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The preliminary steps of CPR, as defined by the American Heart Association, are (1) calling for help; (2) establishing unresponsiveness in the victim by tapping or gently shaking and shouting at him or her; (3) positioning the victim in a supine position on a hard surface; (4) giving two breaths; and (5) checking the pulse. These are begun as quickly as possible; prompt action is essential for successful outcome. At the moment breathing and heart action stop, “clinical death” ensues. Within four to six minutes the cells of the brain, which are the most sensitive to lack of oxygen, begin to deteriorate. If breathing and circulation are not restored within this period of time, irreversible brain damage occurs and “biological death” takes place.
Although CPR is strongly recommended as a life-saving measure, it is not without danger; specific risks include rib fracture, damage to the liver or heart, and puncture of lungs or large blood vessels. All health care providers should receive instruction and practice in CPR under the direction of a qualified instructor. The public in general should also be encouraged to learn CPR for use in emergency situations.
Once it has been established that a person is in need of CPR, the rescuer immediately begins the “ABC's” of CPR: Airway, Breathing, and Circulation. Opening the airway and determining by look, sound, and feel is the first step for determining whether the person will be able to resume unassisted breathing. This is accomplished by lifting the chin up and back and bringing the mandible forward. If there is no evidence of spontaneous breathing, the rescuer corrects obstruction of the airway by a foreign body, when this is indicated. This is done by one or more of the following methods: back blows, manual chest thrusts, and finger sweeps. Once the airway is open, rescue breathing is started by means of mouth-to-mouth resuscitation (see artificial respiration).
The third element of CPR is circulation, which begins by establishing the presence or absence of a pulse. If there is no pulse, compression of the chest is begun. This consists of rhythmic applications of pressure on the lower half of the sternum (NOT on the xiphoid process, which may injure the liver). For a normal-sized adult, sufficient force is used to depress the sternum about 4 to 5 cm (1½ to 2 in). This raises intrathoracic pressure and produces the output of blood from the heart. When the pressure is released, blood is allowed to flow into the heart. Compressions should be maintained for one-half second; the same length of time is allowed for the relaxation period.
Chest compression is always accompanied by rescue breathing. The two must be coordinated so that there is regular and uninterrupted circulation of blood and aeration of the lungs.
CPR is a psychomotor skill and all health care providers should keep their certification current in order to be proficient in this procedure in case of emergency. The techniques of CPR provide basic life support (BLS) in all cases of respiratory and cardiac arrest. Standards and guidelines for CPR and emergency cardiac care (ECC), including BCLS and ACLS, have been developed cooperatively by the American Heart Association and the National Academy of Sciences–National Research Council. Reprints of these standards can be obtained from local chapters of the American Heart Association or from the American Heart Association, Distribution Department, 7272 Greenville Ave., Dallas, TX 75231-4596, telephone (800) 553–6321.
car·di·o·pul·mo·nar·y re·sus·ci·ta·tion (CPR),
cardiopulmonary resuscitationEmergency medicine The restoration of cardiopulmonary function after cardiac arrest Components Compression of anterior chest wall to stimulate blood flow through the heart, artificial ventilation–eg, mouth-to-mouth breathing, defibrillation. See ABC method, CAB method.
car·di·o·pul·mo·nar·y re·sus·ci·ta·tion(CPR) (kahrdē-ō-pulmŏ-nar-ē rē-sŭsi-tāshŭn)
cardiopulmonary resuscitationAbbreviation: CPR
In emergency cardiac care, CPR involves either opening the airway, providing artificial breathing, and assisting circulation with chest compressions (until definitive treatments can restore spontaneous cardiac, pulmonary, and cerebral function) or providing chest compressions alone, without rescue breathing. When trained providers are available, CPR includes defibrillation with automated external defibrillators. In the U.S., the American Heart Association (AHA) develops and disseminates standard techniques for emergency cardiac care.
The first step in CPR is to ensure that an unarousable patient needs cardiopulmonary support and is not merely asleep or unconscious. If the patient does not respond to a loud voice or gentle shaking, the best thing a rescuer can do is to call for skilled assistance because successful resuscitation usually depends on the speed with which the patient can be defibrillated.
Before the defibrillator arrives, the rescuer can either position the patient for chest compressions only or begin rescue breathing. The patient should be placed supine on a firm, flat surface, with care taken to protect his cervical spine if traumatic injury is suspected. Kneeling at the level of the patient's shoulder, the rescuer performing rescue breathing may open the patient's airway, either with the jaw-thrust or the head-tilt chin-lift technique. If foreign bodies are present in the airway, they must be removed; dentures must also be removed if they interfere with resuscitation. Next, breathing is assessed by listening for breath sounds at the nose and lips and watching for the rise and fall of the chest. If these signs are not present, the patient is apneic, and rescue breathing can be performed. Survival rates of patients undergoing CPR are roughly equivalent with or without rescue breathing.
Rescue breathing can be performed with mouth-to-mouth technique or through a mask with a one-way valve if one is available. The rescuer gives two deep, slow positive-pressure breaths to the patient, the duration of each breath depending on the patient's age. If the supplied breaths meet obvious resistance, the rescuer should make another attempt to reopen the airway, and, if this is ineffective, to clear the airway with the Heimlich maneuver in children and adults. Infants should receive chest thrusts and blows to the back instead of the Heimlich maneuver.
The AHA formerly suggested checking the victim for a pulse after the first two breaths but eliminated the pulse check in its revised guidelines of 2000. If the patient is not breathing on his own, rescue breathing continues. If there is no pulse, external chest compression is begun and continued, with periodically interposed ventilations, until a defibrillator arrives or the patient revives. The precise number of ventilations and chest compressions per minute depends on the patient's age and the number of rescuers. For a single rescuer caring for an adult patient, two breaths are given for every 15 chest compressions. According to the AHA, for resuscitation purposes, infants are those who are up to a year old, children are from 1 to 8 years old, and adults are over the age of 8.
Compressions are given to adults (the usual victims of cardiac arrest) at the center of the sternum between the nipples, with the heel of one hand below the other hand; the fingers of the two hands are interlaced for support and to minimize the possibility of fracturing the ribs. The rescuer's elbows should be locked and straight, and the direction of compression should be exactly perpendicular to the patient's chest.
The chest is depressed 1.5 to 2.0 in for a normal-sized adult. For a child, the chest is depressed 1.0 to 1.5 in; for an infant, 0.5 to 1.0 in. The chest should return to its normally inflated position after each compression.
When professional rescuers arrive, the patient should be defibrillated immediately. If a defibrillator is not available, two-person CPR continues; the two rescuers alternate in giving rescue breaths and chest compressions to minimize fatigue. Ventilation and chest compressions are held for 5 sec at the end of the first minute and every few minutes after to determine whether the patient has responded. illustration; advanced cardiac life support; defibrillation; emergency cardiac care;