Comparison of effects of thoracic epidural and intravenous administration of lidocaine on target-controlled infusion of propofol and tracheal intubation response during induction of anesthesia.

OBJECTIVE

To compare the effects of thoracic epidural anesthesia (TEA) and intravenous (IV) lidocaine on the effect-site concentration (Ce) of propofol target-controlled infusion (TCI) and the intubation-induced stress responses during general IV anesthesia induction.

DESIGN

A prospective, randomized trial.

SETTING

A university hospital.

PARTICIPANTS

Sixty patients undergoing elective surgery for thoracotomies.

INTERVENTIONS

Patients scheduled for thoracotomies were divided into 3 groups as group TEA, group IV, and control group. Group TEA or group IV received the same doses but not the same concentration of lidocaine via TEA (0.15 mL/kg of 1.35% lidocaine) or IV (2mg/kg of 2% lidocaine), respectively, 15 minutes before induction of anesthesia, and the control group received the same volume of 0.9% normal saline epidurally.

MEASUREMENTS AND MAIN RESULTS

Heart rate and mean arterial pressure as well as the time to loss of consciousness (LOC), total doses of propofol TCI, and Ce at LOC were recorded during anesthesia induction. Plasma lidocaine concentration detected was 1.9 (0.3) μg/mL in the IV group and 1.0 (0.3) μg/mL in the TEA group (p<0.001). The time to LOC, total doses of propofol TCI, and Ce at LOC were significantly lower in the IV group than in the TEA group and the control group (p<0.001). Both lidocaine groups showed significant decreases in the elevation of mean arterial pressure and heart rate and plasma concentrations of epinephrine and norepinephrine induced by intubation compared to the control group (p< 0.05).

CONCLUSION

Lidocaine administered via both TEA and IV decreased the induction doses of propofol and suppressed cardiovascular and stress responses to tracheal intubation. Administration of 2mg/kg of 2% lidocaine IV was better, with no side effects of lidocaine toxicity.