Comparison of Effects of Different Doses Dexmedetomidine on Inhibiting Tracheal Intubation-Evoked Haemodynamic Response in the Elderly Patients.

Background: Dexmedetomidine (DEX) is a selective α2-adrenergic receptor agonist with anxiolytic and analgesic properties. In the present study, we aimed primarily to assess the effects of DEX on sedation, cognitive function and cardiovascular reflex responses before, during and after the tracheal intubation in the elderly patients.

Materials And Methods: Eighty patients undergoing elective abdominal surgery were randomly assigned to four Groups: Group A(saline, n=20), Group B (0.25μg/kg DEX, n=20), Group C (0.50μg/kg DEX, n=20) and Group D (1.00μg/kg DEX, n=20). With the constant speed infusion of saline and a loading different doses of DEX (diluted with saline to 50ml) for 10min respectively before induction of anaesthesia, the values of arterial pressure {systolic blood pressure (SBP), diastolic blood pressure (DBP)}, heart rate (HR) and bispectral index (BIS) at the time point of before pump DEX (T0), at the end of infusing DEX (T1), before tracheal intubation (T2), at the moment of tracheal intubation (T3) and 5min after trachea intubation (T4) were observed, oxygen saturation (SPO2) and the Modified Observers Assessment of Alertness/Sedation Scale (OAA/S) score were observed at the time of T1 and T0.

Results: Comparison among Groups, compared with Group A, SBP and DBP values in Group C at T2 showed significant differences (p<0.05), SBP and DBP values in Group D at T1, T2 and T4 indicated significant differences (p<0.05), HR values in Group D at T1, T2, T3 and T4 showed significant differences (p<0.05); Compared with Group A, BIS values in Group C at T2 and T3 indicated significant differences (p<0.05), BIS values in Group D at T1, T2, T3 and T4 showed significant differences (p<0.05); Comparison between T3 andT2, means of SBP, DBP and HR in Group A and in Group B showed significant differences (p<0.05); Group D showed significant differences in SPO2 and (OAA/S) betweenT1 and T0 (p<0.05).

Conclusion: Comparison within Groups and between Groups in different doses DEX, the present result showed that 0.5μg/kg DEX had an effective inhibition, without respiratory depression, on tracheal intubation evoked cardiovascular response in the elderly patients.