We readwith great interest the recent article of Dr. Rai et al.[1] comparingthe flexometallic tracheal tube with the intubating laryngeal mask (ILMA) tube,for nasotracheal fibreoptic intubation. The authors conclude that the incidenceof tracheal tube impingement during nasotracheal fibreoptic intubation issignificantly lower with the ILMA tube than with the flexometallic trachealtube. We believe it would be more appropriate to conclude that the ILMA tube issuperior only when the flexometallic tracheal tube is not appropriatelyoreintated. Dr Rai et al. [1] reported that once the flexometallictracheal tube was rotated anticlockwise by 90°, its success rate improved in 29out of 30 patients. This was essentially the same as the success rate (30 outof 30 patients) of the ILMA. It may be more appropriate to always start withthe flexometallic tracheal tube orientated in a 90° anticlockwise direction. This technique has been used previously during awake fibreoptic orotrachealintubation, and has resulted in a higher success rate of intubation at thefirst attempt (100%) compared to the conventional approach (60%) [2].

Rotation of the bevelled tracheal tube randomly may reducethe difficulty in advancing a tracheal tube over a fibrescope, but 90°anticlockwise rotation should be effective in reducing impingement of thetracheal tube [3]. This manoeuvre was first suggested by Schwartz etal [4] in 1989. Several studies have confirmed that 90° anticlockwiserotation of the tracheal tube significantly decreases the difficulty inadvancing a tracheal tube over a fibrescope [4-7]. Maktabi et al [8] recommend 90° anticlockwise rotation as the first step to overcome theproblem in advancing the tracheal tube. Ho et al. [9] and Wheeler et al [10]also suggest that the first attempt at railroading the tracheal tube should bedone with the tracheal tube already turned in a 90° anticlockwisedirection. In our practice, the simple technique of rotating the bevelledtracheal tube, anticlockwise by 90°, during the first attempt, has become aroutine part of fibreoptic intubation [11].The study by Rai et al [1] shouldhelp popularise this.

In the abstract, the authors conclude that compared to theILMA tube, the incidence of laryngeal trauma from nasotracheal fibreoptic intubationmay be significantly greater with the flexometallic tracheal tube, due to thehigher incidence of glottic impingement. However,we find no evidence to supportthis conclusion in their results. We feel thisis concerning, as inour experience, many readers do not read beyond the abstract of an article, andso some readers may be inadvertently misled by this statement. It would havebeen perhaps more informative to compare the two tubes in terms of the severityof epistaxis, nasal pain, sore throat and dysphonia observed on the firstpost-operative day.

This study was performed in patientswho had elective dental or maxillofacial surgery for which nasotrachealintubation was indicated. Both the flexometallic tracheal tube and ILMA tube lacka Rae contour design. For this reason, we feel that these tubes are not suitablechoices for nasotracheal intubation for oral cavity and jaw surgery, as surgicalaccess may be limited due to vertical protrusion of the tracheal tube from thenostrils. Also, the absence of the distal curve of the tube does not allow thebreathing system tobe positioned away from the surgical field without the useof an additional connector [11]. The ILMA tube also requires a higher cuffpressure [12], which makes its use less desirable, particularly in patientsrequiring nasotracheal intubation for longer periods of time.

F. S. Xue, J. H. Liu, X. Liao,Y.M.Zhang

Plastic Surgery Hospital, Chinese Academy of Medical Sciencesand Peking Union MedicalCollege, Beijing, People’s Republic         of China 100144. E-mail:Fruitxue@yahoo.com.cn.

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2  Sharma D, Bithal PK, Rath GP,Pandia MP. Effect oforientation of a standard polyvinyl chloride tracheal tube on success ratesduring awake flexible fibreoptic intubation. Anaesthesia2006; 61:845-8.

3  Asai T, Shingu K. Difficulty inadvancing a trachealtube over a fibreoptic bronchoscope: incidence, causes and solutions. BritishJournal of Anaesthesia 2004; 92: 870-81.

4  Schwartz D, Johnson C, RobertsJ. A maneuver tofacilitate flexible fiberoptic intubation. Anesthesiology1989; 71:470-1.

5  Hughes S, Smith JE.Nasotracheal tube placement overthe fibreoptic laryngoscope. Anaesthesia1996; 51: 1026-8.

6  Jones HE, Pearce AC, Moore P. Fibreoptic intubation.Influence of tracheal tube tip design. Anaesthesia1993; 48: 672-4.

7  Koga K, Asai T, Latto IP,Vaughan RS. Effect of sizeof a tracheal tube and the efficacy of the use of the laryngeal mask forfibrescope-aided tracheal intubation. Anaesthesia 1997;52:131-5.

8  Maktabi MA, Hoffman H, Funk G,From RP. Laryngealtrauma during awake fiberoptic intubation. Anesthesia andAnalgesia 2002;95: 1112-4.

9  Ho AM, Chung DC, Karmakar MK.Is the Parker Flex-Tiptube really superior to the standard tube for fiberoptic orotracheal intubation?Anesthesiology 2003; 99:1236.

10 Wheeler M, Dsida RM. Fiberoptic intubation:troubles with the "Tube"?. Anesthesiology 2003;99:1236-7.

11 Xue FS, LiCW,Sun HT, Liu KP, Zhang GH, Xu YC, Liu Y, Yu L. Thecirculatory responses to fibreoptic intubation： a comparison of oral and nasal routes.Anaesthesia 2006;61:639-45.

12  Dorsch JA, Dorsch SE.Understanding anesthesiaequipment, construction, care and complications. 4thed. Baltimore: Williams& Wilkins, 1999:563-564.

13 BrainAI, Verghese C, Addy EV, Kapila A. The intubatinglaryngeal mask. I: Development of a new device for intubation of the trachea.British Journal of Anaesthesia 1997; 79:699-70