An Aerosol Method of Producing Bronchial Secretions in Human Subjects: A Clinical Technic for the Detection of Lung Cancer

¹ The Columbia University Research Service, Goldwater Memorial Hospital, the Department of Medicine, College of Physicians and Surgeons, Columbia University, and the Presbyterian and Francis Delafield Hospitals.

A method of obtaining sputum from the respiratory tract of "normal" individuals, patients with chronic non-tuberculous pulmonary disease, and patients with known or suspected malignancy is reported. The basis of this procedure involves the inhalation of warm, hygroscopic saline aerosols.

Approximately 10 ml. of a 10 or 15 per cent saline aerosol containing 20 per cent propylene glycol was administered to a total of 336 subjects. Mucoid sputum specimens suitable for cytologic examination were recovered in 88.5 per cent of the entire series. Of special interest as a possible screening technic for the cytologic diagnosis of lung cancer was the production of sputum in 86 per cent of 180 subjects who had no evidence of pulmonary disease, and no cough or spontaneous sputum. Only three subjects in this group noted a slight irritation on inhaling the warm 10 per cent saline aerosol.

Cytologic studies of the sputum recovered from 74 subjects following the inhalation of 10 per cent saline showed that 79 per cent of the specimens were satisfactory for diagnosis. In five of the eight patients with documented primary or metastatic carcinoma in the lung, sputum preparations were positive for malignant cells. There were no false negative reports. Since all of the examinations were performed on single specimens, it is evident that cytologic study of repeated specimens obtained in a similar manner might increase the possibilities of accurate diagnosis. It is the opinion of our cytologist (E. E. S.) that this method of inducing sputum may be expected to demonstrate tumor cells from symptomless individuals before spontaneous sputum arises since the specimens obtained by hypertonic saline aerosol are entirely adequate for study.

Inhalation of nebulized 20 per cent propylene glycol at a temperature of 120°F. is employed to facilitate expectoration of retained secretions in patients with bronchopulmonary disease.