Cardiopulmonary resuscitation

CPR redirects here. For other meanings of CPR see CPR (disambiguation)

Cardiopulmonary resuscitation (CPR) is an emergency first aid procedure for a victim of cardiac arrest. It is part of the chain of survival, which includes early access (to emergency medical services), early CPR, early defibrillation, and early advanced care. Some first aid organisations also advocate the performance of CPR as part of the choking protocol, if all else has failed.

It can be performed by trained laypersons or by health care or emergency response professionals. It is normally begun on an unconscious patient who is not breathing normally, and continued until the underlying cause can be identified and a pulse is restored (called Return Of Spontaneous Circulation or ROSC). The majority of CPR protocols consist of chest compressions and rescue breaths (i.e. artificial blood circulation and lung ventilation), whereas some protocols now call for performance of the chest compression element only. The intention in both cases is the maintainance a flow of oxygenated blood to the brain and the heart, thereby extending the brief window of opportunity for a successful resuscitation without permanent brain damage.

In 2005, new CPR guidelines were published by the International Resuscitation Councils, agreed at the 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science. The primary goal of these changes was to simplify CPR for lay rescuers and healthcare providers alike, to maximise the potential for early resuscitation. The important changes for 2005 were:

• A universal compression-ventilation ratio (30:2) recommended for all single rescuers of infant (less than one year old), child (1 year old to puberty), and adult (puberty and above) victims (excluding newborns). The primary difference between the age groups is that with adults the rescuer uses two hands for the chest compressions, while with children it is only one, and with infants only two fingers (pointer and middle fingers). Whilst this simplification has been introduced, it has not been universally accepted, and especially amongst healthcare professionals, protocols may still vary.
• The removal of the emphasis on lay rescuers assessing for pulse or signs of circulation for an unresponsive adult victim, instead taking the absence of normal breathing as the key indicator for commencing CPR.
• The removal of the protocol in which lay rescuers provide rescue breathing without chest compressions for an adult victim, with all cases such as these being subject to CPR.

Research has shown that lay personnel cannot accurately detect a pulse in about 40% of cases and cannot accurately discern the absence of pulse in about 10%, the pulse check step has been removed from the CPR procedure completely for lay persons and de-emphasized for healthcare professionals.

The American Heart Association (AHA)/ International Liason Committee on Resuscitation (ILCOR) approach described above has been challenged in recent years by advocates for Cardiocerebral Resuscitation (CCR). CCR is simply chest compressions without mouth-to-mouth (MTM) ventilations. The MTM ventilation component of CPR has been a topic of major controversy over the past decade. In March 2007, a Japanese study in the medical journal The Lancet presented strong evidence that compressing the chest, not MTM ventilation, is the key to helping someone recover from cardiac arrest. This controversy may be coming to a head: an editorial by Gordon Ewy MD (a proponent of CCR) in the same issue of The Lancet calls for an interim revision of the AHA/ILCOR Guidelines based on the results of the Japanese study, but the next scheduled revision of the Guidelines is not until 2010. The initial response of the AHA was that no interim change is necessary.

Cardiac arrest and the place of CPR

The medical term for the condition in which a person's heart has stopped is cardiac arrest (also referred to as cardiorespiratory arrest). CPR is appropriate for cardiac arrest. If the patient still has a pulse, but is not breathing, this is called respiratory arrest and rescue breathing is more appropriate. However, since people often can't tell the difference (can't accurately feel a pulse to determine whether the heart is still beating), CPR is often recommended for both......

The most common cause of cardiac arrest outside of a hospital is ventricular fibrillation (VF), a potentially fatal arrhythmia that is usually (but not always) caused by a heart attack. Other causes of cardiac arrest include drowning, drug overdose, poisoning, electrocution.

Sudden cardiac arrest is a leading cause of death, approximately 250,000 per annum outside a hospital setting in the USA. CPR can double or triple the victim's chances of survival when commenced immediately. According to American Heart Association, only two thirds of victims of a witnessed cardiac arrest are administered CPR. Rapid access to defibrillation is also vital.

Blood circulation and oxygenation are absolute requirements in transporting oxygen to the tissues. The brain may sustain damage after four minutes and irreversible damage after about seven minutes. The heart also rapidly loses the ability to maintain a normal rhythm. Low body temperatures as seen in 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.

CPR is taught to the general public because they are the only ones present in the crucial few minutes before emergency personnel are available. Simple training is the goal of the 2005 guidelines to maximise the prospect that CPR will be performed successfully.

Effectiveness

CPR is almost never effective if started more than 15 minutes after collapse because permanent brain damage has probably already occurred, especially if the person has stopped breathing, since the brain can only survive for 4-6 minutes without oxygen. A notable exception is cardiac arrest occurring in conjunction with exposure to very cold temperatures. Hypothermia seems to protect the victim by slowing down metabolic and physiologic processes, greatly decreasing the tissues' need for oxygen. There are cases where CPR, defibrillation, and advanced warming techniques have revived victims after substantial periods of hypothermia.

Used alone, CPR will result in few complete recoveries, and those that 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 that is not breathing. A pulse check is not required in basic CPR since it is so often missed when present, or even felt when absent, even by health care professionals.

Studies have shown the importance of immediate CPR followed by defibrillation within 3–5 minutes of sudden VF cardiac arrest improve 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 City, without those advantages, the survival rate is only 1-2 percent.

CPR is often severely misportrayed in movies and television as being highly effective in resuscitating a person who is not breathing and has no circulation. A 1996 study published in the New England Journal of Medicine showed that CPR success rates in television shows was 75%.

It is important to note that CPR techniques portrayed on television and in film are purposely incorrect. Actors performing simulated CPR will keep their elbows bent, to prevent force from reaching the fictional victim's heart. Performing unnecessary CPR will disrupt heart rhythms, and may cause heart stoppage.

It is considered by a number of international bodies that in order for CPR to be effective, the guidelines must be simple and easy to remember.

CPR training

CPR is a practical skill and needs professional instruction followed up by regular practice on a resuscitation mannequin to gain and maintain full competency.

CPR skills are not confined to medical professionals, but can (and many would argue, should) be taught to almost all members of the public. Widespread knowledge of CPR has a widespread community benefit, as to be effective, CPR must be applied almost immediately after a patient's heart has stopped. As shown by the Chain of survival, Early CPR on the scene of an incident is essential to the prevention of brain damage during a cardiac arrest. The CPR maintains the blood flow (and consequently gaseous exchange to all organs (including the brain), buying time until a defibrillator and professional medical help arrives.

As with all skills, it is best to obtain training in CPR before a medical emergency occurs, although most modern Ambulance dispatchers will talk an untrained lay rescuer through the process over the phone, whilst the crew is en-route. For the most effective results, hands-on training should be given by an expert. This will enable the person to perform CPR more safely and more effectively. Most organisations advocate regular retraining, in order to keep practice in the skills, and to ensure that the person is up to date with the latest guidelines, which change periodically based on the outputs from governing bodies.

First aid training, including CPR is often provided by a community organisation or charity, with international providers including the Red Cross and St. John Ambulance, or more local providers such as St. Andrew's Ambulance Association in Scotland or the American Heart Association in the United States. There are also many commercial organisations who will train people for a fee, and they often work for employers who wish, or are required by law, to have trained first aiders on site.

In most CPR Classes a simple shortform is used for people to remember everything they need to do. The most common one used worldwide is DRABCD which stands for Danger, Response, Airway, Breathing, Circulation and Defibrillation.

History

Main article: History of CPR

CPR has been known in theory, if not practice, for many hundreds or even thousands of years; some claim it is described in the Bible, discerning a superficial similarity to CPR in a passage from the Books of Kings (II 4:34), wherein the Hebrew prophet Elisha warms a dead boy's body and "places his mouth over his". In the 19th century, doctor H. R. Silvester described a method (The Silvester Method) of artificial respiration in which the patient is laid on their back, and their arms are raised above their head to aid inhalation and then pressed against their chest to aid exhalation. The procedure is repeated sixteen times per minute. This type of artificial respiration is occasionally seen in movies made in the early part of the 20th century.

A second technique, described in the first edition of the Boy Scout Handbook in the United States in 1911, described a form of artificial respiration where the person was laid on their front, with their head to the side, and a process of lifting their arms and pressing on their back was utilized, essentially the Silvester Method with the patient flipped over. This form is seen well into the 1950s (it is used in an episode of Lassie during the Jeff Miller era), and was often used, sometimes for comedic effect, in theatrical cartoons of the time (see Tom and Jerry's "The Cat and the Mermouse"). This method would continue to be shown, for historical purposes, side-by-side with modern CPR in the Boy Scout Handbook until its ninth edition in 1979.

However it wasn't until the middle of the 20th century that the wider medical community started to recognise and promote it as a key part of resuscitation following cardiac arrest. Peter Safar wrote the book ABC of resuscitation in 1957. In the U.S., it was first promoted as a technique for the public to learn in the 1970s. Early marketing efforts oversold the effectiveness of CPR in rescuing heart attack and other victims, and this misperception continues even today, as the success rate for CPR is only 1/20.

Self-CPR

A form of "self-CPR" termed "Cough CPR" may help a person maintain blood flow to the brain during a heart attack while waiting for medical help to arrive and has been used in a hospital emergency room in cases where "standard CPR" was contraindicated. While this technique is not in widespread use, one researcher has recommended that it be taught broadly to the public. However, the American Heart Association (AHA), does not endorse "Cough CPR", which it terms a misnomer as it is not a form of resuscitation. The AHA does recognize a limited legitimate use of the coughing technique:

This coughing technique to maintain blood flow during brief arrhythmias has been useful in the hospital, particularly during cardiac catheterization. In such cases the patient's ECG is monitored continuously, and a physician is present.

"Cough CPR" was the subject of a hoax chain e-mail entitled "How to Survive a Heart Attack When Alone" which wrongly cited "ViaHealth Rochester General Hospital" as the source of the technique. Rochester General Hospital has denied any connection with the technique.

CPR on animals

It is entirely feasible to perform CPR on animals like cats and dogs. The principles and practices are virtually identical to CPR for humans. One is cautioned to only perform CPR on unconscious animals to avoid the risk of being bitten.

See also

• Basic Life Support (BLS)
• Cardiocerebral Resuscitation (CCR), a similar technique.
• CPR mask
• Face shield

External links

• Overview of CPR 2005 - American Heart Association
• Adult Basic Life Support Guideline
• Pediatric Basic Life Support Guideline
• Adult Basic Life Support - American Heart Association 2005
• Pediatric Basic Life Support - American Heart Association 2005
• Adult Basic Life Support International Consensus Statement 2005
• Pediatric Basic and Advanced Life Support International Consensus Statement 2005
• ERC European Resuscitation Council
• Yahoo's CPR Training Directory
• CPR and First Aid at Curlie
• Learn CPR - University of Washington
• Free Online CPR Video
• Akuttjournalen.com - The Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine
• Sudden Cardiac Arrest resources
• How Stuff Works - CPR