The principles of basic life support (BLS) were introduced in 1960. Since then, the specific techniques have been reviewed and revised every 5 to 6 years. The updated guidelines are published in peer-reviewed journals: Circulation in the United States and Resuscitation in Europe. The most recent revision occurred as a result of the 2010 Conference on Cardiopulmonary Resuscitation and Emergency Cardiac Care.
Basic Life Support (BLS) in noninvasive (not involving penetration of the body, such as with surgery or a hypodermic needle) emergency lifesaving care that is used to treat medical conditions, including airway obstruction, respiratory arrest, and cardiac arrest. This care focuses on what is often termed the ABCs: airway (obstruction), breathing (respiratory arrest), and circulation (cardiac arrest or severe bleeding), al though the order in which these actions are performed differs for patients in cardiac arrest. BLS follows a specific sequence for adults and for infants and children. Ideally, only seconds should pass between the time a medic recognizes that a patient needs BLS and the start of treatment. A good thing to remember is that brain cells die every second that they are deprived of oxygen. Permanent brain damage may occur if the brain is without oxygen for 4 to 6 minutes. After 6 minutes without oxygen, some brain damage is almost certain.
If a patient is not breathing well or at all, medics may simply open the airway. Very often, this will help that patient to breathe normally again. However, if the patient has no pulse, medics must combine artificial ventilation with artificial circulation, beginning with compressions. If breathing stops before the heart stops, the patient will have enough oxygen in the lungs to stay alive for several minutes. But when cardiac arrest occurs first, the heart and brain stop receiving oxygen immediately.
Cardiopulmonary resuscitation (CPR) is used to establish artificial ventilation and circulation in a patient who is not breathing and has no pulse. The steps of CPR include the following:
1. First, restore circulation by means of chest compressions to circulate blood through the body.
2. After performing 30 high-quality compressions at least 2" deep in an adult and at a rate of at least 100 per minute, open the airway with the jaw-thrust or head tilt-chin
3. Last, restore breathing by means of rescue breathing (mouth-to-mouth ventilation, mouth-to-nose ventilation, or the use of mechanical ventilation devices).
For CPR to be effective, a medic must be able to easily identify a patient who is in respiratory and/or cardiac arrest and begin treatment with BLS measures immediately.
BLS differs from advanced life support (ALS), which is described on our ALS page. When done correctly, BLS can maintain life for a short time until ALS measures can be started. The effectiveness of ALS is dependent on the existence of high-quality BLS that is started promptly. In some cases, such as choking, submersion, or lightning injuries, BLS measures shall be all that is needed to restore a patient's pulse and breathing. Of course, these patients also require transport to the hospital for evaluation.
BLS Resuscitation. (2012). In A. Pollak, MD, FAAOS (Ed.), Advanced emergency care and transportation of the sick and injured (2nd ed.). Sudbury, MA: Jones & Bartlett Learning.