In an investigation of a rapid screening test for airway reactivity using isocapnic hyperventilation with room air and cold air the results of this test were compared with the airway response to histamine and methacholine challenge. Twelve non-atopic, non-smoking normal subjects and 11 subjects with stable asthma who had an FEV1 above 74% of the predicted value were studied. In the normal subje...

TO THE EDITOR: In the context of a discussion about a patient with chronic obstructive pulmonary disease (COPD), a secondyear medical student recently asked: What is the definition of hyperventilation? My initial response was that, when the CO2 production rate is constant, an individual who is hypocapnic (i.e., has a lower than normal CO2 tension in arterial blood) must have hyperventilated. Th...

BACKGROUND To shorten emergence time after a procedure using volatile anesthesia, 78% of anesthesiologists recently surveyed used hyperventilation to rapidly clear the anesthetic from the lungs. Hyperventilation has not been universally adapted into clinical practice because it also decreases the Paco2, which decreases cerebral bloodflow and depresses respiratory drive. Adding deadspace to the ...