ABCDE Assessment

The airway, breathing, and circulation, disability and exposure (ABCDE) assessment is the mainstay management approach used in managing critically ill patients. The ABCDEs are the essential 1st steps to perform in many situations including unresponsive patients, cardiac arrests, and critical medical or trauma patients. For the trauma patient, ABCDE is included in the primary survey, the initial evaluation, and management of injuries.

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Primary Survey

A primary survey is the initial evaluation used to identify and manage life-threatening injuries in a trauma patient.

The components of the primary survey are:

  • Airway
  • Breathing
  • Circulation
  • Disability
  • Exposure



  • Establish airway patency.
  • Assess the patient’s ability to protect the airway.
  • Manage the airway.
  • Spinal immobilization: using a backboard and rigid cervical collar

Causes of airway compromise

  • Traumatic injury
  • Patient’s tongue
  • Foreign body 
  • Vomit, blood, and secretions
  • Localized swelling due to infection or anaphylaxis

Airway assessment

  • If the patient can speak normally → airway is intact.
  • Signs of an unprotected airway:
    • Paradoxical chest and abdominal movements
    • Cyanosis
    • Abnormal breathing sounds:
      • Snoring
      • Stridor
      • Expiratory wheezing
      • Gurgling
    • Presence of an expanding hematoma
    • Presence of subcutaneous emphysema
    • Glasgow Coma Scale (GCS) < 9

Airway management

  • Adequate ventilation with 100% oxygen using a bag and mask
  • Pulse oximetry to monitor oxygen levels
  • Special maneuvers:
    • Chin lift, jaw thrust
    • Oral (oropharyngeal tube) or nasal (nasopharyngeal tube) airways can be used to temporarily maintain the airway 
  • If maneuvers fail, establish a definitive airway:
    • Endotracheal (orotracheal) intubation 
      • Insertion of a tube into the trachea through the mouth (less commonly the nose)
      • 1st-line procedure
    • Cricothyrotomy
      • Incision of the membrane between the thyroid cartilage and cricoid cartilage
      • Used if endotracheal in severe traumatic injuries, if intubation fails, or if airway is severely swollen (anaphylaxis!) 
      • Easier to perform than tracheostomy
      • Temporary procedure
    • Tracheotomy 
      • Incision to the trachea with insertion of a tracheal tube
      • Preferred in pediatric patients (age < 8) as the cricoid is much smaller


Breathing is the next step after the airway has been deemed adequate.


  • Detect signs of respiratory distress.
  • Maintain sufficient oxygenation and ventilation.
  • At this step, if breathing problems are found, it may be necessary to perform procedures (i.e., thoracostomy) to correct breathing issues found.

Breathing assessment

  • Listen to breath sounds.
  • Count respiratory rate:
    • 12–20/min is normal.
    • If respiratory rate is ↓ or ↑, consider airway assistance.
  • 40% of cardiac arrest patients may have agonal breathing (series of noisy gasps).

Signs of respiratory distress

  • Inspection: 
    • Central cyanosis
    • Jugular venous distention
    • ↑ effort needed to breathe
      • Use of accessory muscles
      • Abdominal breathing
  • Percussion: hyperresonance (pneumothorax) or dullness (hemothorax)
  • Palpation: tracheal shift, subcutaneous emphysema, flail segments
  • Auscultation: ↓ air entry during auscultation
  • Oxygen saturation < 88%
  • ↓ end-tidal CO₂ (capnography)

Breathing management

  • Depends on the cause
  • Return to A (airway) to establish definitive airway if there is respiratory distress.
  • Procedures for management of life-threatening breathing conditions:
    • Tube thoracostomy (small incision of the chest wall is made and a chest tube is inserted) is needed in:
      • Tension pneumothorax, open pneumothorax
      • Flail chest
      • Massive hemothorax
    • Pericardiocentesis (a needle and small catheter are inserted into the pericardial sac to drain excess fluid) is needed in cardiac tamponade.


Performed after the airway and breathing have been judged as normal and adequate.


  • Determine the effectiveness of the cardiac output.
  • Secure adequate tissue perfusion.
  • Treatment of external bleeding

Causes of poor circulation

  • Shock (including hypovolemia, septic, or anaphylactic shock)
  • Traumatic injury to arteries (compartment syndrome, arterial lacerations, crush injury)
  • Cardiac arrhythmias 
  • Heart failure 
  • Pulmonary embolism

Circulation assessment

  • Non-breathing (apneic) patients:
    • CPR (cardiopulmonary resuscitation) (function as artificial circulation)
    • Protect the spinal cord with cervical collar
  • Breathing patients:
    • Blood pressure assessment: indication of the effectiveness of the cardiac output, considered ↓ if systolic < 90 mm Hg
    • Measure heart rate by palpating the following arteries:
      • If carotid pulse is palpable → systolic pressure likely ≥ 60 mm Hg
      • If femoral pulse is palpable → systolic pressure likely ≥ 70 mm Hg
      • If radial pulse is palpable → systolic pressure likely ≥ 80 mm Hg
      • If dorsalis pedis pulse is palpable → systolic pressure likely ≥ 90 mm Hg
    • Check skin (cold, clammy skin is an indication of hypovolemia).
    • Check capillary refill time (abnormal greater than 2 seconds).
    • Check urinary output (< 0.5 ml/kg/h considered low).

Circulation management

  • Direct pressure to control any external hemorrhage
  • 2 large-bore IV lines to be placed in all patients; if not possible, alternatives include:
    • Central access into femoral, jugular, subclavian veins
    • Intraosseous access
    • Percutaneous and cutdown catheters in the lower limb saphenous vein (less common)
  • Consider mass transfusion blood protocol.

Disability and Exposure

Disability assessment

The goal of disability assessment is to determine and manage the presence of neurologic injury.

  • Examine pupils → pupil dilation suggests ipsilateral brain mass or blood collection, causing compression on the 3rd cranial nerve 
  • Motor and sensory examination
  • Assess level of consciousness and mental status through GCS:
    • Patient receives score for best response in each area.
    • Scores in each area are combined to reach a total score of 3–15.
    • ↑ the number → the better the prognosis
    • Score ≤ 9 indicates coma and patient needs endotracheal intubation.
  • Life-threatening neurological injuries include:
    • Penetrating cranial injury
    • Intracranial hemorrhage:
      • Subdural hematomas
      • Epidural hematomas
      • Traumatic subarachnoid hemorrhage
      • Intraparenchymal or intraventricular bleeding
    • Diffuse axonal injury
    • High spinal cord injury
Table: Glasgow Coma Scale
Eye openingOpen spontaneously4
Open to verbal command3
Open to pain2
No eye opening1
Verbal responseOriented and appropriate5
Disoriented but conversant4
Nonsensical words3
Motor responseFollows commands6
Localizes pain5
Withdraws to pain4
Flexor posturing3
Extensor posturing2


The goal of this step is to evaluate and manage negative environmental effects:

  • Completely undress the patient and carry out a full physical exam.
  • Keep the patient in a warm environment (hypothermia can trigger coagulopathies).

Secondary Survey

The goal of the secondary survey is to rapidly and thoroughly examine the patient from head to toe to identify all potentially significant injuries.

  • Performed after the primary survey and initial stabilization are completed
  • Examine patient from head to toe, including all orifices (ears, nose, mouth, vagina, rectum).
  • Order imaging as needed.
  • Go back to primary survey for reassessment frequently!

Clinical Relevance

The following are conditions that can cause acutely and severely impaired cardiovascular function in a patient:

  • Cardiac arrest: the loss of cardiac function in a person with or without known cardiac disease. The 4 cardiac rhythms that are known to produce a pulseless cardiac arrest are ventricular fibrillation, rapid ventricular tachycardia, pulseless electrical activity, and asystole. Treatment is with advanced cardiac life support (ACLS), which includes CPR and giving epinephrine. 
  • Flail chest: a condition that occurs when 3 or more contiguous ribs are fractured in 2 or more different locations. Marked by chest pain, tachypnea, hypoxemia, and paradoxical thoracic wall movement. Often, tube thoracostomy is needed, as the condition is associated with pneumothorax. Management includes oxygen supplementation, pain control, and positive pressure ventilation if respiratory failure presents.
  • Hemothorax: a collection of blood in the pleural cavity. The condition usually occurs following chest trauma, which leads to lung laceration or damage to intercostal arteries. Symptoms include shortness of breath and chest pain. Signs include hypotension, tachycardia, decreased air entry, tracheal deviation, and dullness on percussion. Management is by chest tube insertion.
  • Pulmonary contusion: a traumatic parenchymal lung injury. Patients present with tachypnea, tachycardia, and hypoxemia. Computed tomography scan shows patchy alveolar infiltrates not restricted by anatomical borders (non-lobar opacification). Management involves oxygen administration, pain control, chest physiotherapy, and mechanical ventilation in severe cases.
  • Pneumothorax: an abnormal collection of air in the pleural space. Physical exam findings include decreased breath sounds, hyperresonance on percussion, tracheal deviation, mediastinal shift (away from tension pneumothorax), decreased tactile vocal fremitus, and distended jugular veins. Chest X-ray, ultrasound of chest, and CT all can identify pneumothoraces. Treatment includes emergent needle decompression and thoracotomy.
  • Cardiac tamponade: an accumulation of fluid in the pericardial space, resulting in reduced ventricular filling and subsequent hemodynamic compromise. Cardiac tamponade is a severe form of pericardial effusion. In the setting of trauma, the effusion is blood. Physical examination findings include Beck’s triad (hypotension, jugular venous distention, and muffled heart sounds). Treatment is emergent pericardiocentesis.


  1. Advanced trauma life support (ATLS®): the ninth edition. J Trauma Acute Care Surg. 2013 May;74(5):1363-6. doi: 10.1097/TA. 0b013e31828b82f5.
  2. Sivilotti, M. Initial management of the critically ill adult with an unknown overdose. (2019). UpToDate. Retrieved November 22, 2020 from:
  3. Thim, T., Krarup, N. H., Grove, E. L., Rohde, C. V., & Løfgren, B. (2012). Initial assessment and treatment with the Airway, Breathing, Circulation, Disability, Exposure (ABCDE) approach. International journal of general medicine, 5, 117–121.

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