Hyperventilation Syndromes

Key Features

• Hyperventilation is an increase in alveolar minute ventilation leading to hypocapnia

• Causes include

  • Pregnancy

  • Hypoxemia

  • Obstructive and infiltrative lung disease

  • Sepsis

  • Hepatic dysfunction

  • Fever

  • Pain

• "Central neurogenic hyperventilation" describes monotonous, sustained deep breathing seen in comatose patients with brainstem injury

Clinical Findings

• Acute hyperventilation

  • Hyperpnea

  • Anxiety

  • Paresthesias

  • Carpopedal spasm

  • Tetany

• Chronic hyperventilation presents nonspecifically

  • Fatigue

  • Dyspnea

  • Anxiety

  • Palpitations

  • Dizziness

Diagnosis

• Symptoms must be reproduced during voluntary hyperventilation

Treatment

• When organic causes have been excluded, breathing through pursed lips or through the nose with one nostril pinched, or rebreathing expired gas from a paper bag decreases respiratory alkalemia and its symptoms

• Anxiolytics may be helpful