In Reply:—

I would like to thank Drs. Davis and Cook-Sather for their comments and would like to address some of the issues they have raised. Our study found that the technique of lighted stylet intubation in the presence of cricoid pressure differs sufficiently from the technique in which cricoid pressure is not applied to require a separate learning curve. As the intubator, I was as good with the technique as an experienced lighted stylet intubator would be when faced with an unexpected lighted stylet intubation in which cricoid pressure was being applied. When learning direct laryngoscopy, cricoid pressure is seldom applied purely for teaching purposes when not required clinically. The same may be true for lighted stylet intubation. The fact that a separate learning curve for lightwand intubation in the presence of cricoid pressure is required should be of value to practitioners of lighted stylet intubation because they should now be aware that the technique requires learning and practice for use in an emergency.

The times to successful intubation with and without cricoid pressure were compared in the study and were consistently longer in the cricoid pressure group, even after 30 patients and with the four patients requiring multiple attempts omitted (fig. 1).

Fig. 1. Estimated survival time in lightwand intubation for 60 patients.

Fig. 1. Estimated survival time in lightwand intubation for 60 patients.

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The statement “The lightwand may be useful as an alternative for tracheal intubation during rapid-sequence induction of anesthesia in the presence of a full stomach” was made in the context of a requirement for general anesthesia in the presence of a full stomach and features suggestive of difficult direct laryngoscopy. The results of the study bear out the concerns of Davis and Cook-Sather, with 10% of patients requiring two attempts for successful intubation and a 3% failure rate after three attempts.

Regarding the technique of intubation, lifting force with the nondominant hand was applied (Material and Methods section:“The jaw was then lifted forward with the left hand of the intubating anesthesiologist”). The position of the hand was not described but was gripping the lateral jaw and molars as suggested by Davis and Cook-Sather. My fellow authors thought that the force that could be applied in this way was substantially less than that which can be applied by applying the tip of a Macintosh blade to the vallecula and using the handle of the laryngoscope as a lever. The visual cues for lighted stylet intubation were not hindered by the hand applying cricoid pressure because this involved the tips of the thumb and forefinger only.

The use of the Surch-lite bent to 90° was in accordance with published techniques 1available during preparation for the study. Both Davis and Cook-Sather practice pediatric anesthesia, and the shallower 110° angle may be more appropriate in their patients than the adults in our study. However, a shallower angle and a removable stiffening stylet may prove useful and should be investigated.

Hung OR, Murphy M: Lightwands, lighted stylets and blind techniques of intubation. Anesthesiol Clin North Am 1995; 13: 477–89