Tracheal lidocaine attenuates the cardiovascular response to endotracheal intubation

In order to examine the efficacy of tracheal lidocaine (TL) for attenuation of the cardiovascular responses to endotracheal intubation (EI), we compared the cardiovascular responses to TL alone and EI with TL, with those to EI without TL.

Seventy-five patients (ASA I-II) were studied. Anesthesia was induced with fentanyl 2 microg x kg(-1) iv, thiamylal 5 mg x kg(-1) iv and sevoflurane 1.0% in oxygen. Vecuronium 0.12 mg x kg(-1) was used to facilitate EI. In Group A (n=25), three minutes after induction, EI was performed. In Group B (n=25), three minutes after induction, the patients received TL (4% lidocaine, 4 mL). This was followed by immediate EI. In Group C (n=25), EI was performed two minutes after TL. Heart rate, arterial blood pressure and rate- pressure product (RPP) were measured from one minute before induction until five minutes after EI.

The changes of RPP caused by TL alone in Group C (TL; +34.6 +/- 29.0%, mean +/- SD) were significantly (P <0.01) less than those caused by EI without TL in Group A (+77.3 +/- 42.6%). EI after TL in Group C did not cause significant changes in RPP (+5.4 +/- 15.2%). There were no significant differences between Groups A and B (+58.3 +/- 36.6%).

We conclude that the cardiovascular responses to TL alone are half as great as those to EI without TL, and that TL is effective for attenuation of the cardiovascular responses to EI. EI should be performed more than two minutes after TL.