Passage: At the onset of clinical death, consciousness is lost within several seconds. Measurable brain activity stops within 20 to 40 seconds. Irregular gasping may occur during this early time period, and is sometimes mistaken by rescuers as a sign that CPR is not necessary.  During clinical death, all tissues and organs in the body steadily accumulate a type of injury called ischemic injury.

Question: How long does it take to lose consciousness at the beginning of clinical death?
several seconds