I would like to better understand the affects on the human body of a loss of consciousness from a lack of blood supply to the brain and the treatment required after. I am mainly looking at the blocking of the carotid arteries as done during a sleeper hold. I have broken this down into the following parts:

• If the blood supply goes back to normal after a loss of consciousness, is consciousness regained automatically or is CPR or other steps needed in addition for consciousness to be regained?
• If the blood supply is restricted even after a loss of consciousness, will this affect how easily consciousness can be regained? Eg. is there risk of a more severe level of unconsciousness such as a coma, can consciousness still be regained automatically be allowing blood supply back to normal at this point or will CPR or other steps always be required? This goes to the point that sleeper holds are generally recommended to be only held for a maximum of 10-15 seconds, I would like to know the possible medical reasons for this and consequences of going beyond this point.
• Once losing consciousness what would generally be the treatment/steps attempted to regain consciousness?
• Once consciousness is regained via the treatment/steps above, would there need to be any follow up treatment and if so how long would the patient generally need to stay at the hospital for such a treatment or would they be discharged once conscious again?

I am working on a fiction piece and would like to better understand the affects on the human body of a loss of consciousness from a lack of blood supply to the brain and the treatment required after. I am mainly looking at the blocking of the carotid arteries as done during a sleeper hold. I have broken this down into the following parts:

1. If the blood supply goes back to normal after a loss of consciousness, is consciousness regained automatically or is CPR or other steps needed in addition for consciousness to be regained?

Research: In this video, the trauma specialist mentions that once pressure is relieved from the carotid arteries that they will open up straight away, but what does this mean for the rest of the body eg. does the person regain consciousness straight away (if so how quickly) or is there more to it?

2. If the blood supply is restricted even after a loss of consciousness, will this affect how easily consciousness can be regained? Eg. is there risk of a more severe level of unconsciousness such as a coma, can consciousness still be regained automatically be allowing blood supply back to normal at this point or will CPR or other steps always be required? This goes to the point that sleeper holds are generally recommended to be only held for a maximum of 10-15 seconds, I would like to know the possible medical reasons for this and consequences of going beyond this point.

Research: In the first answer here (3rd quote down), it is described that after releasing pressure, the unconscious person generally woke back up after 10-12 seconds. I am interested in what factors determine this wake up eg. if the pressure is maintained for 1 minute vs 15 seconds and then the pressure released, will it take longer for the person to wake up or at what point will they not be able to anymore and need help?

3. Once losing consciousness what would generally be the treatment/steps attempted to regain consciousness?

Research: Most articles I have found on unconsciousness treatment, including this one simply suggest administering CPR if the subject isn't breathing, and contacting emergency help. So I am wondering if the subject is still breathing do you not do anything (other than call emergency help) and they should wake up themselves? Secondly in this specific case is it common for the subject to not be breathing? Thirdly once emergency help does arrive what they would do differently/in addition to the CPR to wake the person up?

4. Once consciousness is regained via the treatment/steps above, would there need to be any follow up treatment and if so how long would the patient generally need to stay at the hospital for such a treatment or would they be discharged once conscious again?

Research: I wasn't able to find anything specific on this, since most articles state that the physician will provide a treatment based on the patient's specific circumstances. In this case, the circumstances are: loss of consciousness due to pressure on carotid arteries, regaining of consciousness via CPR (or other method as per answer to pt 3 above).

I hope that provides enough background. Please let me know if more details/research is needed.