ABC (medical)

ABC (and extensions of this initialism) is a mnemonic for memorizing essential steps in dealing with an unconscious or unresponsive patient. It stands for Airway, Breathing and Circulation. Some protocols add additional steps, such as an optional "D" step for Disability or Defibrillation. It is a reminder of the priorities for assessment and treatment of many acute medical situations, from first-aid to hospital medical treatment. Airway, breathing and circulation are vital for life, and each is required, in that order, for the next to be effective.

History of the Mnemonic
The 'ABC' method of remembering the correct protocol for CPR is almost as old as the procedure itself, and is an important part of the history of CPR. It was first seen in a 1962 training video called "The Pulse of Life" created by James Jude, Guy Knickerbocker and Peter Safar. Jude and Knickerbocker, along with William Kouwenhouen discovered the method of external chest compressions, whereas Safar worked with James Elam to prove the effectiveness of artificial respiration. Their combined findings were presented at annual Maryland Medical Society meeting on September 16, 1960 in Ocean City, and gained rapid and widespread acceptance over the following decade, helped by the video and speaking tour they undertook.

Parts of the Mnemonic
The key part of the mnemonic is made up of the first three letters of the alphabet — A, B and C. Together they are designed to remind practitioners of the correct procedure (including the order) in which to deal with a non-breathing patient.

A — Airway
If the patient's airway is blocked, oxygen cannot reach the lungs and so cannot be transported round the body in the blood. Ensuring a clear airway is the first step in treating any patient. Common problems with the airway involve blockage by the tongue or vomit.

Initial opening of the airway is often achieved by a "head tilt — chin lift" or jaw thrust technique, although further manoeuvres such as intubation may be necessary. (See Airway)

B — Breathing
The patient is next assessed for breathing. Common findings during an assessment of breathing may include normal breathing, noisy breathing, gasping or coughing. The rescuer proceeds to act on these based on his/her training. Generally at this point it will become clear whether or not the casualty needs supportive care (such as the recovery position) or Rescue Breathing.

C — Circulation
Once oxygen can be delivered to the lungs by a clear airway and efficient breathing, there needs to be a circulation to deliver it to the rest of the body. This can be assessed in a number of ways, including a pulse check, ECG analysis, or Capillary refill time.

Circulation is the original meaning of the 'C' as laid down by Jude, Knickerbocker & Safar, but in some revised modern protocols, this step stands for Cardiopulmonary Resuscitation or more simply, Compressions, which is effectively artificial circulation. In this case, this step should only apply to those patients who are in Cardiogenic or other form of Shock, and therefore not breathing normally and with an unsatisfactory heart rhythm.

Variations
Nearly all first aid organisations use "ABC" in some form, but some incorporate it as part of a larger initialism, meaning it can vary from the simple 'ABCD' (designed for training lay responders in defibrillation) to 'AcBCDEEEFG' (the UK ambulance service version for patient assessment).

DR ABC
One of the most widely used adaptations is the addition of "DR" in front of "ABC", which stands for Danger and Response. This refers to the guiding principle in first aid to protect yourself before attempting to help others, and then ascertaining that the patient is unresponsive before attempting to treat them. As the original initialism was originally devised for in-hospital use, this was not part of the original protocol.

ABCD
There are several protocols taught which add a D to the end of the simpler ABC (or DR ABC). This may stand for different things, depending on what the trainer is trying to teach, and at what level. It can stand for:
 * Defibrillation — The definitive treatment step for cardiac arrest
 * Disability — Disabilities caused by the injury, not pre-existing conditions
 * Deadly Bleeding

ABCDE
Additionally, some protocols call for an 'E' step to patient assessment. At this point, all protocols diverge from looking after basic life support, and are looking for underlying causes. In some protocols, there can be up to 3 E's used. E can stand for:
 * Environment — only after assessing ABCD does the responder deal with environmentally-related symptoms or conditions, such as cold and lightning.
 * Escaping Air — Checking for air escaping, such as through a sucking chest wound, which could lead to a collapsed lung.
 * Expose and Examine — Predominantly for ambulance level practitioners, where it is important to remove clothing and other obstructions in order to assess wounds.

ABCDEF
An 'F' in the protocol can stand for:
 * Fundus — relating to pregnancy, it is a reminder for crews to check if a female is pregnant, and if she is, how far progressed she is (the position of the fundus in relation to the bellybutton gives a ready reckoning guide)
 * Family (in France): it means that the team must also deal with the witnesses and the family: they can give precious information about the accident or the health of the casualty, they can also be a problem for the team.

ABCDEFG
A 'G' in the protocol can stand for
 * Go Quickly! — A reminder to ensure all assessments and on-scene treatments are completed with speed, in order to get the patient to hospital within the Golden Hour

AcBC
Some trainers and protocols use and additional (small) 'c' in between the A and B, and this stands for 'cervical spine' or 'consider C-spine'. This is a reminder to be aware of potential neck injuries to a patient, as opening the airway may cause further damage, unless a special technique is used.