| abstract |
Early detection of lung dysfunction, which in HIV positive patients usually indicates PCP pneumonia infection, is accomplished by a CO fractional uptake test which includes supplying air containing 0.1% CO into a gas reservoir or regulator from which it is drawn through a non-rebreather valve into a mouthpiece and inhaled into the lungs of a patient. Exhaled air is directed by the non-rebreather valve into a chamber coupled to a gas inlet of an infrared CO analyzer. An end tidal volume of gas last exhaled by the patient is drawn through the CO analyzer which measures the concentration of CO therein. The concentration of CO in the air from the gas reservoir also is measured. The fractional uptake of CO is computed as a function of the patient's breathing rate and the minute volume and compared with a stored baseline value for the patient to determine the presence of or extent of lung dysfunction. |