A Fluoroscopic Comparison During Intubation with Lighted Stylet,GlideScope,and Macintosh Laryngoscope

Abstract
The question of which is the optimum technique to intubate the trachea in a patient who may have a cervical(C)-spine injury remains unresolved. We compared, using fluoroscopic video, C-spine motion during intubation for Macintosh 3 blade, GlideScope®, and Intubating Lighted Stylet, popularly known as the Lightwand or Trachlight®. Thirty-six healthy patients were randomized to participate in a crossover trial of either Lightwand or GlideScope to Macintosh laryngoscopy, with in-line stabilization. C-spine motion was examined at the Occiput-C1 junction, C1-2 junction, C2-5 motion segment, and C5-thoracic motion segment during manual ventilation via bag-mask, laryngoscopy, and intubation. Time to intubate was also measured. C-spine motion during bag-mask ventilation was 82% less at the four motion segments studied than during Macintosh laryngoscopy (P < 0.001). C-spine motion using the Lightwand was less than during Macintosh laryngoscopy, averaging 57% less at the four motion segments studied (P < 0.03). There was no significant difference in time to intubate between the Lightwand and the Macintosh blade. C-spine motion was
reduced 50% at the C2-5 segment using the GlideScope (P < 0.04) but unchanged at the other segments. Laryngoscopy with GlideScope took 62% longer than with the Macintosh blade (P < 0.01). Thus, the Lightwand (Intubating Lighted Stylet) is associated with reduced C-spine movement during endotracheal intubation compared with the Macintosh laryngoscope.

Endotracheal intubation is frequently required for trauma patients as part of the resuscitative effort (1) or for patients with unstable cervical spine (C-spine) requiring surgery (2). When the status of the C-spine is unknown or when it is known to be unstable, there is potential for spinal cord damage during intubation (1–3). The Macintosh 3 blade is commonly used for direct laryngoscopy;two other methods often used for endotracheal intubation are the Intubating Lighted Stylet or Lightwand (Trachlight®, Laerdal, Armonk, NY) and the GlideScope® (Saturn Biomedical Systems, Burnaby, BC, Canada). These intubating techniques can be performed rapidly and safely and could involve less C-spine movement than direct Macintosh laryngoscopy.

Previous studies have evaluated direct Macintosh laryngoscopy, Bullard laryngoscope, bag-mask ventilation, fiberoptic-guided oral and nasal intubation, esophageal Combitube, Laryngeal Mask Airway, and Intubating Laryngeal Mask Airway with respect to C-spine movement during intubation (3–9). Agro et al. (10) compared quality of laryngeal view using the GlideScope versus the Macintosh blade, with in-line stabilization provided, but C-spine movement was not assessed. There have been no studies examining C-spine movement associated with GlideScope use.

A study of the Lightwand has examined success rates with C-spine precautions (11), but no controlled studies of C-spine movement with use of the Lightwand have been published. Konishi et al. (12) examined C-spine movement in 20 healthy patients tracheally intubated using a lighted stylet. This pilot study lacked control group and used only one static radiograph during Lightwand use, which might not correspond to the maximal C-spine movement.

This prospective, randomized, controlled, crossover trial compared C-spine movement during use of the GlideScope or Lightwand versus direct laryngoscopy with the Macintosh 3 blade. The movement of the C-spine was recorded using fluoroscopic video to determine the maximal angular displacement of the vertebrae. The secondary endpoint was time to accomplish laryngoscopy. The
hypothesis was that endotracheal intubation using the Lightwand or GlideScope would result in reduced C-spine movement compared with direct Macintosh laryngoscopy, as determined by fluoroscopic video.

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