The Pentax airway scope versus the Macintosh laryngoscope: Comparison of hemodynamic responses and concentrations of plasma norepinephrine to tracheal intubation

BACKGROUND The Pentax Airway Scope (AWS) is a video laryngoscope designed to facilitate tracheal intubation with a high-resolution image. The Pentax AWS has been reported to cause less hemodynamic stress than the Macintosh laryngoscope. The aims of this study are to investigate the differences in hemodynamic responses and norepinephrine concentrations to tracheal intubation between procedures using he Pentax AWS and the Macintosh laryngoscope. METHODS Forty patients (American Society of Anesthesiologists class I-II, age range: 18-60 years) were randomly assigned to be intubated with either the Pentax AWS or the Macintosh laryngoscope while under general anesthesia. Routine monitoring, including invasive arterial blood pressure and bispectral index, were applied. Thiopental (4 mg/kg), fentanyl (1 µg/kg), midazolam (0.05 mg/kg), and rocuronium (0.6 mg/kg) were administered for anesthetic induction. Systolic, diastolic, and mean blood pressures and heart rates were recorded pre-intubation, immediately post-intubation (T0), and over the following 10 minutes at one minute intervals (T1, T2, T3, T4, T5…T10). Patient blood was sampled for norepinephrine concentrations pre-intubation (baseline) and post-intubation (T1). Evidence of sore throat was evaluated 30 min and 24 hr after extubation. Data were transformed to % basal and expressed as mean ± SD. RESULTS The systolic, diastolic, and mean blood pressure, and heart rate at T0 and T4 were significantly different between the two groups. There was no significant difference in plasma norepinephrine between the two groups. The difference in incidence of sore throat was not significant between the two groups. CONCLUSIONS Pentax-AWS for tracheal intubation has greater hemodynamic stability than the Macintosh blade laryngoscope.