This prospective study was designed to compare the cardiovascular response to endotracheal insertion of either an orotracheal tube or a nasotracheal tube.

120 ASA physical status I and II surgical patients requiring general anesthesia and tracheal intubation were studied and assigned to two groups: orotracheal intubation group (n = 60) and nasotracheal intubation group (n = 60). Patients were premedicated with midazolam 0.05 mg/kg and glycopyrrolate 0.005 mg/kg intramuscularly and anesthesia was induced with thiopental sodium 5 mg/kg and succinylcholine 0.1 mg/kg intravenously. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and heart rate (HR) were assessed noninvasively before induction of anesthesia and immediately after intubation, 1 min, 2 min, 3 min, and 5 min after intubation.

Cardiovascular responses such as SBP, DBP, MAP and HR were similar for both techniques and no significant differences between two groups were observed until 5 min after intubation.

In healthy ASA I and II patients with normal blood pressure, induction doses of thiopental sodium 5 mg/kg and succinylcholine 0.1 mg/kg didn't attenuated the cardiovascular response to laryngoscopy and tracheal intubation. Insertion of an endotracheal tube may be the most invasive stimulus during intubation procedures.