Effects of preanesthetic dexmedetomidine on hemodynamic responses to endotracheal intubation in elderly patients undergoing treatment for hypertension: a randomized, double-blinded trial

Abstract

Background: Dexmedetomidine is an alpha-2 adrenergic agonist with sedative, anxiolytic, and analgesic properties. This study was designed to evaluate the inhibitory effects of preoperative administration of 0.5 µg/kg dexmedetomidine on hemodynamic responses caused by endotracheal intubation in elderly patients undergoing treatment for hypertension.

Methods: Forty elderly (≥ 65 years old) patients who had been receiving hypertension treatment, had American Society of Anesthesiologists physical status II, and were scheduled to undergo elective noncardiac surgery were randomly selected and assigned to 2 groups. Group C received normal saline and group D received 0.5 µg/kg dexmedetomidine intravenously over 10 min just before endotracheal intubation. Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded preoperatively in the ward, immediately after study drug administration, and at 1, 3, and 5 min after endotracheal intubation.

Results: Compared to group C, group D showed significantly lower SBP and MAP at 1, 3, and 5 min as well as significantly lower DBP and HR at 3 and 5 min after endotracheal intubation.

Conclusions: In elderly patients receiving hypertension treatment, a single preanesthetic dose of dexmedetomidine (0.5 µg/kg) effectively suppressed the hemodynamic responses to endotracheal intubation.

Keywords: Dexmedetomidine; Hemodynamics; Intubation; Preanesthetic medication.

Fig. 1. Flow chart of the study. Forty-four patients were recruited, and 2 obese patients (body mass index > 35 kg/m²) were excluded. Randomization was done on 42 patients, with 20 in the control group and 22 in the dexmedetomidine group. Intervention was discontinued in 2 patients in the dexmedetomidine group because the intubation attempt lasted more than 20 s.

Fig. 2. Changes in systolic blood pressure (SBP) in the 2 groups. Group C: normal saline, Group D: dexmedetomidine. ^*P < 0.05 indicates a significant increase in each group, compared to the baseline values. ^†P < 0.05 indicates a significant decrease noted in Group D, compared to the baseline values. ^‡P < 0.05 indicates a significant difference between the groups.

Fig. 3. Changes in diastolic blood pressure (DBP) in the 2 groups. Group C: normal saline, Group D: dexmedetomidine. ^*P < 0.05 indicates a significant increase in each group, compared to the baseline values. ^†P < 0.05 indicates a significant decrease noted in Group D, compared to the baseline values. ^‡P < 0.05 indicates a significant difference between the groups.

Fig. 4. Changes in mean arterial pressure (MAP) in the 2 groups. Group C: normal saline, Group D: dexmedetomidine. ^*P < 0.05 indicates a significant increase in each group, compared to the baseline values. ^†P < 0.05 indicates a significant decrease noted in Group D, compared to the baseline values. ^‡P < 0.05 indicates a significant difference between the groups.

Fig. 5. Changes in heart rate (HR) in the 2 groups. Group C: normal saline, Group D: dexmedetomidine. ^*P < 0.05 indicates a significant increase in each group, compared to the baseline values. ^†P < 0.05 indicates a significant decrease noted in Group D, compared to the baseline values. ^‡P < 0.05 indicates a significant difference between the groups.