Selective sputum cultures. A bronchial culture technique using a modified nasotracheal suction catheter with a sterile, inner telescoping cannula.

The contamination of expectorated or catheter-aspirated sputum specimens by pathogenic microorganisms which have colonized the nose and oropharynx remains a formidable obstacle to the accurate interpretation of sputum cultures. This problem is encountered in all forms of acute and chronic bronchopulmonary infection. A standard suctioning technique via a nasotracheal catheter has been modified with a telescoping sterile inner cannula to obtain uncontaminated bronchopulmonary secretions for culture. Bacteriologic results of selective bronchial cultures obtained in 18 patients following major chest surgery have provided important considerations concerning the prophylactic use of antibiotics. The telescoping cannula method is a simple, safe, and practical means of selectively monitoring the bacteriologic flora of the lower respiratory tract.