Endotracheobronchial lidocaine concentrations during flexible fiberoptic bronchoscopy (FFB)

Lidocaine concentrations in 49 endotracheobronchial aspirates ranged from 12,580 to 23 micrograms/ml. The aspirates taken from the larger airway contained higher concentrations of lidocaine than those obtained from the smaller airway. Of the aspirates collected before 10 minutes after the final lidocaine administration, the lidocaine concentration of 7 (24.1%) of 29 specimens was greater than 3,000 micrograms/ml, however, in the aspirates collected after 10 minutes, only 1 (5%) of 20 specimens showed a concentration greater than 3,000 micrograms/ml. Using the dilution technique method (DTM) of lidocaine in the fiberscope (FS) suction channel, gradual injection of a 2 ml saline solution into the suction channel and removal of the saline solution in the suction channel were performed immediately with a suction machine; the statistically significant differences (p < 0.001) between lidocaine concentrations in the specimens before and after the DTM procedure were determined.