Bulletin de physio-pathologie respiratoire最新文献

The mechanical and the diffusing lung properties have been measured in 19 cases of diffuse fibrosing alveolitis of unknown etiology (proved by histology in 17 cases). The characteristic findings are: a) a striking reduction of DLCO in all the cases; b) a marked reduction of the static and dynamic compliance, in correlation with the reduction of vital capacity; c) an increase in P1max in correlation with the decrease of FRC; d) an increase of the elastic recoil when it is considered at various percentages of the predicted lung volume, but in some cases a normal shape of the V-P curve if the measured lung volume is taken into account; e) a reduction of the maximum expiratory flows suggesting bronchiolar stenosis; f) alterations of DL more marked than those of CL suggesting that DL is a more sensitive test.

The effects on hemoglobin oxygen transport of acute respiratory acidosis have been studied in dogs inhaling a gaseous mixture with 12% CO2 (O2 21%) for two to five hours. In a first series of experiments, it was shown that the shape of the oxyhemoglobin dissociation curve (ODC) was not modified by severe acidosis (pH congruent to 7) lasting for two and a half hours. The Hill number (N equals 2.6) did not change significantly. The aim of the second experimental series was to stuey the Bohr effect and the hemoglobin oxygen affinity (P50). The control value for the respiratory Bohr coefficient (B) was --0.54; neither after two hours (--0.52), nor after five hours of hypercapnia (--0.55) was it significantly modified. The P50 expressed at arterial pH was much increased in acidosis (congruent to 45 torr); when expressed at standard p/ 7.4, it was slightly but significantly decreased (congruent to 1 torr) at the fifth hour. At the same time there was a decrease (p smaller than 0.05) in the erythrocyte 2,3-DPG approaching 15 p. cent; on the other hand the ATP concentration did not change significantly. No significant individual correlation was found between P50(7.4), 2,3-DPG and mean hemoglobin corpuscular concentration. These results suggest that during severe respiratory acidosis neither a change in the shape of ODC, nor a change in Bohr effect do affect the hemoglobin oxygen transport. The main characteristic remains the decrease in oxygen affinity of hemoglobin, due to the erythrocyte [H+] increase induced by hypercapnia ; this phenomenon is observed as long as the 2,3-DPG decrease stays moderate.

In a group of 26 patients with various broncho-pulmonary diseases, the results of three types of exercise were compared : maximum supported power (PMS), maximum supported power + 20 W, and maximum tolerated power (PMT). The two first ones were made at constant power, the last one at increasing power (by 30 W, during three minutes). The comparison of the results indicates that there was no significant difference between the variables measured during PMT and PMS +20 W (power, oxygen uptake, cardiac frequency, oxygen pulse, ventilation). The changes in oxygen uptake, cardiac frequency, and ventilation, as the power increased, were not significantly different in the three types of exercise. In this group of patients, mean PMT was 121 W, mean PMS was 98 W, and the ratio PMS/PMT was thus 81%. To determine PMT first reduced the number of exercise-tests necessary to measure PMS (two or three tests depending on the patient).