Also found in: Dictionary, Thesaurus, Encyclopedia.


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.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.


Increased alveolar ventilation relative to metabolic carbon dioxide production, so that alveolar carbon dioxide pressure decreases to below normal.
Synonym(s): overventilation
Farlex Partner Medical Dictionary © Farlex 2012
References in periodicals archive ?
In mild climates (such as the coast of California) infiltration alone is not enough to provide adequate ventilation in newer well-insulated homes, while in harsher climates, infiltration rates may be so high as to cause overventilation, energy loss, and comfort issues due to drafts.
Contrary to popular belief, improved humidity control can actually lower energy use where overventilation or over-cooling is the underlying cause.
The reason for overventilation in the critical zone is the fact that the outdoor air fraction determined by MSE strategy considers full occupancy in the overall system.
Most systems installed today are not DOAS (the sole focus of the article), and the 30% overventilation credit in LEED drives designs with both energy and moisture problems in commonly used systems.
Joseph Lstiburek's November 2008 "Why Green Can Be Wash" column, which stated that overventilation just to get a LEED credit is not a sustainable practice.
The Building Sciences column "Why Green Can Be Wash" in the November 2008 ASHRAE Journal addressed overventilation this way, "Do you want to save serious energy and serious money?
The only possible thing that can screw up the performance is overventilation. ([section])
I repeat, once again, overventilation does not make a building "greener.
And, much to my chagrin, the latent load has increased due to overventilation. The old systems can't handle the new sensible to latent ratios.