CPR
From Farscape Encyclopedia Project
Cardiopulmonary resuscitation (CPR) is an emergency medical procedure for a victim of cardiac arrest or, in some circumstances, respiratory arrest. CPR is performed in hospitals, or in the community by layman|laypersons or by emergency response professionals.
CPR consists of artificial blood circulation and artificial respiration (i.e. chest compressions and lung ventilation). CPR is generally continued, usually in the presence of advanced life support, until the patient regains a heart beat (called "return of spontaneous circulation" or "ROSC") or is declared death|dead.
CPR is unlikely to restart the heart, but rather its purpose is to maintain a flow of oxygenated blood to the brain and the heart, thereby delaying necrosis|tissue death and extending the brief window of opportunity for a successful resuscitation without permanent brain damage. Defibrillation and advanced life support are usually needed to restart the heart.
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[edit] Use in Cardiac arrest
The medical term for the condition in which a person's heart has stopped is cardiac arrest. CPR is used on patients in cardiac arrest in order to oxygenation|oxygenate the blood and maintain a cardiac output to keep vital organs alive.
Blood circulation and oxygenation are absolute requirements in transporting oxygen to the tissues. The brain may sustain brain damage|damage after blood flow has been stopped for about four minutes and irreversible damage after about seven minutes. If blood flow ceases for 1 or 2 hours, the cells of the body necrosis|die unless they get an adequately gradual blood flow, (provided by cooling and gradual warming, rarely, in nature [such as in a cold stream of water] or by an advanced medical team). Because of that CPR is generally only effective if performed within 7 minutes of the stoppage of blood flow. The heart also rapidly loses the ability to maintain a normal rhythm. Low body temperatures as sometimes seen in drowning 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.
If the patient still has a pulse, but is not breathing, this is called respiratory arrest and artificial respiration is more appropriate. However, since people often have difficulty detecting a pulse, CPR may be used in both cases, especially when taught as first aid (see below).
[edit] First aid
CPR 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 trainers also advocate the performance of CPR as part of the choking protocol, if all else has failed.
Sudden cardiac arrest is a leading cause of death, happening to approximately one in 8000 people per annum outside a hospital setting in the USA. CPR can double or triple the victim's chances of survival when commenced immediately (see 'effectiveness' below). According to United States 'Annals of Emergency Medicine', only 25% of victims of a witnessed cardiac arrest are administered CPR by a bystander, with a further 33% receiving some CPR as a result of dispatcher instructions. This leaves 41% of victims receiving no CPR prior to the arrival of the emergency medical services.
Rapid access to defibrillation is also vital. 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 myocardial infarction|heart attack and is responsive to defibrillation. Other causes of cardiac arrest include drowning, drug overdose, poisoning, electric shock|electrocution.
[edit] First aid training
CPR is taught to the general public in order to increase the chance to CPR being performed in the crucial few minutes before emergency personnel are available. Simple training is the goal of the 2005 guidelines to maximize the prospect that CPR will be performed successfully.
CPR is a practical skill and needs professional instruction followed up by regular practice on a resuscitation mannequin to gain and maintain full competency. In most CPR classes, a simple mnemonic is used to aid memory of the clinical approach to the unconscious patient and CPR. The most common one used worldwide is ABC (medical)|ABC which stands for Airway, Breathing and Circulation. This may be built upon with extra information (and letters) and can reach complicated levels such as AcBCDEEEFG, explained further in the main article ABC (medical).
CPR skills are not confined to medical professionals, but are regularly taught to members of the public. Widespread knowledge of CPR has a community benefit, as CPR must be applied quickly after a patients heart has stopped. Early CPR is essential to the prevention of brain damage during a cardiac arrest and increases the chance of survival. CPR maintains the blood flow and perfusion to the brain, buying time until a defibrillator and advanced life support|professional medical help arrives.
It is considered best to obtain training in CPR before a medical emergency occurs, although some modern ambulance dispatchers will talk an untrained lay rescuer through the process over the phone, while 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 organizations 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 organization or charity (with or without a fee), 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 organizations, who train members of the public or workers, where the course is paid for by employers who wish, or are required by law, to have trained first aiders on site.
