| The medical term for the condition in which a person's heart has stopped is cardiac arrest[9] (also referred to as cardiorespiratory arrest). CPR is used on patients in cardiac arrest in order to oxygenate the blood and maintain a cardiac output to keep vital organs alive.
Blood circulation and oxygenation are absolute requirements in transporting oxygen to the tissues. The brain may sustain damage after blood flow has been stopped for about four minutes[10][11][12] and irreversible damage after about seven minutes.[13][14] If blood flow ceases for 1 or 2 hours, the cells of the body die unless they get an adequately gradual bloodflow[citation needed], (provided by cooling and gradual warming, rarely, in nature [such as in a cold stream of water] or by an advanced medical team). Because of that CPR is generally only effective if performed within 7 minutes of the stoppage of blood flow.[15] The heart also rapidly loses the ability to maintain a normal rhythm. Low body temperatures as sometimes seen in near-drownings prolong the time the brain survives. Following cardiac arrest, effective CPR enables enough oxygen to reach the brain to delay brain death, and allows the heart to remain responsive to defibrillation attempts.
If the patient still has a pulse, but is not breathing, this is called respiratory arrest and artificial respiration is more appropriate. However, since people often have difficulty detecting a pulse, CPR may be used in both cases, especially when taught as first aid.
From Wikipedia, the free encyclopedia |
Article Details