Bruce J. Sobol

Pulmonary function in ambulatory asthmatics

Abstract Sixty-one ambulatory and working asthmatic out-patients were studied at a time when they were free of acute exacerbation of their disease. Only one patient had entirely normal function and only seven patients had their function returned completely to normal by the administration of bronchodilator. These patients had the mildest impairment both in degree and number of abnormal functions. Their per cent improvement was no different than that of the other patients. Of the plethysmographic and spirometric functions tested, the maximal mid-expiratory flow was abnormal in the highest percentage of cases both before and after bronchodilator. On the other hand the percentage of subjects improving and returning to normal was highest for airway conductance and specific conductance. On the average the diffusing capacity was normal and there was no tendency for it to deteriorate with duration of disease. Likewise, there was no tendency for the other function tests to worsen with the duration of the asthma.

The breath-by-breath assessment of the response to bronchodilator☆

Abstract A method is presented for the continuous breath-by-breath assessment of airway resistance. This method is uniquely suitable for following the response to the administration of bronchodilator in patients with bronchial asthma. The method produces no discomfort and requires no special maneuvers on the part of the subject. The method consists of breathing into a nonobstructive flowmeter in series with a resistance of low value that is rapidly added and removed. The change in flow with the intrusion of the resistor permits calculation of the subjects respiratory resistance (the largest component of this being airway resistance). Sixteen studies were carried out on 8 subjects. In those subjects with a response to bronchodilator, this response was evident in 10 to 30 seconds following the administration of the bronchodilator.