overventilation

overventilation /over·ven·ti·la·tion/ (-ven″tĭ-la´shun) hyperventilation.

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hyperventilation [hi″per-ven″tĭ-la´shun]

abnormally fast and deep breathing, the result of either an emotional state or a physiological condition. Emotional causes include acute anxiety and emotional tension, such as in nervous, anxious patients who may have other functional disturbances related to emotional problems. Physiological causes include a rapid decrease in intracranial pressure, other neurologic problems, and metabolic, pulmonary, and cardiovascular conditions. More prolonged hyperventilation may be caused by certain disorders of the central nervous system, or by drugs that increase the sensitivity of the respiratory centers (such as high concentrations of salicylates). Transient respiratory alkalosis commonly occurs when a person is hyperventilating. Iatrogenic hyperventilation may be seen in critically ill patients receiving mechanical ventilation.

It was formerly considered standard practice to hyperventilate patients following severe head injuries. However, now practice guidelines published by the American Association of Critical Care Nurses note that current research does not conclusively support this practice, and they urge judiciousness in its use. The Cochrane review is another study that notes that more clinical trials are required to determine the efficacy of hyperventilation in treatment of head trauma.

Symptoms of hyperventilation in the anxious patient include “faintness” or impaired consciousness without actual loss of consciousness. At the outset the patient may feel a tightness of the chest, a sensation of smothering, and some degree of apprehension. Other symptoms may be related to the heart and digestive tract, such as palpitation or pounding of the heart, fullness in the throat, and pain over the stomach region. In prolonged attacks the patient may exhibit tetany with muscular spasm of the hands and feet, and perioral numbness.

Short-term immediate treatment consists of having the patient slow the rate of breathing. Determining the underlying physical or emotional cause is necessary; the type of treatment depends on the cause. Medication, stress reduction measures, and controlled breathing exercises will control hyperventilation. Health care providers are no longer advised to use the technique of rebreathing into a paper bag, because of the danger of hypoxia.

hyperventilation syndrome a complex of symptoms that accompany hypocapnia caused by hyperventilation, including palpitation, a feeling of shortness of breath or air hunger, lightheadedness or giddiness, profuse perspiration, and tingling sensations in the fingertips, face, or toes. Prolonged overbreathing may result in vasomotor collapse and loss of consciousness. Hyperventilation that is unrecognized by the patient is a common cause of the symptoms associated with chronic anxiety or panic attacks.

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overventilation

hyperventilation.