Hemodynamic response to tracheal intubation via direct laryngoscopy and intubating laryngeal mask airway (ILMA) in patients undergoing coronary artery bypass graft (CABG)

Abstract

Background: A marked stress response including hypertension, tachycardia, arrhythmias and an increase in intracranial pressure often follows direct laryngoscopy. This response can be harmful specially in patients with underlying cardiac disease. The intubating laryngeal mask airway (ILMA)--a new modified laryngeal mask airway--has been introduced that facilitates tracheal intubation without using laryngoscopy. Oropharyngeal stimulation-proposed as the probable cause of stress response--have been shown to be attenuated in ILMA. We conducted this study to evaluate the stress response following two techniques in patients undergoing coronary artery surgery which are most likely to benefit from decreased hemodynamic changes during intubation.

Methods: In this trial, eighty patients, forty in ILMA group and forty in DL group were involved. To determine hemodynamic response during these manipulations, blood pressure (BP) and heart rate (HR) were recorded before and after anesthetic induction (one minute before and one, two and five minutes after successful intubation via either method).

Results: A significant increase in heart rate and blood pressure was detected in both groups after intubation. Despite existence of noted changes in both groups; quantity of these changes was similar in both groups, however quality of changes was not completely similar.

Conclusion: Finally we could hardly ascertain if intubation with ILMA is a prefered method in patients with high cardiac risk or not. But it seems that ILMA does not have much greater benefit over conventional DL in patients undergoing coronary artery by-pass grafting.