Shock - Why?

[imurphy]

Hey guys.

From reading a couple of threads here, and thinking back on my course, the EMT-B is told a lot of things that can be wrong with patients, but are rarely told why it's happening. I think the Why's are so important but not many people, especially during their course, will look for the why's, just accepting the fact that it happens. With this in mind, here are "The Why's of Shock"

Shock: The Definition
A condition characterized by signs and symptoms indicative of inadequate organ and tissue perfusion

1. Change in the level of consciousness; anxiety, apathy, confusion, disorientation and coma.
Why does this happen?
The brain is the most oxygen dependent organ in the body and would be the first to indicate a hypoxic state

2. Color becomes pale. Ashen or Cyanotic
Why does this happen?
This is due to the peripheral constriction of blood vessels ans shunting of blood to vital organs. Absence of blood to an area is what causes the loss of color.

3. Skin may feel cool to the touch
Why does this happen?
Peripheral vasoconstriction shunts the blood and the warmth to the vital organs leaving the skin cool.

4. Patient may be diaphoeritic (sweaty)
Why does this happen?
Side effect of adrenalin from the "Fight or Flight" response.

5. Pulse is rapid and thready
Why does this happen?
In an effort to compensate for the hypoxic state in the organs, the heart increases its rate to circulate oxygenated blood faster

6. Respirations are rapid and shallow
Why does this happen?
The faster circulating blood must be oxygenated more rapidly

7. Patient may complain of thirst
Why does this happen?
The body compensates for fluid loss by drinking fluid in response to thirst.

8. Patient may complain of nausea and vomiting.
Why does this happen?
Another manner of compensating for the hypoxic state is to shunt blood from the digestive tract to the vital organs

9. Blood Pressure is low and falling.
Why does this happen?
Blood pressure is maintained by a functioning heart, an intact circulatory system and an adequate supply of blood. When any of these are no longer functioning properly, the pressure in the system falls. Initially the system compensates to maintain the BP but this soon fails with subsequent crash of BP

10. Pupils may be dilated
Why does this happen?
This is a response of the brain to a lowered oxygen supply

I hope this answers some of the whys for the newer EMT's!

 

[EMT-P633]

Excellent post!!!

 

[mycrofft]

"Shock" was not always a concept. It became prominent in the '60's.

Recongition of this collection of signs and symptoms associated withn a certain course of disease (syndrome) started in WWII and gained legs during the Korean Conflict. The big feature of shock which they found so enrossing back then was that there appeared to be a "tipping point" beyond which retrieval was impossible. The next paradigm shift after defining the syndrome was to define at what point it started, leading to earlier and relatively milder interventions (e.g., closed chest cardiac massage,or CPR, on the scene versus open chest cardiac massage in the OR). Now we talk about someone "looking shocky" and taking measurs to prevent it occurring rather than virtually waiting for collapse, then snatch and run.

 

[Ridryder911]

Here is the real reason...http://www.doctorhays.com/Physio/lecture14-outputflow1.pdf


Remember, that the capillaries has about seven miles of tubes.. there are precapillary sphincter and post-capillary sphincters that are adjusted to the pressure gradient and amount of aldosterone to secrete ADH to angiotensin I and II.

Remember the body conserves all that blood flow needed (brain, heart, kidney) and reserves fluid .. hence anti diuretic hormone. Hence the sympathetic response of "flight or flight".

* If the body is to "conserve water" why is it some people will pee themselves when scared or in shock?....

 

[mycrofft]

To taste bad?

:blush:..........

 

[Scout]

:blush:..........

Not too far off according to some sources i have read, think of it would you eat something with **** all over it.


murph very good post but why

 

[BruceD]

* If the body is to "conserve water" why is it some people will pee themselves when scared or in shock?....

My guess is the sudden, short duration spike of parasympathetics just as the sympathetic response is ratcheting up in response to the body trying to compensate for shock?

 

[JPINFV]

Or it could be that the urine in the bladder has already been removed from circulation prior to the event taking place.

 

[daedalus]

Or it could be that the urine in the bladder has already been removed from circulation prior to the event taking place.

Spot on.
The kidneys cannot reabsorb fluids already in the bladder. KISS (keep it simple....)

 

[mycrofft]

daedelus, what if it's a really good TV show...

.........

 

[apagea99]

This post is perfect for me right now....we're just getting into the chapter on bleeding and shock . Our book discusses some of the whys, but not all. Thirst, pupil dilation, and cyanosis in the lips and nail beds were mentioned as some "extra" symptoms to look for, but there was no explanation as to why they occurred.

Thanks for adding to the knowledge base!

 

[JPINFV]

Thirst: Your blood is about half water (plasma is ~55%, of which 90% is water). Thirst=drinking=more water

Pupil dilation and peripheral cyanosis: Sympathetic nervous system activation ("fight or flight"). Some actions of sympathetic nervous system is vasoconstriction, increased pulse rate, increase stroke volume, and pupil dilation. Time for some math here.

Cardiac Output (CO)=(heart rate)(stroke volume)
Mean Arterial Pressure (MAP)=((1/3systolic pressure)+(2/3 diastolic pressure))/3 = (CO)(systemic vascular resistance)*

Essentially MAP is your average blood pressure over a cardiac cycle. (contraction/relaxation). To increase your average blood pressure you can either increase your cardiac output by having the heart pump faster and harder or by constricting the peripheral arterioles (or both). A side effect of sympathetic activation is pupil dilation. Similarly, with less blood reaching the peripheral (lips, fingers, toes, etc. Things that can stand to have less blood flow longer than your core organs and things you could live without if need be) will cause it to become cyanotic just as if the patient was hypoxic because those regions are essentially hypoxic for the good of the entire organism.

*I'm leaving off a "+(central venous pressure)" because it isn't large enough to generally be important.

 

[rhan101277]

I don't know if this post has much to do with the OP question but I wanted to put it out there. I used to have panic attacks and now after school, I understand why I was feeling the way I was. My hands, feet, lips were tingled because I was blowing off to much carbon dioxide. Also my pulse rate was extremely high causing my stroke volume to be low. There is a bunch of other stuff going on that I don't understand during these episodes. All I know is that it was very dangerous and I am glad I don't have them anymore. It is amazing how the human body works to try to keep itself alive. I do wonder how come during these episodes of extremely high blood pressure, how come my arteries didn't dialate to lower blood pressure, but maybe my system knew if it did that, since I was actually getting less blood in circulation that it would cause more issues. I am learning a lot in A&P as well.

 

[daedalus]

I don't know if this post has much to do with the OP question but I wanted to put it out there. I used to have panic attacks and now after school, I understand why I was feeling the way I was. My hands, feet, lips were tingled because I was blowing off to much carbon dioxide. Also my pulse rate was extremely high causing my stroke volume to be low. There is a bunch of other stuff going on that I don't understand during these episodes. All I know is that it was very dangerous and I am glad I don't have them anymore. It is amazing how the human body works to try to keep itself alive. I do wonder how come during these episodes of extremely high blood pressure, how come my arteries didn't dialate to lower blood pressure, but maybe my system knew if it did that, since I was actually getting less blood in circulation that it would cause more issues. I am learning a lot in A&P as well.

Rhan, as a "resident expert" in panic attacks, I can tell you they they are not really dangerous to your physical health (they can be incredibly destructive on your social life however). Although many things are going on inside of your body, including the activation of your sympathetic nervous system, you are in no real danger, and even if you were to pass out, your body would "correct itself" and you would be fine.