The aim of this study was to investigate whether a small dose of midazolam and lessening the propofol dosage could prevent cardiovascular change at tracheal intubation for induction in aged patients.

Eighty patients over 65 years (ASA physical status 1, 2) scheduled for elective surgery received general anesthesia with remifentanil and propofol or midazolam. Patients in group P (n = 40) were induced with 0.9% NaCl 0.03 ml/kg, propofol 1. 2 mg/kg and remifentanil. Patients in group MP (n = 40) were induced with midazolam 0.03 mg/kg, propofol 0.8 mg/kg and remifentanil. The time taken to reach loss of consciousness (LOC) and the value of bispectral index score (BIS) at LOC were recorded. After LOC, 0.8 mg/kg of rocuronium was given and tracheal intubation was performed. The mean blood pressure (MBP) and heart rate (HR) were recorded before induction as the base value, before intubation, immediately post-intubation and 3 minutes after intubation.

Compared with the base values, MBP at before intubation and 3 minutes after intubation was significantly decreased in group P and group MP (P < 0.05). Compared with group P, the decrease of MBP was significantly less at before intubation, immediately after intubation and 3 minutes after intubation in group MP (P < 0.05). The time taken to reach LOC was significantly decreased in group MP compared with that in group P (P < 0.05). There were no significant differences of HR at any time between the two groups.

Co-induction with midazolam and propofol could prevent a marked BP decrease at tracheal intubation for induction in aged patients.