Effect of the McGRATH MAC(®) Video Laryngoscope on Hemodynamic Response during Tracheal Intubation: A Retrospective Study

BACKGROUND: Hypertension often occurs after tracheal intubation using a Macintosh laryngoscope and may lead to rare but serious complications. The Macintosh laryngoscope may increase the incidence of hypertension because it requires forced alignment of the oral and pharyngeal axes in order to view the glottis. In contrast, the McGRATH MAC video laryngoscope does not require this manipulation. The objective of this study was to evaluate the incidence of hypertension after tracheal intubation using a McGRATH laryngoscope compared with a Macintosh laryngoscope. METHODS: Data of 360 consecutive patients who underwent general anesthesia with tracheal intubation by Macintosh laryngoscope or McGRATH video laryngoscope were obtained retrospectively. A total of 16 variables including patient characteristics, anesthetic drug used, and intubation techniques were extracted as potential factors affecting the incidence of hypertension after intubation. The incidence of hypertension after tracheal intubation was defined as an increase in systolic blood pressure (SBP) >20% of values immediately before intubation. Propensity scoring with inverse probability weighting was used to calculate the odds ratio for the incidence of hypertension after intubation with a McGRATH video laryngoscope as the primary outcome. The mean difference in SBP change between the two laryngoscopes was also calculated. RESULTS: A McGRATH laryngoscope was used in 68 of 360 patients (18%). The numbers of patients who increase in systolic blood pressure of more than 20% was 189 patients (53%). The odds ratio for the use of a McGRATH laryngoscope was 0.43 (95% confidence interval (CI), 0.19–0.96; P = 0.04). The mean difference in SBP change between the two laryngoscopes was -8.6 mmHg (95% CI, -17.4 to 0.2; P = 0.06). CONCLUSIONS: The use of a McGRATH laryngoscope may reduce the incidence of hypertension after tracheal intubation compared to the Macintosh laryngoscope.