Use of Krypton-85 in the Study of Hypoxia in Porto-pulmonary Bilharziasis (schistosomiasis).

BRITS 1021 observations it was found that the immediate effect of the adrenergic drugs was similar. To obtain a measure of the duration of effect of the different inhalants, serial assessments were continued for three and a half hours after each inhalant therapy on two groups of asthmatic subjects containing 12 subjects in each group. From these serial studies it was found that the inhalants gave distinct time-response curves. The duration of isoprenaline was shortest; its action had been completely lost by 90 minutes. Adrenaline bitartrate and adrenaline hydrochloride combined with benzocaine were similar: a peak effect occurred at 15 minutes and was maintained up to 90 minutes, after which response gradually waned. Atropine methonitrate was found to have some immediate effect; the response reached a maximum at 90 minutes and was usually maintained throughout the three and a half hours of observation. The inhalation of isoprenaline in combination with atropine methonitrate showed substantial advantages over the other drugs tested. At 15 minutes the response was as good as the best isoprenaline response; it continued to improve for 120 minutes, after which it was maintained at this level during the three and a half hours of observation. It is recommended that the frequency of administration of atropine methonitrate with or without adrenergic inhalants should be strictly controlled, especially in acute asthma. We are indebted to the staff of the Department of Respiratory Physiology for carrying out the investigations described in this report, especially Mr. Porto-pulmonary bilharziasis often presents as hepatospleno-megaly and cor pulmonale (Zaky, 1952 ; Zaky et al., 1959). The haemodynamic changes in this disease have already been discussed (Foda, 1959; Zaky et al., 1962). We found that in about 10% of these cases hypoxia of less than 94% was present. This hypoxia could not be corrected by 100% 02 inhalation. When the alveolar CO2 tension was matched simultaneously against the arterial CO2 tension either at rest or on moderate exercise, a significant gradient was found between the alveolar Pco2 and the arterial Pco2, the latter being raised from 2 to 7 mm. Hg. Studies of pulmonary function in these cases revealed almost normal findings (Ashba, 1959), particularly the minute alveolar ventilation and the helium-mixing time. These findings can only mean a veno-arterial admixture either inside the lung from pre-capillary pulmonary-artery/pulmonary-vein shunting or from the portal-vein blood to the pulmonary vein. In order to elucidate the above findings it …