ABCDE approach

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The ABCDE approach is an almost universally applicable strategy for the initial assessment and resuscitation of critically ill patients. Systems are evaluated and managed simultaneously in the order of their potential threat to the patient's survival: airway, breathing, circulation, disability, and exposure. As a first priority, airway patency is assessed and secured as needed (e.g., using basic airway maneuvers or intubation). Breathing is often evaluated concurrently and treated with respiratory support (e.g., oxygen therapy, bag-mask ventilation, mechanical ventilation) as well as specific time-sensitive therapy (e.g., bronchodilators, chest tubes). The next priority is circulatory assessment and initiation of immediate hemodynamic support (e.g., IV fluid therapy, vasopressors) as needed. A rapid neurological assessment should be prioritized next to identify reversible or time-sensitive causes of altered mental status (e.g., hypoglycemia, intracranial bleed), seizures, weakness, or other focal neurological deficits. The final priority is rapid exposure of the patient's body to identify potentially hidden clues to the underlying cause (e.g., rashes, transdermal medication patches) and remove any inciting or aggravating factors (e.g., allergens, contaminated or wet clothing). For each priority, lifesaving treatment should be initiated without delay, even if a definitive diagnosis has not been established. To ensure optimal outcomes, a team of appropriately trained staff should be assembled as early as possible, and team management should ideally follow the principles of crisis resource management (CRM). Following initial stabilization, a secondary survey including a thorough history and examination is initiated and, if necessary, the patient is prepared for transport or handed off to the appropriate specialty service.

See “Management of trauma patients” for the ABCDE approach as applied in patients with acute injuries.

Clinical applications ^[2][3]

• The ABCDE approach can be applied to any situation where a quick assessment and initiation of lifesaving treatment may be necessary, e.g., in emergency departments, critical care units, wards, and prehospital environments.
• Any potentially critically ill or unstable patient can initially be managed with this approach until they are stable enough for further diagnostics and treatment.
• The ABCDE approach should not be used for patients in cardiac arrest.
  • If a patient is unresponsive, assess for cardiac arrest, call for help, and initiate resuscitation.
  • For further information, see “Advanced Cardiac Life Support.”

The ABCDE approach can be used for the initial assessment and management of all potentially unstable patients.

In patients with cardiac arrest, initiate CPR immediately.

Core concepts

The ABCDE approach consists of a rapid (< 10 minute) framework to assess and manage critically ill patients by prioritizing conditions with the greatest risk to their survival. ^[4]

• In clinical practice, assessments and interventions for each component are often undertaken simultaneously by multidisciplinary teams.
• A definitive diagnosis or detailed history is not essential for the initiation of lifesaving treatment if there is a sufficiently high level of suspicion.
• The ABCDE assessment is regularly repeated in order to:
  • Assess the efficacy of interventions, e.g., supplemental O₂, intubation, or treatment of hypoglycemia
  • Detect further deterioration early

Assess and treat conditions in order of the greatest potential threat to patient survival, and always anticipate potential deterioration.

Significant information on the ABCDE assessment can be gained by simply asking the patient to state their name and reason for seeking care. A coherent answer affirms momentary airway patency, the minimum ventilatory and circulatory reserves required for brain perfusion, and an adequate neurological status.

Crisis resource management (CRM) ^[5][6]

• The concept of CRM outlines several strategies to improve teamwork and patient outcomes in emergency situations.
• CRM emphasizes effective leadership, communication, and situational awareness in multidisciplinary team settings.

Closed-loop communication: Repeat received messages and announce the completion of tasks.

For a quick handoff, summarize SBAR: Situation, Background, Assessment, Recommendation.

• Airway and breathing are typically assessed simultaneously to identify concurrent problems and predict deterioration.
• Airway obstruction can be partial or complete and may be caused by processes in the upper airways or a reduced level of consciousness.
• For further information, see “Airway management.”

• Prerequisites for adequate spontaneous ventilation include : ^[9]
  • A patent airway
  • Intact chest wall, lungs, diaphragm
  • Sufficient muscle strength
  • Intact central respiratory drive
  • Adequate pulmonary circulation
• Airway and breathing are typically assessed simultaneously.
• Advanced airway devices are required for invasive mechanical ventilation.
• For further information, see “Respiratory failure”, “Oxygen therapy” and “Mechanical ventilation.”

• Shock, hypertensive crises, cardiac dysrhythmias, acute coronary syndromes, and vascular emergencies (e.g., aortic aneurysms, aortic dissection) can be a threat to patient survival.
• End-organ damage in shock leads to:
  • Multiorgan dysfunction and cardiac arrest
  • Respiratory failure due to fatigue
  • Hypoxic-ischemic encephalopathy and brain death due to cerebral hypoperfusion
• Hypertensive crises can also cause end-organ damage, including:
  • Cardiorespiratory failure due to, e.g., pulmonary edema, aortic dissection, or myocardial infarction
  • Primary and secondary brain injury due to hemorrhagic stroke and/or hypertensive encephalopathy

In a patient with tachycardia and cold extremities, assume shock. If there are no clinical signs of fluid overload or evidence of cardiogenic shock, begin immediate fluid resuscitation.

• An abnormal neurological status may be caused by:
  • Primary brain injury (e.g., stroke, TBI, status epilepticus)
  • Systemic conditions (with or without secondary brain injury): see “Causes of AMS and coma.”
• Preventing and treating brain injury requires adequate oxygenation and cerebral perfusion.
• For further information, see also:
  • “Secondary brain injury and neuroprotective measures”
  • “ABCDE approach: toxicology-specific considerations”

Remember AVPU to assess the level of consciousness: Alert, Voice responsive, Pain responsive, Unconscious.

Consider securing the airway in patients with decreased consciousness.

Exposure involves a rapid whole-body inspection to avoid missing signs or injuries that impact management.

Do not forget to examine concealed and frequently overlooked areas, e.g., the back, the orifices, the axillary, inguinal, and perineal regions, and body parts underneath surgical dressings.

After initial stabilization, proceed to the secondary survey and, if necessary, prepare the patient for handoff to another specialty or interfacility transfer.

• Assessment and management: Can switch to the standard approach used for noncritically ill patients.
  • Obtain a thorough patient history.
  • Perform a full physical examination.
  • Order or perform relevant diagnostic tests as guided by clinical assessment.
  • Begin critical targeted treatments and ensure adequate supportive care.
  • Obtain consults as needed.
  • Consider the need for specialized care and whether an interfacility transfer is required.
• Interfacility transfer planning (as needed)
  • Ensure there is an adequate handoff with the receiving physician.
  • Prepare copies of relevant medical records and imaging.
  • Determine the level of care needed for transfer.
  • Ensure the patient is stable and try to anticipate and prevent problems during transport. ^[9]
    • Ensure secure IV access, e.g., by placing an additional peripheral IV line or establishing central venous access.
    • Place a nasogastric tube in patients with a high risk of aspiration, e.g., due to bowel obstruction.
    • Intubate patients at high risk of losing airway patency.
    • Anticipate and prepare any medication that might be required en route, e.g., vasopressors, benzodiazepines for seizures.

If there is any deterioration in patient status during the secondary survey, return to ABCDE assessment immediately!

Most critically ill patients require cardiorespiratory monitoring, IV access, and supplemental O₂ as minimum initial measures during the ABCDE survey.