heart and blood vessel disorders
Cardiac Arrest and CPR
Standard CPR
Standard CPR combines rescue breathing (mouth-to-mouth resuscitation to supply oxygen to the lungs) with chest compressions that force oxygen-containing blood out of the heart to the brain and other vital organs. The sequence of CPR begins with 30 chest compressions, followed by 2 rescue breaths, and continues in a ratio of 30:2 until the rescuer is relieved by emergency personnel. Chest compressions can quickly tire a person, resulting in compressions that are too weak to circulate blood effectively. Thus, if two or more rescuers are present, they should switch every 2 minutes, or sooner if the rescuer performing compressions begins to feel tired. To do chest compressions in an adult or child, the rescuer lays the person face up, rolling the head, body, and limbs at the same time. The rescuer extends his or her arms and "locks" them straight at the elbows, leans over the person, and places both hands, one on top of the other, in the center of the chest (between the nipples on the breastbone). The rescuer then compresses the chest to a depth ofat least2 inches (5 centimeters) in adults. In children, the rescuer compresses the chestabout2 inches (5 centimeters), and may need to use only one hand to compress in a smaller child. For an infant (up to 1 year old), the rescuer may use two fingers to compress the infant's breastbone just below the nipples to a depth ofabout1½ inches (about 4 centimeters) or ⅓ the diameter of the chest. Alternatively, trained rescuers may choose to encircle the infant's chest with two hands and do compressions with their thumbs. It is important to allow the chest to fully rise back up to its starting height between each compression. After doing 30 compressions, the rescuer tilts the person's head back slightly and lifts the chin, which moves the tongue away from blocking the airway. The rescuer then pinches the person's nose shut, takes a normal breath, seals the mouth over the person's mouth, and blows into the person's mouth for long enough to make the person's chest just rise (about 1 second). This is repeated a second time, followed immediately by another 30 compressions. To do rescue breaths, the rescuer first looks in the mouth and throat for any visible objects that may be blocking the airway and, if any are present, removes them. The rescuer then opens the airway by tilting the person's head and lifting the chin (see figure). The rescuer's mouth covers the person's mouth and then the rescuer exhales air into the person's lungs (rescue breaths). The person's airway must remain open during artificial respiration. To prevent air from escaping from the person's nose, the person's nose can be pinched shut as the rescuer exhales into the mouth (see photo). Artificial respiration is very similar in children and adults. For artificial respiration on an infant, the rescuer's mouth covers the infant's mouth and nose. To prevent damaging the infant's smaller lungs, the rescuer exhales with less force than with adults. If the chest rises, the rescuer should give two deep, slow breaths. Failure of the chest to rise after properly delivering rescue breaths indicates that the infant's airway is blocked, but CPR should continue. Each time the airway is opened during CPR, the rescuer should look for an object in the infant’s mouth and, if one is found, remove it. Standard CPR can be done by one person (a single person alternately does rescue breaths and chest compressions) or by two people (one to do rescue breaths and one to do chest compressions). In standard CPR, a single rescuer gives 30 compressions and then two breaths. If two rescuers are present, when children or infants need CPR, a ratio of 15:2 is preferred, whereas in newborns, a rate of 3:1 is recommended. Compressions are done at a rate of 100 to 120 times per minute in people of all ages. CPR is continued until medical assistance arrives or the person recovers. 