On television and in the movies, people who collapse due to cardiac arrest and receive cardiopulmonary resuscitation (CPR) often awaken during, or after, CPR is done.
In real life, it is much less likely that people will be revived by CPR itself. Instead, CPR is done to circulate oxygen-containing blood from the lungs to the brain and organs until the heart can be restarted with a defibrillator, often with the help of special drugs given by emergency medical services personnel.
Only a small percentage of people who suffer cardiac arrest will survive until they reach a hospital. Even those who reach the hospital alive often die as a result of the underlying heart problem before they can be discharged. Of those people who are able to leave the hospital, many will not regain their normal mental function. The most important factors that influence whether a person will survive cardiac arrest and return to normal life after hospital discharge are early initiation of CPR and early defibrillation.
Usually in television or film, CPR is done on a young, relatively healthy person, sometimes someone who has suffered a serious injury. In reality, most people who need CPR are older adults who often have many serious underlying illnesses. These people are much less likely to have a good outcome after CPR. Also, CPR is rarely effective if the cause of cardiac arrest is a traumatic injury.
In television and film, the person either dies or recovers fully. In reality, many people who survive cardiac arrest have serious disabilities as a result of the lack of blood flow to the brain.