Graduation Year


Document Type




Degree Granting Department

Public Health

Major Professor

Stuart Brooks MD.


Sputum, Induction, IOS, Spirometry, Methylene blue


Sputum induction by inhalation of hypertonic saline has been used for more than15 years. It has become one of the most intriguing methods to study airway inflammation. It is the only direct, non-invasive method for measuring airway inflammation indices.Sputum induction has been used in the diagnosis of many respiratory illnesses including asthma, chronic pulmonary obstructive disease, tuberculosis, chronic cough, lung cancer and Pneumocystis Carinii on patients who are unable to produce sputum spontaneously.There are currently many different methods used worldwide to induce sputum, but there is a lack of one generally accepted gold standard method.The proposed protocols for sputum induction proved to be safe, simple and produced satisfactory amount of expectorate. However, it did not contain enough cells from the lower respiratory tract and was contaminated by squamous cells when compared to another method based on the work of F. E. Hargreave.

Investigation demonstrated that the use of impulse oscillometry, which requires no effort from patients, needs further research with larger study samples before it could be used instead of spirometry to evaluate airway obstruction.Initial methylene blue stain of the fresh expectorate smear was shown to be useful tool for identifying grossly contaminated sputum samples by squamous epithelial cells.Our first study group included 20 volunteers in good health. Sputum was induced by inhalation of 3% saline mist created by ultrasonic nebulizer at maximum output (4ml/min). Sputum induction intervals lasted 4-5 minutes with cumulative duration of induction about 4-15 minutes which was tolerated well. Lung function was evaluated for obstruction at baseline and every 5 minutes with spirometry and impulse oscillometry.The whole expectorated sample was processed and slides were stained with HEMA 3stain. With this method we were able to collect a mean of 6.1 ml expectorate.