[Simultaneous recording of nonspecific bronchial response using continuous measurement of total respiratory resistance and oxygen saturation of arterial blood].

In 78 patients with bronchial asthma symptoms undergoing nonspecific bronchial response test with bronchoprovocation inhalation of progressively increased methacholine concentrations, total respiratory resistance (Rrs) and oxygen saturation (SaO2) of arterial blood were continually measured. An average Rrs increase was 153% when compared to the initial values and it correlated with SaO2 decrease (5.5% of the initial values). In 45 patients along with continual Rrs and SaO2 measurements, bronchoprovocation test and spirogram flow-volume curve were periodically done. Ten of these patients had no significant Rrs or FEV1 changes, but there was a considerable drop in FEF50, FEF25 and SaO2. These results, associated with dyspnea and physical pulmonary findings in the course of BPT, as well as history of patients with similar difficulties in every-day life and in work environment, point to the need of expanding diagnostic criteria for positive BPT and for patients who did not have Rrs increased double the initial values nor sufficient FEV1 20% drop. Spirometry and oximetry as complementary methods, increase Astograph sensitivity to methacholine test. Oximetry has an advantage of enabling continual SaO2 monitoring and increased patient's safety during the BPT.