Alkalinization of Intracuff Lidocaine Improves Endotracheal Tube-Induced Emergence Phenomena

Abstract

Use of 40 mg of alkalinized lidocaine, rather than lidocaine or air, to fill the endotracheal tube cuff reduces the incidence of sore throat in the postoperative period. This approach also decreases hemodynamic effects, restlessness, dysphonia, and hoarseness.

Endotracheal tube cuff lidocaine is not superior to intravenous lidocaine in short pediatric surgeries

“…Considering the lack of similar studies in pediatric surgeries, the present study warrants further investigation of possible ways to provide smooth emergence from anesthesia in this group of patients. Warming and alkalization are two methods for increasing the diffusion rate of lidocaine and have been reported to further increase the beneficial effects of the drug [2,5,[12][13][14]. It would be interesting to try either or both of these methods in a population similar to ours and see whether they enhance the efficiency of intra-cuff lidocaine.…”

Alkalinization of Intracuff Lidocaine: Efficacy and Safety

“…It has been reported that L-HCl injected alone had a slow diffusion rate across the ETT cuff (1% of release during the 6-hour period) (11). For a clinical effect, large doses of L-HCl (200 to 500 mg) were believed to be required (5)(6)(7)(8)(9).…”

“…The use of alkalinized local anesthetics into the ETT cuff offers the advantages of minimal stress response to smooth tracheal extubation and cough-free emergence. We previously reported that alkalinization of L-HCl allowed the diffusion of 65% of the neutral base form of L-HCl through the hydrophobic structure of the PVC cuff within a 6-hour period and showed that the use of a small dose (40 mg) of alkalinized L-HCl markedly improved ETT tolerance during the first postoperative day (11,12). It appears that only the hydrophobic neutral form of L-HCl was able to diffuse across a membrane, while for charged alkalinized L-HCl only a permeation phenomenon occurred.…”

“…We postulated that if the alkalinized L-HCl had only a volume effect avoiding the overinflation phenomena, no effect could be recorded if ventilation was controlled without N 2 O (null hypothesis) and the results would be equivalent to the air group data. We estimated that using alkalinized L-HCl would decrease the rate of sore throat by 25%-30% as evaluated by VAS compared with the air group (alternative hypothesis) (11,12). Based on these estimates, we calculated a sample size that would permit a type I error of ␣ ϭ 5% with a type II error of ␤ ϭ 5% and power of 95%.…”

“…Hence, large L-HCl doses (200 to 500 mg) have been used (7), which may be dangerous if the cuff ruptures as a result of L-HCl vascular absorption. The addition of 8.4% of sodium bicarbonate (NaHCO 3 ) (i.e., alkalinization) to small doses of L-HCl (40 mg) increased diffusion of L-HCl through the ETT cuff (11,12). However, the clinical relevance of alkalinized L-HCl was never evaluated during anesthesia without N 2 O.…”