Syncope (Table 1) is defined as sudden brief loss of consciousness due to cerebral ischemia. In a young adult it is usually precipitated by a generalized, progressive autonomic discharge secondary to anxiety, pain, heat, or humidity. The initial adrenergic response to a stressor is followed by an overwhelming cholinergic surge just prior to unconsciousness. Syncope in patients over 50 years of age may likely be secondary to cardiovascular disorders (e.g., dysrhythmia, postural hypotension), hypoglycaemia or cerebrovascular insufficiency.

Table 1. Syncope.

  • Identify at-risk patient
    • Reduce Stress
    • Treat patient in a supine position
    • Ensure profound local anaesthesia
      • Use local anaesthetic agents containing a vasoconstrictor congruent with the patient’s functional capacity
Signs and symptoms:
  • Adrenergic component
    • Anxiety
    • Pallor
    • Pupillary dilation
    • Palpitation
  • Cholinergic component
    • Diaphoresis (perspiration)
    • Nausea
    • Salivation
    • Bradycardia
    • Hypotension
    • Sudden, brief loss of consciousness
    • Seizure (rarely)
Emergency response:
  • Place patient in Trendelenburg position, i.e., head and chest slightly below a line parallel to the floor and feet slightly elevated (Figure 9)
    • Administer oxygen
      • 4 to 6 L/min by nasal cannula
    • Stimulate cutaneous reflexes
      • Cold towel compresses to forehead and back of head
      • Administer aromatic ammonia inhalant
    • Reevaluate vital signs
  • If patient’s condition deteriorates
    • Activate EMS
      • Monitor vital signs
        • If at any time the patient becomes unresponsive, no normal breathing, and no palpable pulse consider the diagnosis of cardiac arrest
          • Immediate CPR and defibrillation congruent with current recommendations

Illustration showing the Trendelenburg position.
Figure 9.
Nota bene:
  • Signs of recovery: vital signs return to baseline values, patient is alert
  • Signs of deterioration: vital signs unstable, mental status labile
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