To the Editor:—
We would like to comment on the recently published study that investigated tracheal intubation using a Surch-lite (Aaron Medical, St. Petersburg, FL) lighted stylet in the presence of cricoid pressure (CP). 1
The authors explored an interesting question: Does CP help or hinder lighted stylet intubation? The trial benefited from a well-defined protocol, comparable subject groups, standard technique, and, most importantly, a single intubator experienced in lighted stylet intubation. However, an important confounding factor was the intubator’s relative inexperience using the lighted stylet in the presence of CP. Was he as good as he could be with this variation in technique? Ideally, Dr. Hodgson would have conducted the study after gaining experience and proficiency using the lighted stylet in this newer setting. Alternatively, he might have presented additional data and included a plot of serial intubation times with regular lighted stylet intubation versus those performed with CP. The authors allude to the problem in their discussion:“. . . all four patients requiring two or more attempts for successful intubation with application of CP were among the first 15 patients to be enrolled in the study.”
Of most concern is the authors’ opening 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.” We feel strongly that its use should not be advocated as a first choice or “alternative” intubation technique in this setting. Lighted stylet intubation is a blind technique that does not confer the same safety that visual assurance of tracheal intubation does in an emergency. However, it may facilitate rapid intubation when conventional techniques are impossible or have failed. Therefore, learning lighted stylet intubation with CP may be valuable.
In their discussion, the authors ponder reasons for the prolonged intubation times with CP. As we mentioned earlier, it may be secondary to difference in the intubator’s experience with the two techniques. The authors propose a more mechanical explanation: that there is an unopposed force from CP in lightwand intubation that is normally opposed by the laryngoscope blade in conventional approaches. This may be so with the technique used by Dr. Hodgson, but in other lighted stylet intubation techniques, 2lifting force can be applied to the upper airway by lifting the mandible forward with the nondominant hand gripping the lateral jaw and molars, thereby elevating the epiglottis. Could this have made a difference in their findings? Finally, the authors did not comment on whether the hand applying CP obscured visual cues, and this could explain some delay in the CP group.
The investigators developed a technique using a Surch-lite bent to 90° with the head and neck in the “sniffing” position. In our experience, a more neutral head and neck position with the lightwand bent to a slightly obtuse (110°) angle gives more straightforward access to the larynx and easier “pushing off” of the tracheal tube. Where the internal stiffener can be withdrawn before “pushing off” (such as in the Trachlight [Laerdal, Armonk, NY]), the more acute hockey-stick formation can be easily accommodated. Undoubtedly, individual experience and preferences are important determinants of successful lightwand intubation, but we wonder whether a repeat of the study with less acute angles or a Trachlight would improve intubating conditions in the presence of CP.