Background & Objectives : Laryngoscopy and tracheal intubation may lead to tachycardia, hypertension and dysrhythmia or myocardial ischemia. In this double blind study, the effects of midazolam and lidocaine on hemodynamic response to endotracheal intubation have been examined.

  Methods : 52 ASA class one patients, aged 20-50, who were candidate for elective inguinal hernia surgery with general anesthesia, were randomly assigned to two groups. All patients received normal saline or Ringer's lactate solution (5ml/kg) about 5-10 minutes before induction of anesthesia and were preoxygenated for 3 minutes. Group 1 received midazolam (0.05 mg/kg) and group 2 received lidocaine (1.5 mg/kg) during 3 minutes prior to intubation. Anesthesia was induced with fentanyl (100 µ g) and thiopental (5 mg/kg) and trachea was intubated by the aid of succinyl choline (1.5 mg/kg). Anesthesia was maintained with halothane (0.5-0.75%) and equal proportions of nitrous oxide and oxygen. Systolic and diastolic blood pressure, mean arterial pressure (MAP) and heart rate were recorded before premedication and intubation, as well as immediately two and five minutes after intubation. The data were analyzed by SPSS software using paired t-test.

  Results : After intubation�Systolic and diastolic blood pressure, MAP and heart rate increased in both groups compared to the baseline values. The difference in increasing diastolic blood pressure and MAP between the two groups was significant (p<0.05), but the difference in increasing systolic blood pressure and heart rate between two groups was not statistically significant. The increase in diastolic blood pressure and MAP in group 1 was significantly more than group 2 (p<0.05).

  Conclusion : Clinically, midazolam was as much effective as lidocaine in controlling response to intubations. Consequently it can be used as an alternative lidocaine in intubations. It has also other priorities such as amnesia, anti-anxiety and anti-agitation.