Explain how a carotid choke works.

**DCS** · Posted On: 5/11/2011 3:32pm

Originally Posted by Coach Josh

I believe it is a pressure caused by the restriction of blood flow out of the brain not into the brain. Systolic and diastolic pressure are different the heart pumps blood out with more pressure than it sucks it in.

So when you apply the choke the jugular vein is restricted easier than the carotid. The stoppage or slowing of the blood leaving the brain then causes a back up and the pressure from this causes the person to pass out.

And which is the mechanism that detects this excessive pressure in the brain?

**Coach Josh** · Posted On: 5/11/2011 3:33pm

The vagas nerve

**Snake Plissken** · Posted On: 5/11/2011 3:36pm

Originally Posted by Coach Josh

I am after what causes a carotid choke to work. So far I think we are coming to the conclusion that it is not lack of oxygen. Which is something that we have been told forever.

Not sure what you are looking for, however.....

to the extent that it is oxygenated blood, oxygen would be a factor as the Circle of Willis is not being fed oxygenated blood, causing the common signs and symptoms associated with feinting or syncope.

As DCS pointed out, if all factors are the same in the athletes:
both are of the same health and fitness, neither has any congenital physical problems nor any anatomical anomaly... the choke is going to be most effective if applied at a point "below" or "before" the common carotid bifurcation to the descending or internal carotid and the ascending or external carotid.

The other thing to keep in mind is on the left side of the arch of the aorta, the carotid is its own branch however on the right side, it is a trunk or a branch of the subclavian artery.

This might mean that a choke applied to the right side of the neck may be more effective. Dunno, haven't tested this theory.

Bear in mind that a choke is going to have the ancillary effect of likely reducing airflow while increasing the "stress" of the choked, thus ramping up their fight or flight response, raising their heartrate and increasing their breathing and heartrate, thus decreasing the amount of time it will take for the choke to be effective.

**Snake Plissken** · Posted On: 5/11/2011 3:41pm

Originally Posted by Coach Josh

I believe it is a pressure caused by the restriction of blood flow out of the brain not into the brain. Systolic and diastolic pressure are different the heart pumps blood out with more pressure than it sucks it in.

So when you apply the choke the jugular vein is restricted easier than the carotid. The stoppage or slowing of the blood leaving the brain then causes a back up and the pressure from this causes the person to pass out.

The vagas nerve part is intriguing and I am going to go on this line of thought with that. When the vagas nerve experiences a pressure change it will force the heart to lower the pressure to protect the arteries from rupturing from increased pressure. This will in turn help lower the pressure going to the brain to help prevent damage from the increased pressure.

Now if you continue to choke after they pass out is when you start causing damage. At this point the level of O2 going to the brain is low or stopped and we will start to see brain damage and eventually death.

this will certainly have an effect as the general rule is above the waist, veins lie atop arteries and below the waist they lie below.

So you would need to restrict the vein, and the return of deoxygenated blood to the heart, while restricting the oxygenated blood from reaching the heart.

Although I think this would likely raise blood pressure by having the restricted flow, I am not sure what effect this would have on the syncope.

**CoffeeFan** · Posted On: 5/11/2011 4:21pm

hmmm.... anyone want to attach themselves to a continual HR and blood pressure monitor and then get choked out? FOR SCIENCE!

**Coach Josh** · Posted On: 5/12/2011 9:12am

Sure but it will be in a control type setting with NO STRESS so the initial HR and BP may be up from anticipation but not where it should be when you are rolling. I would say if it was done to get the HR up to over 100 BPM and then slap one on and see what happens.

**Snake Plissken** · Posted On: 5/12/2011 10:10am

and I need to correct my above post:

So you would need to restrict the vein, and the return of deoxygenated blood to the heart, while restricting the oxygenated blood from reaching the heart.

to:

So you would need to restrict the vein, and the return of deoxygenated blood to the heart, while restricting the oxygenated blood from reaching the brain.

From a control type setting, I am guessing you would need a series of baseline tests:
beginning with several "at-rest" settings, several "mild/moderate/intense activity" settings, probably some "before/during/after rolling" settings as well as a fairly intensive and complete screening for the essential physical condition of the test subject.

**Coach Josh** · Posted On: 5/12/2011 10:19am

I would like to ask for a poll to be setup on this thread please.

Carotid chokes work because of

A. No blood gets to the brain thereby cutting of oxygen to the brain and causing a KO.
B. The vagas nerve is stimulated, dropping BP and oxygen to the brain, thereby causing a KO
C. The flow of blood out of the brain is restricted causing a pressure difference that causes a KO.

These are simple summaries of 3 theories we have up feel free to add if I missed one.

**Snake Plissken** · Posted On: 5/12/2011 10:51am

I am going to guess if you are going to list absolutes such as "restriction of oxygenation blood flow" and "negative stimulation of the vagus nerve causing a disruption in neural syntax", you should probably have something in the middle which involves both in the form of a "disruption or disturbance with the blood-brain barrier" which would be similar to the effects of a stroke.

**W. Rabbit** · Posted On: 5/12/2011 11:05am

I think it's a combination of B and C. I don't think it is A because NO blood getting to the brain is not the same as the brain getting poorly oxygenated blood...short of severing the artery, SOME blood will still circulate, and that blood will still contain some oxygen, it will just be of low quality.

Why is it low quality? Because strangulation has excited baroreceptors and caused the vagus nerve to tell the heart to pump 30% slower which means blood volume transmission in the body is down 1/3rd.

The end result is an immediate loss of brain oxygen levels, and because of the slower rate and lowered pressure, it will take time to get proper oxygen delivery restored to the brain. There is no corresponding "spike" to blood pressure following syncope, after all, so it might take up to a minute to wake up without salts or something.

In fact it's the vagus nerve again that helps restore the proper volume/flow/oxygenation. Once the pressure is gone the nerve functions normally and it's primary job is to regulate the entire circulatory rhythm.

Originally Posted by Coach Josh

I would like to ask for a poll to be setup on this thread please.

Carotid chokes work because of

A. No blood gets to the brain thereby cutting of oxygen to the brain and causing a KO.
B. The vagas nerve is stimulated, dropping BP and oxygen to the brain, thereby causing a KO
C. The flow of blood out of the brain is restricted causing a pressure difference that causes a KO.

These are simple summaries of 3 theories we have up feel free to add if I missed one.