Effect of distribution and membrane structure of alkalinized lidocaine across an endotracheal tube cuff

In order to prevent pharyngolaryngeal pain, the cough reflex and discomfort caused by use of an endotra­ cheal tube during general anesthesia or after trache­ otomy, endotracheal tube cuffs are filled with lido­ caine solutions to maintain cuff pressure and provide surface anesthesia. Endotracheal tube cuffs have been reported useful as a drug delivery system. However, cuff rupture may occur and cause intoxica­ tion with the local anesthetic agent and mucosal dam­ age. It has been reported that the rate of diffusion of lidocaine across endotracheal tube cuffs increases when lidocaine solution is warmed or alkalinized with sodium bicarbonate. However, the effect of expo­ sure to lidocaine or alkalinized lidocaine solution on the risk of cuff damage is still unknown. We alkalinized 4% lidocaine hydrochloride solution with sodium bicarbonate solution (Meylon Injection 8.4% ; Otsuka Pharmaceutical, Tokyo, Japan) or di­ basic potassium phosphate (Dipotassium Phosphate Corrective Injection ; Otsuka Pharmaceutical), which are used clinically for the treatment of electrolyte im­ balances. We determined the amount of lidocaine dif­ fused across the endotracheal tube cuff over time to assess the usefulness of lidocaine­filled cuffs as a drug delivery system, and observed the effect of lido­ caine and alkalinized lidocaine solutions on the integ­ Effect of distribution andmembrane structure of alkalinized lidocaine across an endotracheal tube cuff