Endotracheal lidocaine administration via an esophageal combitube

The purpose of this study was to test the hypothesis that lidocaine is syst emically absorbed after administration via a Combitube placed in the esopha gus, and that therapeutically significant plasma lidocaine concentrations c an be attained using this route with standard endotracheal doses (2.0 mg/kg ), During general anesthesia, 27 elective surgical patients received 2.0 mg /kg lidocaine (diluted as necessary with 0.9% saline to a minimum total vol ume of 10 mL) via a Combitube (study group, n = 13) or an endotracheal tube (control group, n = 14). Venous blood samples were drawn for 3 h after lid ocaine administration and plasma concentrations determined by gas chromatog raphy using a nitrogen-phosphorus detector (NPD), Overall, average Lidocain e concentrations were maximal after 5 min, reaching 0.8 +/- 0.7 and 1.7 +/- 0.7 mu g/mL in the Combitube and endotracheal tube groups, respectively. I ndividual patient peak concentrations averaged 1.0 +/- 0.7 and 2.2 +/- 1.1 mu g/mL in the same two groups, 19 +/- 16 and 10 +/- 15 min after lidocaine administration, respectively. No patients reported chest discomfort or dys pnea upon awakening, and no other side effects were noted. In support of th e hypothesis, administration of lidocaine via an esophageal Combitube resul ts in systemic drug uptake; however, at conventional endotracheal doses, pl asma concentrations are subtherapeutic. It remains to be determined whether higher doses of lidocaine administered via an esophageal Combitube will re sult in therapeutic plasma concentrations. (C) 2000 Elsevier Science Inc.