You're absolutely correct,
Charterhouse. You and I both know about that because we've discussed it. I've read also that in some circumstances where the jugular is blocked, cranial swelling can eventually cause restricted airflow. Since the jugular vein (blood going out) is easier to compress than the carotid artery (blood going in), enough blood accumulates in the head and neck to compress the airway, leading to eventually to asphyxial suffocation. While I understand the reasoning behind this, I find it hard to really see it as being very common.
Also, once the brain is deprived of oxygen, brain cells begin dying off. Brain damage is common in people who have been revived from near-death.
Here is a good explanation of how the Carotid reflex works:
Your blood carries oxygen and nutrients to your brain. Enough pressure on the airway (trachea/windpipe) compresses it and prevents oxygen from reaching the lungs. Your body has built-in reflexes to keep this from happening; pressure against your trachea causes quick pain, and you have an irresistible urge to relieve the pressure and cough; one reflex (pain) gets your attention and tries to get you away from the stimulus – say, someone’s thumbs – and the other reflex (cough) attempts to clear the airway. If these attempts are unsuccessful, blood will continue to be pumped to the brain (and elsewhere) by your heart, but it won’t carry enough oxygen and you will lose consciousness in a couple of minutes.
Carotid reflexes. Curiously, you don’t have the same protective reflexes along the carotid artery, so that pressure sufficient to block the artery doesn’t elicit much in the way of defensive reaction. In fact, one of the reflexes that is present may be counterproductive: near where the carotids divide are some nerve cells, the “carotid sinus.” These nerve cells have the normally-useful function of maintaining blood pressure at a steady level. They respond to a decrease in blood pressure (e.g. when you stand up) by constricting arteries and telling the heart to beat harder. Without this, you might pass out every time you stood up suddenly, because not enough blood was reaching your brain. (The dizziness many people feel when they stand up suddenly is another way of appreciating how quickly and exquisitely sensitive your brain is to absence of enough blood). Similarly, the carotid sinus responds to an increase in blood pressure by relaxing the arteries and inhibiting the heart.
So far, so good. The problem arises because these pressure-receptor nerves aren’t smart enough to tell the difference between blood pressure and externally-applied pressure -- for example a forearm or billy-club across the right-front side of the neck.
“Sleeper” hold. Those of you who are wrestling (t.v. variety) fans are probably familiar with the sleeper hold; it is nothing more than a forearm pushed against the right carotid artery, compressing it, and cutting off blood flow to the brain. This causes unconsciousness in about eightto fifteen seconds.
However the sleeper hold is forbidden in tournament wrestling and is faked in the t.v. stuff. The reason is that the amount of pressure needed to compress the artery is enough to cause the carotid sinus to kick into overdrive and send the heart a priority message to SLOW DOWN, which is sometimes enough to stop the heart altogether. Despite being quite aware of this, some police departments continue to use this hold to restrain people they arrest, with the altogether predictable result of infrequent, but entirely unnecessary, deaths.
Another hazard with the sleeper hold is that, during a struggle, the constricting forearm can shift from the side to the front of the neck, compressing the airway and becoming a “choke hold”. This requires greater pressure than the sleeper hold, with a corresponding increase in injuries to neck structures, e.g., fracture of the thyroid cartilage. More dangerously, the lack of oxygen to the heart muscle can trigger fatal cardiac arrest.