Abnormally deep or rapid breathing that is usually caused by anxiety. Hyperventilation may also occur as a result of uncontrolled diabetes mellitus, oxygen deficiency, kidney failure, and some lung disorders.
Hyperventilation causes an abnormal loss of carbon dioxide from the blood, which can lead to an increase in blood alkalinity. Symptoms include numbness of the extremities, faintness, tetany, and a sensation of not being able to take a full breath. Breathing into a paper bag may help to reduce the symptoms in people with anxiety.
An abnormally rapid resting respiratory rate (see RESPIRATION). If voluntarily induced, it causes lightheadedness and then unconsciousness by lowering the blood tension of carbon dioxide.
Hyperventilation is a manifestation of chest and heart diseases which raise carbon dioxide tension or cause HYPOXIA (e.g. severe CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) or PULMONARY OEDEMA). Mechanically ventilated patients may be hyperventilated to lower carbon dioxide tension in order to reduce INTRACRANIAL PRESSURE. (See also HYPOCAPNIA.)
n. breathing at an abnormally rapid rate at rest. This causes a reduction of the carbon dioxide concentration of arterial blood, leading to dizziness, tingling (paraesthesiae) in the lips and limbs, tetanic cramps in the hands, and tightness across the chest. If continued, hyperventilation may cause loss of consciousness. This sequence of events occurs in the hyperventilation syndrome (HVS), which has been estimated to contribute to 10% of out-patient referrals to hospital.
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