Hyperventilation Syndrome Diagnosis and Management

Definition and Causes

The European Society of Cardiology guidelines state that hyperventilation syndrome symptoms are "much closer to panic attacks than to syncope" and that there is insufficient evidence to recognize "hyperventilation syncope" as a specific clinical entity, with symptoms characterized by breathing in excess of metabolic needs, resulting in respiratory alkalosis and hypocapnia 1, 2, 3
The syndrome is most commonly associated with anxiety disorders, panic attacks, and psychological stress, according to the American Thoracic Society 4

The core mechanism involves breathing in excess of metabolic needs, eliminating more CO2 than is produced, resulting in respiratory alkalosis and elevated blood pH, with the European Society of Cardiology noting that hyperventilation's effect on circulation is paradoxical 1, 2, 3
Cerebral vasoconstriction occurs, reducing cerebral blood flow, though the net circulatory effect is complex 1, 2, 3

The diagnosis is one of elimination, requiring documentation of hyperventilation with low PaCO2, exclusion of organic diseases causing hyperventilation, and identification of complaints related to hypocapnia, with the American Thoracic Society recommending arterial blood gas analysis 4
Cardiopulmonary exercise testing can reveal characteristic breathing patterns and Ve/VCO2 abnormalities with simultaneous arterial PCO2 sampling 4

The therapeutic approach has three escalating stages, chosen based on severity, including psychological counseling, physiotherapy and breathing retraining, and pharmacotherapy 4
The American Thoracic Society notes that identification of hyperventilation syndrome is crucial because appropriate treatment is usually successful, with over 70% of patients able to be "cured" with simple therapeutic measures 4

Absolute contraindications to diagnostic hyperventilation provocation testing include recent stroke, significant carotid stenosis, recent intracranial hemorrhage, Moyamoya disease, sickle cell disease or trait 6
Relative contraindications include increased intracranial pressure, severe cardiac conditions, severe pulmonary disease, and late-term pregnancy 6