The technique of endobronchial lidocaine administration does not influence plasma concentration profiles and pharmacokinetic parameters in humans.

This study investigated plasma concentration profiles, pharmacokinetic characteristics and side-effects of lidocaine following 3 different administration techniques. Sixty ASA I/II patients undergoing elective ENT-operations were randomised into 4 groups. Lidocaine 1% (1 mg/kg) was administered 50 min before the end of the operation, via a regular endotracheal tube (group 1), a suction-catheter deep endobronchially (group 2), or an EDGAR-(Endobronchial-Drug and Gas Application during Resuscitation)-tube characterized by a separate injection channel ending at the orifice of the tube (group 3). For the control group, a regular endotracheal tube was inserted without lidocaine administration (group 4). Anesthesia was induced with propofol (2 mg/kg), sufentanil (0.5 micrograms/kg), and vecuronium (0.08 mg/kg) and continued as total intravenous anesthesia with propofol (8 mg/kg/h) and oxygen in air (FiO2 = 0.33). A control and 13 blood samples were taken up to 180 min after lidocaine administration. Lidocaine plasma concentrations were determined using a fluorescence polarization immunoassay (TDxFLx). Heart rate, blood pressure, endtidal PcO2, and oxygen saturation were similar in all groups investigated. Ventilation was interrupted for 3.6 +/- 0.5 s in group 1 and 10.2 +/- 0.8 s in group 2, to administer lidocaine. Patients from group 3 were ventilated continuously because of a separate injection channel integrated in the EDGAR-tube. Sore throat was significantly increased in group 2 as compared with groups 1, 3 and 4. Asorption of lidocaine in groups 1-3 resulted in maximal mean plasma concentrations ranging from 0.78 to 0.85 micrograms/ml after 16.9 to 22.4 min.(ABSTRACT TRUNCATED AT 250 WORDS)