Study Objective: To compare the stress response following tracheal intubation using direct laryngoscopy to that using fiberaptic bronchoscopy technique. Design: Randomized, prospective study. Patients: 51 ASA physical status I and II patients who were scheduled for an elective surgery with general anesthesia. Interventions: Patients were randomly assigned to receive either direct laryngoscopy or fiberoptic orotracheal intubation, as part of general anesthesia. A uniform protocol of anesthetic medications was used. Measurements: Blood pressure and heart rate were measured before induction, before endotracheal intubation, and 1, 2, 3, and 5 minutes afterwards. Catecholamine (epinephrine and norepinephrine) blood samples were drawn before the induction, and I and 5 minutes after intubation. Main Results: Duration of intubation was shorter in the direct laryngoscopy group (16 9 (16.9 +/- 7.0 sec, range 8 to 40) compared with the fiberoptic intubation group (55.0 +/- 22.5 sec, range 29 to 120), p < 0.0,001. In both groups, blood pressure and heart rate were significantly increased at 1, 2, and 3 minutes after intubation, but there was no significant difference between the two study groups. Catecholamine Levels did not increase after intubation and did not correlate with the hemodynamic changes. Conclusions: The use of either direct laryngoscopy or fiberoptic bronchoscopy produces a comparable stress response to tracheal intubation. Catecholamine Levels do not correlate with the hemodynamic changes. (C) 2003 by Elsevier Science Inc.