliliters, right? Always estimate high. Better to over than under. Body will not tolerate greater than 20% of the body's blood volume. 20% is a liter. Because the average woman has about, the average adult has about six liters of blood in them. So 20% would be a little over a liter. That's a lot of blood. When you give a blood donation, it's a half a liter, 500 milliliters, or a pint of blood. Your body adjusts for that pretty well. But anything more than that, a liter or more, and that's significant. And one time when I was in the Army, gave two blood donations. Because you get eight hours if you gave a blood donation. I got back in line again. I don't know how I got away with it. I thought they were gonna catch me. I gave a second blood donation. I was. How did you feel after that? I was woofy after that one. And I went out that night, one beer, toast. One beer, I was toast. So significant external blood loss. So significant external bleeding. Changes in vital signs may occur with a significant blood loss. Increased heart rate, increased respiratory rate, a decrease in blood pressure. This is a late sign. This is decompensated. I'm also gonna be altered. How well people compensate for blood loss is relative to how rapidly they bleed. So if I go to Red Cross, and I give a donation of a pint of blood, I do it over 20 minutes, and then I kinda get up and kinda relax, and I go to my arms, do some cookie, I get my T-shirt, I'm okay for the most part. But similarly, if I slice my wrist in a glass window, and I lose that same pint of blood in two minutes or three minutes, my body cannot adjust for that, and I end up in shock. So it's not just the volume, but also how rapidly you might lose that blood. You also have to consider age and preexisting health conditions. If a patient has cardiac history, bleeding is gonna be worse. If he has a history of bleeding disorders or anticoagulant use, bleeding is gonna be worse. If he's on beta blockers, because he's got hypertension, bleeding is gonna be worse, because they're not gonna be able to compensate. Serious conditions with bleeding, significant mechanism of injury, right? So you got high multi-system trauma, God bless you. Patient has a poor general impression, but is calm. Somebody who looks sick, showing injury's sick, like bad injury, and they're calm. That's a bad sign. People should be agitated, they should be scared, they should be nervous, they shouldn't be like, yeah, I'll be okay. That makes me nervous. Signs and symptoms of shock, significant blood loss, especially blood loss that's rapid. Rapid blood loss or uncontrolled bleeding. Arterial bleeding. Arterial bleeding's easy, because you see the blood spurting. If you see blood spurting, that's arterial bleeding, get a gloved hand on it right away. The beauty of arterial bleeding is I know the patient has pulse, so if they're unresponsive, I got blood shooting out of a wound, all right, they got a pulse, put a gloved hand on it, stop it right away. If it's on an extremity, put on a tourniquet. Arterial bleed, don't even bother with pressure dressings and everything, just tourniquet it. If you have arterial bleed in a core, then you're gonna stick, you're gonna pack it. You're just gonna shove, and it's gonna hurt if the patient's awake. You're literally gonna shove packing in that wound. I've told patients with arterial bleeding, hey, put your finger right here, hold it here while I get a dressing. They put their finger right there and stop that bleeding. So, maybe I'm dating myself, but when I took first aid a long time ago, they were always very like tourniquet last resort. Yeah, they don't, they don't, it's changed. Now it's not, now it's all tourniquet. And the reason why is because I could put a tourniquet on right now and finish this class, take it off. My arm isn't gonna feel very good, but it's not gonna do any damage, permanent damage. You can put a tourniquet on for an hour, hour and a half, and it doesn't do any damage. For the short amount of time we have patients, put a tourniquet on. We don't even loosen them. We don't even release them. When you put them on, leave them on. So, don't be afraid to put on a tourniquet. Seriously, knock yourself out. You carry two, use them. So, this is a lack of understanding of like the tissue damage and that it could survive it. Yeah, back then they used to think that the tourniquet caused tissue damage and permanent nerve damage. Now they're finding that it doesn't. It doesn't. A properly applied tourniquet will not cause nerve damage and will save a patient's life. And as long as it's refused, you know, within a couple hours, it's gonna be okay. You're never gonna have the patient a couple hours. And like in the battlefield, when we were in the battlefield training, we would release the tourniquet every hour for 15 minutes or 10 minutes. What I like to do is put it, instead of using a tourniquet, if I have an arterial bleed, if I have a bad bleed, I'll put a BP cuff on and pump it up. And I'll pump it just until the bleeding stops. I still have a pulse, but I control the bleeding with a bandage. So that way the patient has some circulation, but I've stopped the bleeding. The only problem with that is you have to make sure you keep checking it because BP cuffs deflate. So I've gotta make sure I maintain that pressure. If I'm gonna lose the pressure, if I can't watch it, then it's a tourniquet. But I like to do that because at least the patient has some circulation. Venous blood is dark red, flows rapidly, depending upon the size of the vein, but it does not spurt. Capillary bleeding. Capillary bleeding could be bright red because it's oxygenated, but it generally isn't life-threatening, like a deep paper cut type of a thing, right? Flows steadily, but it's not life-threatening. If you call me to go to the hospital for A, I'm gonna kick your ass. I'd transport you. Clotting. Bleeding tends to stop rather quickly in about 10 minutes. Arterial bleeding takes about 10 minutes. If you have an arterial bleed, you would hold pressure on that for at least 10 minutes. If they do an ABG, an arterial blood gas, they actually stick a needle in your radial artery, draw out the blood to get your arterial blood gases. They'll put pressure on that for at least 10 minutes. The worst thing you could do to a wound is this. Every time I do that, what am I doing? Holding a marionette. I'm ripping in the clot, leaving it in place. If I have a bandage on and the blood is soaking through, what do I do? A wound. Put another bandage on top of it and put more pressure. Don't remove the old bandage. So when skin is broken, blood flows rapidly, the cut ends of the vessel begin to narrow, reducing that amount of bleeding. They constrict, they pull in because they're under tension. Then a clot forms. Bleeding will not stop if a clot does not form. So if you have some form of clotting disorder, it will not stop. We talked about hemophilia A, hemophilia B. Hemophilia A is factor VIII deficient. Hemophilia B is factor IX deficient. You could have Von Willebrand syndrome. Basically, these patients, they don't clot properly. True hemophiliac can bleed to death from a paper cut. Bleed to death from a bruise. In oral conditions, if a patient tells you they're hemophiliac and they've got an injury, a bruise, internal bleeding, external bleeding, high priority transport to the hospital. They need factor replacement, or at least platelet replacement. Internal bleeding can be very serious because it's not easily detected. It can lead to hypovolemic shock. Especially like a pelvic injury. If I have a pelvic fracture, I've got large blood vessels flowing through my pelvis. My pelvis is also blood producing bones. Fracture of the pelvis can lead to a rupture of those blood vessels and I can lose two liters of blood in my pelvis. I can bleed to death in my pelvis and have it. Internal bleeding, it could be a stomach ulcer that perforates, a perforated stomach ulcer. Lacerated liver, ruptured spleen, or broken bones. In my humerus, I can lose a half a liter of blood in each one of my upper arms. In my femur, I can lose a liter of blood. I can lose two liters of blood in a bilateral femur fracture. That's like a level two to three, a stage two to three hypovolemic shock. That's a really bad one. Lacerated liver, ruptured spleen. Does anybody remember what the telltale sign for that is? Bleeding from the spleen, bleeding from the liver. Where would I see redness or bruising? Peri-umbilical bruising. If you see bruising, redness, inflammation, distension around the umbilicus, that's a sign of liver or splenic bleeding, classic. Mechanism for internal bleeding. High energy mechanism should increase your suspicion for serious unseen bleeding. Consider things like penetrating or blood trauma. I can have penetrating trauma where the ice pick goes in, it's pulled out, I get no bleeding from that pinhole, but the patient is bleeding severely internally because it lacerated an artery. So don't assume because you don't see external bleeding, there's no internal bleeding, it could be severe. Looking for a decaf ETLS, deformities, contusions, abrasions, punctures, perforations, burns, tenderness, lacerations, and swelling. Internal bleeding is not always caused by trauma. You can have bleeding ulcers, bleeding from the colon. It could be diverticulitis, it could be colitis, it could be Crohn's disease, it could be cancer, it could be a bowel obstruction. Ruptured ectopic pregnancy, the number one cause of maternal demise in the first trimester of pregnancy. A woman of childbearing age who has abdominal pain with or without spotting is considered ectopic unless otherwise proven. And aneurysms, you can have thoracic aortic aneurysms, you can have abdominal aortic aneurysms, it's called the AAA, you can have brain aneurysms. Pain is the most common sign or symptom of bleeding. When frank blood hits nerve endings, it causes pain. They get irritated, they're like, I don't like this, and they cause pain. That's like, did you ever get a bruise and somebody pokes it, oh, look at that bruise, ow, that hurts, don't touch that. That's why, because your nerve endings don't like frank blood and they get irritated from that. So pain is a good indicator of bleeding. Swelling in the area, anytime you see any kind of swelling, it doesn't have to be bruised colored, it could be red, right, or inflamed. Dissension, dyspnea, tachycardia, and hypotension. I would be looking at that as decompensated at that point. A hematoma, a hematoma is a collection of blood in a tissue in a cavity. A bruise is capillary bleeding. A hematoma would be like a lump, and that's a larger blood vessel. I don't know if you've ever gotten an IV, but you get that lump from that, that's called a hematoma. You whack your head, you get an ache, that's called a hematoma because a large blood vessel is ruptured and it's bleeding. Bruising is just capillary blood and that's a contusion. Bleeding from any body opening, blood should not be leaving the body. We have a completely enclosed circulatory system. If it's open, you're bleeding, no bueno. Hepatemesis is vomiting blood. Most commonly, it would be dark, coffee-brown looking from bleeding in the GI system. Melanoma, the dark, tarry, foul-smelling stool that is caused by bleeding in the lower GI system. You could get bright red blood in the stool. We call that hematichesia. That could be injuries to the colon. We could get hemoptysis or coughing up blood. Pain, tenderness, bruising, guarding, or swelling. Anywhere in the body, that's a sign of bleeding.