[Serum concentration of lidocaine and its active metabolite monoethylglycinexylidine during fiberoptic bronchoscopy under local anesthesia].
Fiberoptic bronchoscopy was performed in local anaesthesia with lidocaine in 16 patients. Serum concentrations of lidocaine and its active metabolite monoethylglycinexylidide (MEGX) were measured at regular intervals up to 120 min. after administration. Lidocaine was administered as aerosol in the upper respiratory tract and as solution in the bronchial tree. The total lidocaine dose was 243-608 mg (2.4-8.0 mg/kg); 163-508 mg (1.6-6.6 mg/kg) was given as aerosol, and 60-180 mg (0.8-2.5 mg/kg) as solution. The highest median S-lidocaine concentration, 10.5 mumol/l, was measured 20 min. after administration. None of the patients had toxic S-lidocaine levels (greater than 26 mumol/l) and no adverse effects were observed. The highest median S-MEGX concentration, 1.7 mumol/l, was measured 120 min. after administration. The highest individual S-MEGX was 3.5 mumol/l. The highest, although insignificant, correlation coefficients were found between lidocaine dose expressed in mg/kg body weight and S-lidocaine and S-MEGX.