Abstract
Antimicrobial activity of lidocaine solution was studied as a part of the serial transtracheobronchial microbiological culture study using the flexible fiberoptic bronchoscope (FS). Six clinical strains including, E. coli, K. pneumoniae, Ps. aeruginosa, S. marcescens, S. aureus and Str. hemolyticus were used for this study. The colony count of these microorganisms ranged from 106 to 1010/ml.
The antimicrobial activity of lidocaine solution was at a concentration of 3, 000 μg/ml or more, and this inhibitory activity was proportional to the lidocaine density. And at a concentration of 8, 000 to 24, 000 μg/ml or more, it changed to bacteriocidal, so possibly a small amount, say one or two per cent lidocaine solution, should be used instead of the 4% lidocaine solution. As soon as the microbial specimens are taken, they should be cultivated as quickly as possible.
The dilution technique method (DTM) of lidocaine in the FS suction channel, with gradual injection of a 2 ml saline solution into the suction channel and removal of the solution in the suction channel were performed with a suction machine. This is one more important procedure. The procedure showed statistically significant differences (P<0.001) of lidocaine concentrations in the specimens before and the after DTM procedure were proven.
