To the Editor:—

We greatly appreciate and commend the recent study by Smith et al.  1comparing intubation difficulties in cervical spine immobilization with the use of the conventional laryngoscope and the WuScope (Achi Corp., Fremont, CA, and Asahi Optical Co.-Pentax, Tokyo, Japan). 2As the inventors of this relatively new device, we feel obligated to respond to issues raised by Smith et al.  1and to share our understanding and experience regarding this device.

First, although Smith et al.  1demonstrated that the WuScope was easy to use and had an excellent success rate, despite their relative inexperience with the device (10 WuScope intubations vs.  3,000 conventional intubations), we would like to stress that WuScope intubation is very different from conventional methods. We recommend that the practitioner exert a conscientious effort to learn and master this new technique. One should watch the instruction video, read the manual, practice assembly and disassembly, and use the WuScope for routine intubations until he or she is proficient with the device.

Second, as pointed out by Smith et al. , 1the WuScope has a flexible fiberscope portion that is traditionally a high-cost item and requires careful handling and proper assembly and disassembly with the rigid blade portion. The manufacturer now has made the WuScope fiberoptic portion less expensive, more durable, and battery operated. Nevertheless, the practitioners should again be reminded to exert the same degree of care as with any traditional flexible fiberscopes to avoid costly repairs.

Third, the conclusion of the study by Smith et al.  1should not be taken to mean that the overall effectiveness of the conventional laryngoscope and the WuScope are similar in cervical spine immobilization cases. We must remember that Smith et al.  1excluded from the study patients with abnormal or difficult airways. The study of Smith et al.  1showed that applying the “immobility” factor to “normal” patients would result in poor laryngeal visualization (39%) and lead to possible difficult, esophageal, or failed intubations with the conventional laryngoscope. In contrast, WuScope intubation is a “visually guided” procedure, and “one can continuously view the endotracheal tube (ETT) as it advances through the glottic opening into the trachea.”3 

In summary, the WuScope is specifically designed to intubate with the patient in the neutral head position, and its tubular blade and fiberoptic imaging create space and overcome immobility in “difficult airways.”2,3,4 

1.
Smith CE, Pinchak AB, Sidhu TS, Radesic BP, Pinchak AC, Hagen AF: Evaluation of tracheal intubation difficulty in patients with cervical spine immobilization. A nesthesiology 1999; 91:1253–9
2.
Wu TL, Chou HC: A new laryngoscope: The combination intubating device. A nesthesiology 1994; 81:1085–7
3.
Smith CE, Sidhu TS, Lever J, Pinchak AB: The complexity of tracheal intubation using rigid fiberoptic laryngoscopy (WuScope). Anesth Analg 1999; 89:236–9
4.
Sandhu NS, Schaffer S, Capan LM, Turndorf H: Comparison of the WuScope and Macintosh #3 blade in normal and cervical spine stabilized patients (abstract). A nesthesiology 1999; 91:3A