Serum lidocaine levels in patients undergoing fibrobronchoscopy

Serum lidocaine levels were determined in 29 patients undergoing fibrobronchoscopy after drug doses ranging from 180 to 400 mg. The results showed rapid absorption of the anaesthetic by the tracheobronchial mucosa with an average absorption constant of 4.77 +/- 1.99 h-1. Maximum lidocaine levels in serum averaged 1.21 +/- 0.64 microgram/ml, lower than the levels established as toxic for this anaesthetic. The serum half-life of lidocaine averaged 1.55 +/- 0.72 h. The percentage of dose absorbed in this kind of patient ranged between 20.89 and 60.88% of the dose administered.