cardiopulmonary resuscitation

cardiopulmonary resuscitation (CPR), emergency procedure used to treat victims of cardiac and respiratory arrest. CPR can be done in a hospital with drugs and special equipment or as a first-aid technique. In either case it is done with great urgency to avoid the brain damage or death that result from four to six minutes without oxygen.

The first-aid procedure uses external heart massage (to keep the blood flowing through the body), which may be combined with artificial respiration (to keep air flowing in and out of the lungs). The victim is placed face up and if artificial respiration is to be used, prepared for that. The person administering CPR places his or her hands (one on top of the other, with fingers interlocked) heel down on the victim's breastbone, leans forward, and makes 30 quick, rhythmical compressions (at a rate of about two per second) of about 2 in. (5 cm). This is followed by two breaths, administered using the mouth-to-mouth method of artificial respiration. CPR for infants and children differs in the ratio of compressions to breaths, and the compression of the chest is only 1 to 1.5 in. (2.5 to 3.8 cm). Ideally the procedure is done by two people, one to give mouth-to-mouth artificial respiration and one to apply external heart massage, and special training is recommended.

External heart massage alone may be given if a person is unwilling or unable to provide artificial respiration; studies have shown that heart massage alone can be as effective as both techniques combined. External heart massage only, also known as hands-only CPR, at the rate of 100 compressions per minute, is now considered as acceptable as standard CPR for teenagers and adults who have not collapsed due to breathing problems or drug abuse or who are not drowning victims.

It is recommended that CPR be continued for at least 45 minutes, but if there is no pulse after 20 minutes, experts now recommend considering other prodecures such as extracorporeal membrance oxygenation, in which the blood is circulated through an external filter that oxygenates it. Cardiopulmonary resuscitation in the hospital is an aggressive technique employing drugs and defibrillation equipment, which administers an electrical shock to the heart in an attempt to restore the heartbeat. There is some controversy surrounding its use in patients whose prognosis is poor.

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