[Hemodynamic responses to orotracheal intubation with upsherscope or Macintosh direct laryngoscope]

To compare the hemodynamic responses to orotracheal intubation via Upsher-scope (USSP) or Macintosh direct laryngoscope (MDLS) under general anesthesia.

Fifty patients with ASA grade I-II and undergoing the elective plastic surgery and requiring orotracheal intubation were randomly allocated to either the USSP (U group) (n=25) or MDLS (M group) (n=25). After standard intravenous anesthetic induction, orotracheal intubation was performed using a USSP or a MDLS. Noninvasive systolic blood pressure (SBP), diastolic blood pressure (DBP), and heart rate (HR) were recorded before and after anesthetic induction, at intubation and every minute thereafter for 5 minutes. The time spent in tracheal intubation was recorded. The mean blood pressure (MBP) and rate-pressure product (RPP) were calculated.

The intubation time was not significantly different between these two groups (P > 0.05). After anesthetic induction, SBP, DBP, MAP, and RPP in these two groups decreased significantly as compared with preinduction values. The orotracheal intubation caused significant increases in SBP, DBP, MAP, and RPP in these two groups in comparision with postinduction values (P < 0.05), but these hemodynamic changes lasted only 1 to 2 minutes and then decreased gradually to the postinduction level. The blood pressure changes caused by orotracheal intubation did not exceed the preinduction values (P > 0.05). As compared to, the maximal HR values in these two groups during observation (from the beginning of intravenous anesthetic induction to 5 min after intubation) were significantly higher than their preinduction values (P < 0.05). The maximal RPP values in M group during observation were significantly higher than their preinduction values (P < 0.05), but no such significant difference was observed in U group (P > 0.05). The hemodynamic data at each time point during the observation had no significant differences between these two groups. (P > 0.05).

Orotracheal intubation using the USSP and MDLS may result in similar hemodynamic responses. The standard general anaesthesia can effectively inhibit the pressor, but not the tachycardiac responses caused by orotracheal intubation via USSP or MDLS. USSP is not superior than MDLS in palliating the adverse cardiovascular stress responses to orotracheal intubation.