Hemodynamic Responses to Tracheal Intubation with Laryngoscope Versus Lightwand Intubating Device (Trachlight) in Adults with Normal Airway

Unlabelled: Lightwand devices are effective and safe as an aid to tracheal intubation. Theoretically, avoiding direct-vision laryngoscopy could allow for less stimulation by intubation than the conventional laryngoscopic procedure. We designed this prospective randomized study to assess the cardiovascular changes after either lightwand or direct laryngoscopic tracheal intubation in adult patients anesthetized with sevoflurane. Sixty healthy adult patients with normal airways were randomly assigned to one of three groups according to intubating procedure under sevoflurane/nitrous oxide anesthesia (fraction of inspired oxygen = 0.33) (n = 20 each). The lightwand group received tracheal intubation with Trachlight, the laryngoscope-intubation group received tracheal intubation with a direct-vision laryngoscope (Macintosh blade), and the laryngoscopy-alone group received the laryngoscope alone. Heart rate and systolic blood pressure were recorded continuously for 5 min after tracheal intubation or laryngoscopy with enough time to intubate. All procedures were successful on the first attempt. The maximum heart rate and systolic blood pressure values obtained after intubation with Trachlight (114 +/- 20 bpm and 143 +/- 30 mm Hg, respectively) did not differ from those with the Macintosh laryngoscope (114 +/- 20 bpm and 138 +/- 23 mm Hg), but they were significantly larger than those in the laryngoscopy-alone group (94 +/- 19 bpm and 112 +/- 21 mm Hg) (P < 0.05). Direct stimulation of the trachea appears to be a major cause of the hemodynamic changes associated with tracheal intubation.

Implications: The magnitude of hemodynamic changes associated with tracheal intubation with the Trachlight is almost the same as that which occurs with the direct laryngoscope. Hemodynamic changes are likely to occur because of direct tracheal irritation rather than direct stimulation of the larynx.