Comparative study of hemodynamic responses to orotracheal intubation with intubating laryngeal mask airway.

BACKGROUND: Intubating laryngeal mask airway (ILMA) offers a new approach for orotracheal intubation and is expected to produce less cardiovascular stress responses. However, the available studies provide inconsistent results. The purpose of this study was to identify whether there is a clinically relevant difference in hemodynamic responses to orotracheal intubation by using ILMA and direct laryngoscope (DLS).

METHODS: A total of 53 adult patients, ASA physical status I-II, scheduled for elective plastic surgery under general anesthesia requiring the orotracheal intubation, were randomly allocated to either DLS or ILMA groups. After a standard intravenous anesthesia induction, orotracheal intubation was performed. Noninvasive blood pressure and heart rate were recorded before (baseline values) and after anesthesia induction (post-induction values), at intubation and every minute for the first 5 minutes after intubation. The data were analyzed using Chi-square test, paired and unpaired Student's t test, and repeated-measures analysis of variance as appropriate.

RESULTS: The mean intubation time in the ILMA group was longer than that in the DLS group (P < 0.05). The blood pressure and heart rate increased significantly after intubation in the two groups compared to the post-induction values (P < 0.05), but the maximum value of blood pressure during the observation did not exceed the baseline value, while the maximum value of heart rate was higher than the baseline (P < 0.05). During the observation, there were no significant differences in blood pressure and heart rate among each time point and in the maximum values between the two groups.

CONCLUSIONS: Orotracheal intubations by using ILMA and DLS produce similar hemodynamic response. ILMA has no advantage in attenuating the hemodynamic responses to orotracheal intubation compared with DLS.