This document discusses medical emergencies and provides guidance on how to respond. It notes that television portrayals of medical emergencies are not always accurate. The best way to revive someone in cardiac arrest is through cardiopulmonary resuscitation (CPR), which involves chest compressions at 100 per minute and artificial breathing to restart blood flow before brain damage occurs. CPR may be effective for drowning victims only after they have been removed from the water. In some cases, cold water submersion can preserve brain function even after prolonged submersion times.