Blood Belongs in the Body. It's Science.

What is ‘shock’? There are several types of shock but the one we will be going over today is hemorrhagic shock. Basically, it is caused by blood being lost too rapidly for the body to "keep up" or compensate for the loss. We'll talk about what we may expect to see, hear or feel or what our victim may feel if we have a come across a case of hemorrhagic shock.

Think of it like this: When we're talking about shock, think of our body as a hydraulic system like we’ve talked about in the past. You've got the pump (Heart), the tubing/hoses (the vessels) and the fluid (blood). If you've got a problem with one of the three, it's not good but if you have a problem with two of them or, in the worst case scenario, all three, then you're done and the machine fails to function.

In this case, the machine is the body. The average size man (I use man here not being sexist but from a research standpoint) has around 5 liters of blood. There are approximately 350ml per unit. An individual can go into shock by losing as little as 1/5th of their circulating volume or even less. Then there are children, who having a much smaller circulating volume, can't afford to lose much at all. Like we’ve said before, blood belongs in the body because it carries oxygen, vital clotting factors and removes waste. The more blood you lose, the less efficient your body is at delivering oxygen, clotting and removing waste.

So, having talked about what hemorrhagic shock is and how much blood we can lose, we'll get into the 'staging' of shock and some of the signs and symptoms. Quick note: a "sign" is objective, meaning it's something that you as the rescuer will see while a "symptom" is subjective, meaning it's what the victim feels. So we're going to cover the staging of shock. Depending on what lessons you cover, there can be three stages, four stages or five stages. We’ll stick with the four stages set forth by Advanced Trauma Life Support.

In Stage I, the body is able to keep up with the blood loss due to the natural defense mechanism of maintaining homeostasis (balance). The body has lost approximately 750ml (1.5 units)—15% or less of blood during this stage and the vital signs are essentially unchanged. This is due to the vasoconstriction (contraction of the blood vessels) in the body to decrease the diameter of the vessel, which decreases the inner lumen (opening) of the vessel which increases the pressure which ensures all tissues are adequately perfused. You may see a slight elevation in heart rate at this point as the “pump” is working with less volume and trying to do the same job as it was before the injury was incurred. To keep things in perspective, if the femoral artery is dissected, it can lose a little over a liter of blood in 60 seconds or less.

When the victim has lost between 750ml-1500ml—15-30%, they’ll be entering into Stage II of shock. The body is no longer able to compensate for the blood loss and the machine is failing. You may see and feel pale, sweaty skin, increased heart rate (over 120 beats per minute), decreased blood pressure (less than 100 systolic –the top number) and decreased capillary refill and increased respiratory rate (which is the way the body is attempting to ‘fix’ itself by blowing off excess waste products. You should be able to feel a pulse at the radial artery on the wrist (which indicates BP > 80 systolic). Let’s talk about cap refill for a second…Capillary refill is a simple yet effective way to check perfusion status of the victim. To check cap refill, ‘blanch’ the victim’s fingernail by pressing it until it turns white, then let go. In a normally perfused person, the nail bed should turn pink in 3 seconds. Anything longer could indicate a perfusion issue, unless it’s a cold environment, which can cause peripheral vasoconstriction and delay cap refill. If that’s the case, other good areas to look for adequate peripheral perfusion are the gums, the lips and the conjunctiva of the eyes (pull the eyelids down and see if they’re pink or white) Pink is good, white is bad as it indicates a shunting of blood to life-preserving organs. In this stage of shock the victim may also be complaining of feeling anxious or nauseated and may vomit. They may also have an altered mental status. Start checking those pupils. A sluggish constriction of the pupil when light is present isn’t good. This is indicative of inadequate perfusion of the brain. The brain is greedy and loves blood, oxygen and glucose and needs good blood pressure to ensure it is perfused appropriately. Also, please ensure airway is secure at all times.

In Stage III, the victim has lost from 1500ml up to 2000ml (that’s1.5- 2 liters!)—30-40% and will be in dire straits unless treated promptly. The BP will be less than 90 systolic, the heart rate will be 120 or greater, the skin will be cool and clammy with decreased cap refill and they may be in and out of consciousness.

Once the blood loss has reached greater than 2000ml ( 40% or greater of the circulating volume) the victim is in Stage IV of shock where death is imminent unless extremely aggressive resuscitation is attempted and even then, the chance of survival is marginal at best. The signs of this stage of shock are heart rate greater than 140 per minute, blood pressure less than 70, which means one could only palpate a pulse at the carotid artery in the neck and there would be absence of cap refill. The skin will be extremely cool to touch and the victim may be unconscious and the respiratory rate would be greater than 40 per minute, shallow and irregular. Shock, if not treated, can lead to a downward spiral. Excessive blood loss leads to coagulopathy (impaired clotting ability due to loss of important clotting factors), acidosis (body becomes acidic due to excess waste by-products as the body’s natural ability to remove them has been damaged through the loss of blood-no oxygen=anaerobic respiration=acid buildup=death) and hypothermia (the body is unable to maintain normal body temperature)—hypothermia can also be sped up through external environmental factors as well and leads to increased coagulopathy, which leads to more acidosis, because they’re bleeding more and have less oxygen, which leads to impaired ability to maintain normal body temp—the downward spiral also called the “Triad of Death”. Now that you hopefully have a good understanding of what hemorrhagic shock is and how to recognize it.

How do we treat it? First , the bleeding MUST be controlled and stopped by the best means necessary. The faster the bleeding is stopped, the less blood they lose. The less blood they lose, the less the chances are of them going into shock, the better their chances of survival. A person who has the bleeding stopped before advancing into Stage II shock has a 90th percentile chance of survival whereas a person who has gone into Stage II or greater has decreased chances in the 14th percentile.

Once the bleeding is stopped, assess the victim and ascertain the MOI (mechanism of injury). This can tell where the injury may be in the body (ie. Liver, spleen, kidneys—which all bleed quite a bit). The preferred crystalloid IV fluid is LR (Lactated Ringers) according to research by Dr. Frank Butler. Volume expanders are good but whole blood is the best as that’s what the body has lost and needs replacing. IV fluids must also be administered judiciously as the over-dilution of the blood can disrupt the clots which have already formed and lead to a fatal, uncontrollable hemorrhage due to the added fluid increasing the blood pressure. A good rule is to administer enough fluids to maintain a palpable radial pulse. That equates to a systolic blood pressure (the top number- the “squeeze” of the heart that perfuses our tissues) of around 80mm Hg (80 mm of mercury). That’s enough pressure to keep the vital organs perfused.
Basic care of the shock patient after hemorrhage control is keeping them warm (remember cover them completely after exposing, assessing and treating) and following the MARCH/AVPU algorithm. Constant monitoring and reassessing the victim at least every 5 minutes until they are evac’d for any changes in mental status or any visible signs of a rebleed is very important. Mental status changes indicate that the brain isn’t getting perfused and getting the blood, sugar and oxygen it loves so much or that a head injury has occurred and if there are no external signs of bleeding then the victim can be bleeding internally. That’s where the symptom assessment and knowledge come into play.

While shock is comprised of many factors, the treatment is relatively simple. Know the signs and symptoms, know how to treat them and know your kit. Knowing the why and how is extremely important and may just be the difference between life and death.

Stop the bleeding, start the breathing and keep them warm.
Get a kit. Get trained. Be prepared. Win.