Cardiopulmonary resuscitation (CPR) is an emergency procedure which is performed in an effort to manually preserve intact brain function until further measures are taken to restore spontaneous blood circulation and breathing in a person in cardiac arrest. It is indicated in those who are unresponsive with no breathing or abnormal breathing, for example agonal respirations. It may be performed both in and outside of a hospital.
CPR involves chest compressions at least 5 cm deep and at a rate of at least 100 per minute in an effort to create artificial circulation by manually pumping blood through the heart. In addition, the rescuer may provide breaths by either exhaling into the subject's mouth or utilizing a device that pushes air into the subject's lungs. This process of externally providing ventilation is termed artificial respiration. Current recommendations place emphasis on high-quality chest compressions over artificial respiration; a simplified CPR method involving chest compressions only is recommended for untrained rescuers.
CPR alone is unlikely to restart the heart; its main purpose is to restore partial flow of oxygenated blood to the brain and heart. The objective is to delay tissue death and to extend the brief window of opportunity for a successful resuscitation without permanent brain damage. Administration of an electric shock to the subject's heart, termed defibrillation, is usually needed in order to restore a viable or "perfusing" heart rhythm. Defibrillation is only effective for certain heart rhythms, namely ventricular fibrillation or pulseless ventricular tachycardia, rather than asystole or pulseless electrical activity. CPR may succeed in inducing a heart rhythm which may be shockable. CPR is generally continued until the subject regains return of spontaneous circulation (ROSC) or is declared dead.
CPR is indicated for any person who is unresponsive with no breathing, or who is only breathing in occasional agonal gasps, as it is most likely that they are in cardiac arrest.S643 If a person still has a pulse, but is not breathing (respiratory arrest), artificial respirations may be more appropriate, but due to the difficulty people have in accurately assessing the presence or absence of a pulse, CPR guidelines recommend that lay persons should not be instructed to check the pulse, while giving health care professionals the option to check a pulse.In those with cardiac arrest due to trauma CPR is considered futile in the pulseless case, but still recommended for correctible causes of arrest.
A universal compression to ventilation ratio of 30:2 is recommended.:8 With children, if at least 2 rescuers are present a ratio of 15:2 is preferred.:8 In newborns a rate of 3:1 is recommended unless a cardiac cause is known in which case a 15:2 ratio is reasonable.If an advanced airway such as an endotracheal tube or laryngeal mask airway is in place delivery of respirations should occur without pauses in compressions at a rate of 8–10 per minute.The recommended order of interventions is chest compressions, airway, breathing or CAB in most situations,with a compression rate of at least 100 per minute in all groups.Recommended compression depth in adults and children is about 5 cm (2 inches) and in infants it is 4 cm (1.5 inches).As of 2010 the Resuscitation Council (UK) still recommends ABC for children.As it can be difficult to determine the presence or absence of a pulse the pulse check has been removed for lay providers and should not be performed for more than 10 seconds by health care providers.In adults rescuers should use two hands for the chest compressions, while in children they should use one, and with infants two fingers (index and middle fingers).
Compression only (hands-only or cardiocerebral resuscitation) CPR is a technique that involves chest compressions without artificial respiration.It is recommended as the method of choice for the untrained rescuer or those who are not proficient as it is easier to perform and instructions are easier to give over the phone.In adults with out-of-hospital cardiac arrest, compression-only CPR by the lay public has a higher success rate than standard CPR.The exceptions are cases of drownings, drug overdose, and arrest in children. Children who receive compression only CPR have the same outcomes as those who received no CPR.The method of delivering chest compressions remains the same, as does the rate (at least 100 per minute). It is hoped that the use of compression only delivery will increase the chances of the lay public delivering CPR.As per the American Heart Association, the beat of the Bee Gees' song Stayin' Alive provides an ideal amount of beats-per-minute to use for hands-only CPR.For those with non cardiac arrest and people less than 20 years of age standard CPR is superior to compression only CPR.
During pregnancy when a woman is lying on her back the uterus may compress the inferior vena cava and thus decrease venous return.It is recommended for this reason that the uterus be pushed to the woman's left and if this is not effective either roll the person 30° or consider emergency cesarean section. Other
Interposed abdominal compressions may be beneficial in the hospital environment. There is however no evidence of benefit pre hospital or in children.Internal cardiac massage is manual squeezing of the heart carried out through a surgical incision into the chest cavity. This may be carried out if the chest is already open for cardiac surgery.
Used alone, CPR will result in few complete recoveries, and those who do survive often develop serious complications. Estimates vary, but many organizations stress that CPR does not "bring anyone back," it simply preserves the body for defibrillation and advanced life support.However, in the case of "non-shockable" rhythms such as Pulseless Electrical Activity (PEA), defibrillation is not indicated, and the importance of CPR rises. On average, only 5–10% of people who receive CPR survive.The purpose of CPR is not to "start" the heart, but rather to circulate oxygenated blood, and keep the brain alive until advanced care (especially defibrillation) can be initiated. As many of these patients may have a pulse that is impalpable by the layperson rescuer, the current consensus is to perform CPR on a patient who is not breathing.
Studies have shown that immediate CPR followed by defibrillation within 3–5 minutes of sudden VF cardiac arrest improves survival. In cities such as Seattle where CPR training is widespread and defibrillation by EMS personnel follows quickly, the survival rate is about 30 percent. In cities such as New York, without those advantages, the survival rate is only 1–2 percent.
In most cases, there is a higher proportion of patients who achieve a Return of Spontaneous Circulation (ROSC), where their heart starts to beat on its own again, than ultimately survive to be discharged from hospital (see table below). This is due to medical staff either being ultimately unable to address the cause of the arrhythmia or cardiac arrest, or in some instances due to other co-morbidities, due to the patient being gravely ill in more than one way.
Compression-only CPR is less effective in children than in adults, as cardiac arrest in children is more likely to have a non-cardiac cause. In a 2010 prospective study of cardiac arrest in children (age 1–17), for arrests with a non-cardiac cause, provision by bystanders of conventional CPR with rescue breathing yielded a favorable neurological outcome at one month more often than did compression-only CPR (OR 5.54; 95% confidence interval 2.52–16.99). For arrests with a cardiac cause in this cohort, there was no difference between the two techniques (OR 1.20; 95% confidence interval 0.55–2.66).This is consistent with American Heart Association guidelines for parents.