Death by Compression Of Carotid Artery?

When George Floyd was pinned by the officer with a knee to the neck, the weight on his neck had to be somewhere about 100 lbs (assuming he didn't put his full weight on the neck). I've seen commentary that if he was able to say "I can't breath" then he could breath and therefore he was lying.

In the neck there are two main arteries, Carotid arteries, one on each side that supply blood to the brain:

The carotid arteries are major blood vessels in the neck that supply blood to the brain, neck, and face. There are two carotid arteries, one on the right and one on the left. In the neck, each carotid artery branches into two divisions

Of particular interest here is:

The carotid sinus, or carotid bulb, is a widening of a carotid artery at its main branch point. The carotid sinus contains sensors that help regulate blood pressure. The carotid artery pulse can normally be felt in the neck by pressing the fingertips against the side of the windpipe, or trachea. [my underlines]

And

Carotid hypersensitivity syndrome: In a few people, applying pressure to the carotid sinus can cause fainting from a sudden drop in blood pressure. Symptoms may occur while shaving or wearing a tight shirt collar. [my underlines]

Of course if a tight shirt can cause fainting and a sudden drop in blood pressure, what would a knee on the neck do? I'm not a doctor, but I'd wager that the pressure to the neck, compressed this artery, possibly on both sides, caused Floyd to eventually pass out and then the continued pressure killed him by either cutting off the flow of blood in to the brain (even though that's an internal artery) or by continuing the low blood pressure that caused a shut down of the body's organs. I'm sure the medical examiner will tell at some time in the near future.,

As for legal consequences. I'm going to continue to be the one who says it's going to be hard to get a murder conviction because police are given great leeway when it comes to criminal intent which is required to secure a murder conviction. I hope that that the prosecutor includes manslaughter, negligent homicide or whatever equivalent law applies so that this cop doesn't walk away clear. I also think that this cop (and likely the ones who watched) may be at serious civil risk, particularly in a post Eric Garner America.