Cardiopulmonary resuscitation

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Cardiopulmonary resuscitation (CPR) is an emergency first aid protocol for a victim of cardiac arrest.It is also performed as part of the choking protocol if all else has failed. It can be performed by trained lay persons or by healthcare or emergency response professionals. It is normally begun on an unbreathing unconscious person and continued until action can be taken to restart the heart or otherwise diagnose the problem. CPR essentially consists of a pattern of chest compressions and rescue breaths (i.e. artificial blood circulation and lung ventilation) and is intended to maintain a trickle of oxygenated blood to the brain and the heart and thereby extend the otherwise brief window of opportunity for successfully restarting the heart without permanent brain damage. CPR itself is not intended to restart the heart but must be performed continuously until medical responders can attempt to restart the heart by other means.

As 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.^[1]

Many countries have official guidelines on how CPR should be provided, and these naturally override the general description of CPR in this article.

In 2005, new CPR guidelines (Adult Basic Life Support, Pediatric Basic Life Support) were published with input from the American Heart Association, the Heart and Stroke Foundation of Canada and European Resuscitation Council, as agreed at the 2005 International Consensus Conference on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science (Adult Basic Life Support International Consensus Statement 2005, Pediatric Basic and Advanced Life Support International Consensus Statement 2005) . The primary goal was to simplify CPR for lay rescuers and healthcare providers alike to maximise the potential for early resuscitation. The important changes for 2005 are (Overview of CPR):

• a universal compression-ventilation ratio (30:2) is recommended for all single rescuers of infant (less than one year old), child (1-8 years old), and adult (over 8 years old) victims (excluding newborns).[1] The only 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).
• lay rescuers do not need to assess for pulse or signs of circulation for an unresponsive victim
• lay rescuers do not need to provide rescue breathing without chest compressions

Cardiac arrest and the place of CPR

The medical term for a patient whose heart has stopped is cardiac arrest (also referred to as cardiorespiratory arrest), in which case CPR is used. If the patient still has a pulse, but is not breathing, this is called respiratory arrest and rescue breathing is used.

The most common treatable cause of cardiac arrest outside of a hospital is a heart attack leading to a heart rhythm disturbance. Cardiac arrest may be caused by a number of events, including drowning, drug overdoses, poisoning, electrocution and many other conditions.

Sudden cardiac arrest is a leading cause of death, approximately 250,000 per annum outside a hospital setting in the USA [2]. 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 lung ventilation 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 hypothermia victims after over 30 minutes or longer. A patient cannot be pronounced dead before he has been brought back to a normal temperature by appropriate means.

Used alone, few patients will make a complete recovery, 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. As a general rule, CPR has a success rate of only 5 to 10 percent.[3] It is important to understand the purpose of CPR. It is not designed to "start" the heart, but rather to circulate oxygenated blood, and primarily to keep the heart in a shockable rhythm longer to allow for the arrival of a defibrillator. Remember that many of these patients may have a pulse that is unpalpable by the layperson rescuer, and therefore all attempts should be made by the rescuer to perform CPR no matter what state the patient is believed to be in. 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.

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, as the biggest barrier to providing CPR is thought to be the confidence of the rescuer.^{[citation needed]}

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. Training is available through many commercial, volunteer and government organizations worldwide.

CPR training is not confined to the medical professionals. To be effective, CPR must be applied almost immediately after a patient's heart has stopped. Early CPR on the scene of an incident is essential to the prevention of brain damage during a cardiac arrest. Blood flow and air supply to the brain and other major organs is maintained until a defibrillator and professional medical help arrives. Almost anyone is able to perform CPR with training, and health organizations advocate the development of CPR skills throughout the general public.

It is best to obtain training in CPR before a medical emergency occurs. One needs hands-on training by experts to perform CPR safely, and guidelines change, so that training should be repeated every one or two years. Training in first aid is often available through community organizations such as the Red Cross and St. John Ambulance. In many countries in the Commonwealth of Nations, St. John Ambulance and the Medic First Aid Organization provide CPR training. In Scotland, St. Andrew's Ambulance Association provides first aid training. In the United States, the American Red Cross, American Heart Association and American CPR Training also offer CPR training. In addition, many employees at public areas or community centres are trained in CPR. Lifeguards are also trained in CPR and other first aid protocols.

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 DRABC which stands for Danger, Response, Airway, Breathing, and Circulation. However this has now been changed in the UK to Compressions, in conjunction with CPR. Sometimes two additional D's follow the mnemonic for people with higher qualifications and access to additional resources: Defibrillation and Drugs, referring to the use of defibrillators and drugs, such as adrenaline respectively.

History

CPR has been known in theory, if not practice, for many hundreds, if not 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 1950's (it's 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.

Myths and popular culture

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% [4]. The real survival rate of an unwitnessed, out-of-hospital sudden cardiac arrest is in a range of 6% to admission and even less to hospital discharge.

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.^[2][3]

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.^[4]

References

1. ^ http://circ.ahajournals.org/cgi/content/full/112/24_suppl/IV-19
2. ^ Rieser M (May-Jun 1992). "The use of cough-CPR in patients with acute myocardial infarction.". J Emerg Med 10 (3): 291-3. PMID 1624741.
3. ^ Associated Press. "Cough may help during heart attack -- Technique may allow patients to stay conscious, study finds", Oct 31, 2003.
4. ^ CPR for Cats & Dogs. University of Washington School of Medicine.

See also

• Basic Life Support (BLS)

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 the Open Directory Project
• Learn CPR - University of Washington
• Free Online CPR Video
• Akuttjournalen.com - The Scandinavian Journal of Trauma, Resuscitation and Emergency Medicine
• Sudden Cardiac Arrest resources