Sputum induction: review of literature and proposal for a protocol

Abstract

Since the 1980s, sputum induction by inhalation of hypertonic saline has been successfully used for diagnosing Pneumocystis carinii pneumonia in patients infected with HIV. In recent years, sputum induction and its subsequent processing has been refined as a noninvasive research tool providing important information about inflammatory events in the lower airways, and it has been used for studying various illnesses. In asthma, one application is to use sputum inflammatory indices to increase our understanding of complex relationships between inflammatory cells, mediators, and cytokine mechanisms. In chronic obstructive pulmonary disease, sputum assessment could be used as a screening test before deciding on long-term corticosteroid treatment. In tuberculosis, sputum induction is a valuable diagnostic tool for HIV-seropositive patients who do not produce sputum. Sputum induction appears to be a relatively safe, noninvasive means of obtaining airway secretions from subjectswith cystic fibrosis, especially from those who do not normally produce sputum. Moreover, sputum induction can also be used in chronic cough and lung cancer. Generally, induction is performed through ultrasonic nebulizers, using hypertonic saline. It is recommended that sputum be processed as soon as possible, with complete homogenization by the use of dithiothreitol. We have also shown in this article an example of a protocol for inducing and processing sputum employing a nebulizer produced in Brazil.

Determining Cystic Fibrosis-Affected Lung Microbiology: Comparison of Spontaneous and Serially Induced Sputum Samples by Use of Terminal Restriction Fragment Length Polymorphism Profiling

“…SI samples are both safe and noninvasive (5,21) and as such have a proven potential for analysis of nonproductive airway conditions, such as asthma, COPD, and nonproductive, pediatric CF remains (37). However, the data presented in this study suggest that single SI samples do not provide a clear advantage over SES samples in the study of productive respiratory infections, such as those associated with CF.…”

Safety and tolerability of sputum induction in adolescents and adults with suspected pulmonary tuberculosis

“…We selected this approach because we were investigating the feasibility of the induced sputum procedure in a setting where lung function measurement is not readily available, and because all participants received salbutamol pre-treatment, which would have significantly lowered the risk of subsequent bronchospasm. The sputum induction procedure is not standardized and there are variations in the procedure that could affect the generalizability of our findings to other populations (Y. Gonzalez of solution in the nebulization chamber, the type of nebulizer, and participant characteristics [10,19,20]. We used 5% saline, in a volume of 30 ml, with nebulization via high-flow 100% oxygen.…”

Supervised and induced sputum among patients with smear-negative pulmonary tuberculosis

“…First, induced sputum significantly outperformed supervised sputum. It is probable that hypertonic saline works by improving sputum transportability, enhancing mucociliary clearance and inducing cough [24,25]. Secondly, by adding one specimen each of supervised and induced sputum to two unsupervised specimens the culture yield was significantly increased.…”