The ABCs of nursing assessment (Airway, Breathing, and Circulation) provide a foundational, systematic approach to rapidly evaluating and managing patients in emergency and critical care settings. This acronym establishes a clear hierarchy for prioritizing life-saving interventions. A problem with a higher-priority letter must be addressed and corrected before moving to the next step. This order ensures that the most immediate threats to life are managed first, which is crucial in high-pressure situations. The sequence allows for a focused, time-sensitive assessment concentrating only on the physiological requirements necessary to sustain life.
Prioritizing Airway Clearance
The ‘A’ for Airway is the absolute first step because obstruction prevents oxygen from reaching the lungs, leading to rapid deterioration. Assessment involves looking for foreign objects or listening for abnormal sounds like snoring, gurgling, or stridor. Snoring indicates the tongue may be blocking the pharynx, while gurgling suggests liquid secretions (blood or vomit). Stridor, a high-pitched, harsh sound, signals severe narrowing of the upper airway, often due to swelling.
Initial interventions focus on simple maneuvers to open the passage and ensure patency. For patients without suspected neck injury, the head-tilt/chin-lift technique repositions the head. If a cervical spine injury is a concern, a jaw thrust maneuver is used instead, as it achieves the same goal with minimal neck movement.
Once the airway is opened, suctioning may be necessary to remove secretions. Insertion of an artificial airway adjunct, such as an oropharyngeal or nasopharyngeal airway, can help maintain patency, particularly in patients with reduced consciousness. Securing a clear airway is foundational, as effective breathing cannot occur without it.
Evaluating Respiratory Function
The ‘B’ for Breathing is assessed after a patent airway is established, focusing on the quality and effectiveness of air movement. The nurse inspects the rate, rhythm, and depth of respirations; a normal range is typically 12 to 20 breaths per minute. Signs of respiratory distress include shallow breathing, rapid breathing (tachypnea), or the use of accessory muscles.
Auscultation helps identify abnormal breath sounds indicating underlying issues. Wheezing suggests lower airway narrowing, while crackles may point to fluid in the lungs (e.g., pneumonia or heart failure). Oxygen saturation, measured with a pulse oximeter, provides an objective reading of oxygen delivery; a reading below 94% often requires immediate attention.
Interventions center on improving oxygenation and ventilation. Supplemental oxygen is administered via nasal cannula or mask to raise saturation levels. If breathing is too slow or ineffective, assisted ventilation with a bag-valve-mask (BVM) device may be required. Proper positioning, such as semi-Fowler’s position, promotes better lung expansion and eases the work of breathing.
Ensuring Adequate Blood Flow
The ‘C’ for Circulation addresses the delivery of oxygenated blood to the body’s tissues. Assessment begins with a rapid check of the central pulse (e.g., carotid artery) to confirm the presence and strength of the heartbeat. The nurse observes skin color, temperature, and capillary refill time, which should normalize within two seconds. Pale, cool, or clammy skin and prolonged capillary refill indicate poor tissue perfusion.
Immediate control of major external hemorrhage is a life-saving priority that may precede airway management in trauma. Direct pressure must be applied to the bleeding site, and a tourniquet may be used for severe extremity bleeding. Uncontrolled bleeding can quickly lead to hypovolemic shock, where the body loses a significant volume of blood or fluid.
Signs of developing shock include a rapid heart rate (tachycardia), a drop in blood pressure, and altered mental status due to poor cerebral blood flow. Interventions include establishing intravenous (IV) access for the rapid administration of fluids, such as crystalloids, to restore circulating volume. Ongoing monitoring of vital signs and level of consciousness tracks the effectiveness of fluid resuscitation.
Expanding the Framework
While Airway, Breathing, and Circulation remain the systematic foundation for emergency assessment, the framework has evolved for specific clinical situations. One notable modification is the shift to C-A-B (Circulation, Airway, Breathing) during adult cardiac arrest and CPR. This change emphasizes starting chest compressions immediately to circulate remaining oxygenated blood, recognizing that rapid, high-quality compressions are the most time-sensitive intervention in this scenario.
In broader emergency and trauma care, the ABCs are often extended to form the ABCDE approach, providing a more comprehensive structure.
Disability (D)
The ‘D’ stands for Disability, which involves a quick neurological assessment. This often uses the AVPU scale (Alert, Verbal, Pain, Unresponsive) or includes checking blood glucose levels.
Exposure and Environmental Control (E)
The ‘E’ requires the nurse to fully expose the patient to check for hidden injuries or bleeding. Simultaneously, the nurse must prevent hypothermia by covering the patient after the examination. This expanded framework ensures a systematic approach that moves from immediate life threats to secondary conditions.