Friday, May 4, 2018

First Aid - Shock

Hour 7

Shock: "a rude unhinging of the mechanism of life"

Shock is to be suspected in all cases of injury, even minor ones, and also frequently with serious illness.
It will kill your patient deader than canned tuna, and exactly like spins in aircraft, it's usually observable, gives you warning beforehand, and can rapidly progress to a terminal condition if not dealt with in time.

It falls into several types :
Cardiogenic: a problem with the pump
Obstructive: a problem with circulation
Hypovolemic: a problem with the fluid
Distributive: a problem everywhere
Psychogenic: psychological problems manifesting physical symptoms

References: Warrior Skills Level 1 , pp. 2-30 through 3-32
First Aid, pp. 2-29 through 2-32

Understanding the anatomy (parts), physiology (function), and the pathophysiology (what's going wrong) will help you recognize or suspect shock, and hopefully address, treat, and prevent or reverse it. 

Cardiogenic shock is when the heart isn't functioning or cannot function properly.What you need to know is that the heart gets its blood flow during the resting phase between beats. Blood is pumped into the cardiac arteries on the downbeat, so to speak.

So someone with a rapid heart rate isn't going to be getting enough blood flow (which brings nutrition and oxygen to all muscles, but the heart, beating 100,000 times a day, is going to be the muscle most sensitive to insufficient blood supply) to enable the heart to function as well as when the rate is normal (60-100 beats/minute).
If a cardiac artery is occluded, it's a heart attack.
But injury that occlude or severs that blood flow will have the same effect.

Obstructive shock is any prevention of the blood flow from the heart, as in a tension pneumothorax, is when one (or both) lungs have collapsed due to air or blood displacing the lungs after the chest wall is no longer intact (rib fracture, penetrating trauma, etc.), causing the collapsing lungs to put pressure on the great vessels, and preventing cardiac output from pumping blood to the body.
Massive pulmonary embolism (blood clot in the lung) can thwart things in a similar fashion

Also, the heart beats inside a sack called the pericardium. It doesn't stretch much. Infection there may cause it to fill with fluid. Or an injury to the chest may cause a leak of blood that fills the sack around the heart. Either condition can cause the heart to be constricted by the surrounding fluid, and unable to expand and fill. Think of your heart being, in effect, smothered with a pillow, or squeezed, and you've got the gist of it.

Hypovolemic shock is a lack of sufficient blood in the body to do the work of the circulatory system. It's generally bleeding out of the body's blood vessels, and into somewhere else, like the chest or abdominal cavities, or onto the carpet.

Distributive shock is impaired circulation and thus impaired cell function.
Essentially, the vessels dilate (get big) which functionally creates hypovolemic shock, while at he same time, the capillaries become more permeable, allowing plasma in the bloodstream to move into surrounding tissues, making the problem even worse (and giving you tell-tale swelling), as in anaphylaxis.
Sepsis (body-wide infection) is the primary manifestation, followed by anaphylaxis (massive allergic reaction), and neurogenic shock, where damage to the high nervous system, (brain, spinal cord in the C-spine [neck], and upper t-spine [chest]) can cause the part of the nervous system that controls vessel tension and heart rate is affected. It's a wiring problem that has short-circuited central control. 

Psychogenic shock manifests as fainting, from mental input or stress causing overstimulation of the vagal nerve, which relaxes the tone of blood vessels, causing momentary hypovolemia, lack of sufficient blood flow to the brain, and you pass out.
Severe physical pain, as well as an emotional stress event, can also cause the same effect.

When you know what's going on inside, you know what to look for outside.

The body will shunt blood flow to the heart, lungs, brain, and kidneys, and shut it down to the extremities and other body parts when it's going into shock, as a survival/self-defense reaction.

General signs of shock:

Cool, pale, sweaty skin. - insufficient circulation available to warm or cool skin, compensated by sweating
Weak, rapid pulse - heart trying to move less fluid faster to compensate by higher rate
Paleness, greyness, or
Blotchy, cyanosis (blue skin) - insufficient circulation
Restlessness/nervousness. - insufficient blood flow to brain
Thirst - insufficient fluid available
Bleeding/blood loss - blood not where it's supposed to be
Confusion - insufficient blood flow to brain
Faster than normal breathing. - insufficient blood to move oxygen to tissue, compensated
Nausea/vomiting. - insufficient blood flow to organs of digestion, causing N/V

If no spinal injury is suspected, and/or immobilization and splinting have occurred, the primary treatment is 

* Lay the patient down on their back (lessens cardiac and respiratory workload, and enables blood to make it to the brain easily).

* Elevate their feet higher than the heart (dumps blood from the lower body back to the upper body).

* Loosen restrictive clothing. (improves circulation)

* Cover the patient or shade them (decreases work of circulation to maintain normal body temperature).

* If necessary/advisable, place patient on barrier item to get them off of cold ground, which saps additional body warmth, and forces the cardio-respiratory system to work harder.

* Calm and reassure the patient, and watch for changes in their condition.

I gave you the medical details, because knowing what's going on makes recognizing the signs/symptoms simple, and you'll know it when you see it.
Dealing with it at the first aid level is simple after that.


T-Rav said...

I've heard shock referred to a lot, but didn't have a really good grasp of what it implied (been a while since my last anatomy class).

Thanks for this; it was a really fascinating read.

Badger said...

You're doing good stuff; thanks for it, at least from this end (sample n-1).
Drive on!

TBoone said...

Thanks for this specific/entire effort. I did a 2 day, wilderness 1st Aid course in March. Very well done & good 'baseline/beginning' point. Walked out humbled by how much I didn't know.

Your examples & specifics are easy to follow & Build upon. Logical. Concise. Helpful.
Obviously you know your stuff. More Importantly you have a gift for explaining it to those who aren't at/near or around your level.

Competence builds/feeds confidence. Your lessons increase understanding and build competence.

Much appreciated!

Anon said...


Been a while since I saw it laid out that well. last time *I* tried to do it I failed spectacularly! I actually needed a text to stay on point.

As an aside, at some point, the Shock Cascade expands to attending bystanders and other involved personnel. The responder needs to be ready to treat the cascade as it starts to spread. Because at the very BEGINNING of the spread it can be stopped, OR you can treat for psychogenic shock, as it sets in for the peripheral personnel.