Díez, J.; García Aldao, U. Spray-As-You-Go Con lidocaína Al 2% Vs. 4% Para intubación Despierto Con Fibro En vía aérea difícil: Xue FS, Liu HP, He N, Et Al. Spray-As-You-Go Airway Topical Anesthesia in Patients With a Difficult Airway: A Randomized Double-Blind Comparison of 2% and 4% Lidocaine. Anesthesia & Analgesia 2009;108:536-43. Rev Elect AnestesiaR 2010, 2, 3.