Controls should exist for hyperoxic and normoxic conditions in all experiments involving anesthetics.

Anesthesiology 2013; 118:460-71 464 Correspondence advantages and disadvantages. The “spray as you go” technique may be unnerving to the less trained anesthesiologist because it causes coughing and perhaps a subsequent loss of vision when spraying through the fiberscope. Therefore, topical anesthesia may be achieved with the fiberscope but intubation may fail! We chose the transtracheal local anesthetic technique because of this procedure being the preferred method in the centers included in our study and because transtracheal anesthesia produces the least coughing during endoscopy.2 However, mastering different topical anesthesia methods will most certainly prove helpful in handling patients with difficult airways. Finally, we think that Drs. Xue, Cheng, and Li would agree with us in the theoretical concern that video laryngoscopes may cause more pressure on the pharyngeal/laryngeal structures than the fiberscope. In this context, manikin studies have limitations because of the anatomy of manikins not being directly transferrable to patients. Airway manikins upper airway “tissue are stiff, noncompliant and static rather than soft, fragile, and dynamic.”3 For further elucidating this topic, we look forward to see the results of human studies.