Objective: Stress response caused by endotracheal intubation may be harmful for the coronary or cerebral circulation of high-risk patients. This study evaluated the hypothesis that tracheal intubation via an intubating laryngeal mask airway is associated with less cardiovascular and endocrine stress response than the conventional technique using direct laryngoscopy.
Design: Randomized, patient-blinded trial.
Setting: University department (single center).
Participants: Eighty-six patients undergoing elective coronary artery surgery.
Intervention: Tracheal intubation was performed via an intubating laryngeal mask or by conventional direct laryngoscopy after standardized induction of anesthesia.
Measurements and main results: Electrocardiogram with automatic ST-segment analysis and invasive measured blood pressure were recorded continuously and blood samples to analyze norepinephrine plasma levels were taken at 4 times. Catecholamine concentrations and the pressure-rate product were analyzed by using an analysis of variance for repeated measures. In both groups, the pressure-rate product (p = 0.003) and norepinephrine concentrations (p < 0.0001) significantly decreased after induction of anesthesia. However, the fall was more marked in the patients intubated via the laryngeal mask (p = 0.031) than in patients receiving direct laryngoscopy. There were neither signs of cardiac ischemia nor major adverse events during induction of anesthesia.
Conclusions: Reduction of cardiovascular and endocrine stress response associated with endotracheal intubation is more pronounced when performed via the intubating laryngeal mask. Thus, this technique can be helpful in high-risk cardiac patients.