Detection of perioperative myocardial ischaemia

Sir,—We did not study the Belscope with the prism attached. The instructions with the Belscope state that the prism is only needed three times per 1000 intubations and is not recommended for routine use, as the medium restricts the field of view. The instructions state, and this is borne out by our experience, that where the difficulty of laryngoscopy requires the prism to be used, the tracheal tube will almost always need further curvature, using a J-shaped introducing wire; alternatively, a bougie may be inserted and the tracheal tube "railroaded" over it. This was inappropriate for our study with medical students. Overall it is difficult to comment further on the letter by Gajraj, Chason and Shearer, as there are no details of the patients, grade of laryngoscopy or experience of the intubator(s). They state that time to intubation was longer with the Belscope. Bellhouse [1] has already said that the "Macintosh blade has been found to be marginally quicker to use" than the Belscope and our study showed that although intubation with the Belscope was slower, it still met the criteria for time to intubation laid down by the American Advanced Cardiac Life Support Examination [2]. We cannot comment on cervical spine movement in our study as that was not its purpose: we were using a mannikin not patients.