[Sulpyrine inhalation challenge test monitored continuously by respiratory impedance and 81mKr ventilation image]

Continuous changes of respiratory impedance by the oscillation method using Asthograph and 81mKr ventilation image during saline and sulpyrine solution (100 mg/ml, 250 mg/ml) provocation were simultaneously measured in 15 adult asthmatics and 7 normal individuals. Estimation of airway obstruction by respiratory impedance using Asthograph was difficult during sulpyrine inhalation, since respiratory impedance increased gradually. In addition to the measurement of respiratory impedance, images of 81mKr ventilation were also obtained to estimate the regional ventilatory distribution. Estimation of the airway obstruction was easily obtained. Another advantage of 81mKr ventilation image is that it can estimate the regional ventilatory distribution. The site of airway obstruction provoked by sulpyrine was observed predominantly in the lower lung field. The results of our present study were as follows. 1) In 3 patient, increase of respiratory impedance and defect of 81mKr ventilation image were observed. Two cases in this group were clinically diagnosed as having aspirin-induced asthma. 2) In 7 patients, a defect of 81mKr ventilation image was observed, but no increase of respiratory impedance was observed. Five cases in this group could not be clinically diagnosed as having aspirin-induced asthma. 3) In 5 patients, neither defect of 81mKr ventilation image nor increase of respiratory impedance could be detected. These results suggest that 81mKr ventilation image on sulpyrine inhalation challenge test is a useful method for evaluating regional ventilatory distribution, but should be further investigated for application to aspirin-induced asthma.