Purposc: Lidocaine diffuses across endotracheal tube cuffs, which may serve as a reservoir for local anesthetic to assist in the prevention of E-l-l--induced cough while emerging from general anesthesia. However, the rate of diffusion is slow. Two techniques, alkalization and warming, may increase the proportion of uncharged drug available for diffusion. The purpose of this study is to determine the effectiveness of warming alkalization or warming with alkalization on diffusion. Methods: Four preparations of lidocaine 4% were studied. Group (Gr) L -lidocaine (24~ Gr WL -warmed lidocaine (38~ Gr AL -alkalized lidocaine (24~ Gr WAL -warmed, alkalized lidocaine (38~ Twenty-four Mallinckrodt 8.0 ID (Mallinckrodt Critical Care Division of Mallinckrodt, Inc., Glens Falls, New York) endotracheal tube cults were filled with 6 ml of one of the four preparations. They were then placed in a 20 ml water bath at 38~ and samples were drawn from the water bath at intervals for up to 360 rain. The lidocaine concentration in each sample was determined by gas chromatography. Results: The highest lidocaine concentration was reached in Gr WAL (410.98 ---8.53/Jg'ml -i) after 300 min and then decreased to 376.18 ___ 4.59/Jg'ml -~ after 360 rain. In Gr AL the highest concentration (235.05 _-_ 2.99 Hg.ml -I) was reached after 360 rain. Lidocaine concentrations in Gr L and WL after 360 min were 3.19 __-I. 16 Hg-ml -I and 4.32 +-2.02/lg'ml -I respectively. Condition: Alkalization with or without warming, but not warming alone, promotes lidocaine diffusion from endotracheal tube cuff.Obje~df : La lidocaine diffuse, lentement toutefois, au travers des ballonnets des tubes endotrach~aux. Les balIonnets peuvent servir de r&ervoir ~ ranesth&ique local et participer ~ la prevention de la toux induite par le TET pendant la r&up&ation de I'anesth~sie g6n&ale. I'alcalinisation et le r&hauffement peuvent accro~tre la proportion de m~dicament susceptible de diffuser. I'objectif de la pr&ente &ude est de d&erminer I'eflicacit~ du r&hauffement, seul ou avec alcalinisation, sur la diffusion. M&hode : On a &udi~ quatre preparations de lidocaine. Le groupe (Gr) L -lidoca'ine (24 ~ Gr LR -lidoca'ine r&hauff& (38 ~ Gr LA -lidoca/ne alcalinis& (24 ~ Gr LRA -lidocaine r&hauff&, alcalinis& (38 ~ Vingtquatre tubes endotrach6aux ~ ballonnets Mallinckrodt de DI 8,0 (Mallinckrodt Critical Care Division of Mallinckrodt, Inc., Glens Falls, New York) ont fitfi remplis de 6 ml de rune des preparations. Plac& ensuite dans un bain d'eau de 20 ml ~ 38 ~ on en a ensuite retir~ des &hantillons ~ des intervalles pouvant aller jusqu'~ 360 min. La concentration de lidoca'ine a ~t~ d6termin6e par chromatographie en phase gazeuse. R&ultats : La plus forte concentration de lidocaine a ~t~ atteinte dans le Gr LRA, 410,98 ---8,53 Hg'ml-', apr~s 300 rain, puis elle a baiss~ ~ 376, 18 ---4,59 ~/g-ml-' apr& 360 rain. Dans le Gr LA, la concentration maximale &ait de 235,05 ___ 2,99/ag.ml-' apt& 360 rain. Dans les Gr Let LR, la lidoca'l'ne ~tait, apr& 360 rain de 3, 19 _ I, 16/ag.ml-...