Blacking out?

Well, this is a job for one of our medical Flutherers, but basically vasovagal syncope or fainting is not serious and passes quickly. It occurs when a sudden stimulus overloads your nervous system causing a drop in blood pressure resulting in too little blood getting to the brain and loss of consciousness.

Shock is the body’s attempt to deal with serious trauma with loss of blood to the body by taking steps to maintain sufficient blood for the vital organs and brain. It is a cascading response that, if not treated, can result in death.

Marina did an excellent job summarizing vasovagal syncope and shock. I would add that shock is very much a survival mechanism, but typically, if one has experienced true “shock” from blood loss or hemodynamic collapse, survival is very much in question. If you lose a lot of blood, the body attempts to counteract the potential loss in blood pressure (and thus perfusion of the brain) by secreting chemicals (adrenaline and noradrenaline) to squeeze the blood vessels tight (to maintain a higher pressure). However, if you lose enough blood, the pressure must fall, and under those circumstances of shock, survival is low unless blood (and/or additional fluids) are rapidly infused into the person.