Dexmedetomidine suppresses the decrease in blood pressure during anesthetic induction and blunts the cardiovascular response to tracheal intubation.

STUDY OBJECTIVE: To evaluate the effect of dexmedetomidine combined with fentanyl on hemodynamics.

DESIGN: Prospective, double-blinded, randomized study.

SETTING: Operating room of a university hospital.

PATIENTS: 30 ASA physical status II and III patients with mild-to-moderate cardiovascular disease.

INTERVENTIONS: Patients were assigned to one of three groups: Group D-F2 [dexmedetomidine, effect-site concentration (ESC) of fentanyl = two ng/mL]; Group F2 (placebo, ESC of fentanyl = two ng/mL), or Group F4 (placebo, ESC of fentanyl = 4 ng/mL).

MEASUREMENTS: Dexmedetomidine (an initial dose of 1.0 microg/kg for 10 min, followed by a continuous infusion of 0.7 microg x kg(-1) x hr(-1)) or placebo saline was administered 15 minutes before anesthetic induction. Anesthesia was induced with propofol and fentanyl using a target-controlled infusion system. Hemodynamic parameters: systolic (SBP) and diastolic blood pressures (DBP), and heart rate (HR) during anesthetic induction were measured and the percent changes were calculated for both induction and intubation.

MAIN RESULTS: After inducing anesthesia, SBP was significantly higher in Group D-F2 (127 +/- 24 mmHg) than Group F2 (90 +/- 20 mmHg) or Group F4 (77 +/- 21 mmHg). The SBP in Groups F2 and F4 reached 160 +/- 31 mmHg and 123 +/- 36 mmHg, respectively, after intubation, but no significant change in SBP was noted in Group D-F2. The percent increase in SBP due to tracheal intubation in Group D-F2 was 3% +/- 4% and was significantly lower than that of Group F2 (70% +/- 34%) or Group F4 (45% +/- 36%).

CONCLUSION: Dexmedetomidine combined with fentanyl during anesthetic induction suppresses the decrease in blood pressure due to anesthetic induction and also blunts the cardiovascular response to tracheal intubation.