ABC is acronym for Airway, Breathing and Circulation, defines protocol for performing cardiopulmonary resuscitation, in the care of the unconscious or unresponsive patient. ABC medicine is an emergency procedure to manually preserve intact brain function till a medical intervention is provided to the patient for restoring blood circulation and normal breathing This is employed to assess and treat the patients in acute medical and trauma situations, starting with first-aid to hospital medical treatment.
ABC procedure is performed in the sequence --Airway, breathing, and circulation (in a step-by-step manner) for the next step to be effective.
When patient's airway (nose, nasal passage, trachea and lungs) is blocked, proper breathing would not be possible. The oxygen cannot transport to lungs and not is available or scarce in blood stream for transportation around the body. This could lead to hypoxia (lesser/insufficient amount of oxygen in blood) and a potential cardiac arrest.
Step-wise description of ABC (medicine) protocol
1). Ensure that patient airway is clear, and further evaluate that patient’s breathing is regular and unobstructed. Head-lift-Chin lift procedure is used in cardiopulmonary resuscitation to open the patient's airway. Tilt the head back using one hand and place other hand under the chin to lift the mandible and displace the tongue. Observe the patients breathing pattern for normal respiratory efforts.
2). In the unconscious patient or a patient with reduced level of consciousness; the treatment priority is airway management (that is not smooth) with a blockage of the pharynx-- by the tongue, a foreign body, or vomit. A precaution exercised in time prevents cardiac complications in unconscious patient.
3). In the conscious patient, apart from above listed blockages, other signs of airway obstruction may include-- use of accessory muscles in breathing process, noisy air entry or exit, paradoxical chest movements (Flail chest --a condition in which segment of the rib cage breaks under extreme stress and gets detached from the rest of the chest wall), tracheal deviation (windpipe shifts more towards one side, either left or right due to unequal intra-thoracic pressure), and cyanosis (appearance of a blue or purple coloration of the skin or mucous membranes due to the tissues near the skin surface having low oxygen).
4). Check-out for presence of Chest deformity and movement. The chest should rise during inhale and fall equally on both sides during exhale, and should be free of deformity. Doctors observe a working diagnosis from abnormal movement or shape of the chest.
5). In an unconscious patient, the next priority area after airway opening is to assess is the patient's breathing. Check for normal breathing as against agonal breathing (a series of noisy gasps and labored breathing) occurring in cardiac arrest victims.
6). Observe the respiratory rate--depth and rhythm - Normal breathing is between 8 to 16 breaths per minute in an adult at rest, where as for an infant, a normal rate is up to 44 breaths per minute.
7). Look-out for external breath sounds from the patient at short distance, and check for dysfunction such as a rattling noise (indicative of secretions in the airway) or stridor (which indicates airway obstruction).
8). You physician or para-medic may diagnose for general respiratory distress-- use of accessory muscles to breathe, abdominal breathing (breathing that is done by contracting the diaphragm), position of the patient, sweating, or cyanosis (appearance of a blue or purple coloration of the skin or mucous membranes (due to low oxygen supply to the tissues near the skin).
9). In patients, where a pulse and breathing are clearly recorded, you physician may immediately diagnose for life-threatening conditions --asthma, pulmonary oedema (fluid in the lung) or haemothorax (blood accumulates in the pleural cavity of lungs).
10). In normal breathing situations, medical interventions -- the recovery position and summoning an ambulance is done next.
11). If a patient is having irregular breathing i.e. breathing rate below the minimum rate, then as per current international guidelines by International Liaison Committee on Resuscitation (ILCOR), the chest compression should be started. Begin with forceful chest compressions at a rate of 100 per minute. Position the victim back down on the floor. Place the heel of one hand on top of the other and place the heel of the bottom hand on the center of the victim’s chest. Lock your elbows and compress the chest forcefully; make sure you lift up enough to let the chest recoil.
12).Blood and oxygen circulation is ensured by assessing the presence or absence of circulation through a count/measure of carotid pulse (normally 60-80 beats per minute in a resting adult). Place your index and middle fingers on your neck to the side of your windpipe. Further ECG may be recorded in order to assess heart rhythm, underlying heart condition and to omit possibility of cardiac arrest and myocardial infarctions.
13). Observe the colour and temperature of hands & fingers for indication of poor circulation such as -- cold, blue, pink, pale, or mottled extremities are observed.
14). A Capillary refill (assessment of the effective working of the capillaries), can be done by applying cutaneous pressure (application of pressure on cutaneous region of the skin) to an area of skin, counting the time duration lapsed between a forceful ex-flux of blood from the area and the return of blood.
15). Blood pressure measurements using sphygmomanometer or digital thermometer can be recorded to assess for signs of shock.
16). Observe for the secondary signs of circulatory failure and confirm any incidence of circulatory failure by the presence of signs such as--oedema (build-up of excess fluid in the body tissues) or frothing from the mouth (indicative of congestive heart failure).
17). Clinicians may get a working diagnosis and reach to a prognosis from abnormal movement or shape of the chest in cases such as pneumothorax (an abnormal collection of air or gas in the pleural space that separates the lung from the chest) or haemothorax ( A pleural effusion in which blood accumulates in the pleural cavity of lungs).
18). your doctor may perform auscultation (listening to the internal sounds of the body) and percussion (tapping on a surface to determine the underlying structure) in the chest-region by using a stethoscope to listen for normal chest sounds or any abnormalities.