Effects Of Different Doses Of Dexmedetomidine On Cardiovascular Responses And Recovery Responses To Tracheal Extubation

Objective To observe the effects of different doses of dexmedetomidine on cardiovascular responses and the quality of recovery to tracheal extubation and to try to find out the ideal dose of dexmedetomidine. Methods Eighty adult patients (ASA classⅠorⅡ)scheduled for LC surgery under general anesthesia were randomly divided into four groups, Age ranged from 18-60 years.10 minutes before the end of surgery, the patients received 10 ml saline in group A, dexmedetomidine 0.3 ug/kg in group B, dexmedetomidine 0.5 ug/kg in group C, dexmedetomidine 0.7 ug/kg in group D, respectively for 10 min. Anesthesia was induced with intravenous fentanyl 3-4 ug/kg, propofol 1.5-2.0 mg/kg and rocuronium 0.6 mg/kg and was maintained with propofol 4-6 mg-kg-1·-h-1and sevoflunce 2-3%. mean atrial pressure (MAP) and heart rate (HR) were recorded before operation,5 min after administration,1 min before the tracheal extubation, at tracheal extubation and 5 min,10 min,20 min and 30 min after the tracheal extubation; the duration from termination of surgery to full recovery of spontaneously breathing, eye opening response to instruction and tracheal extubation were recorded; postoperative complications like restlessness? chill, cough, nausea, vomiting and low SPO2,etal were followed up 30 min after the tracheal extubation; Finally, RSS,VAS during 30 min after extubation and Side effect of drugs are recorded. Results There were no statistically significant differences in sex, age, body weight and times of surgery among the four groups. MAP and HR were significantly decreased after administration in group B, C and D compared with the baseline value before administration and group A (P<0.05).1 min before the tracheal extubation, at tracheal extubation and 1 min after the tracheal extubation, MAP and HR In group A and MAP in group B have increased significantly compared with the baseline value before operation, but that have not increased significantly in group C and group D. At 10 min, 20 min and 30 min after the tracheal extubation, MAP and HR in group C and group D have decreased significantly compared with the baseline value (P＜0.05); The time of breathing recovery, eye opening, and extubation were longer in group D compared with group A, B and C (P＜0.05), and that had no significant difference in group A, B and C;The incidence of postoperative restlessness and cough was lower in group C and D than that in group A (P<0.05); Ramsay sedation score in group B, C and D was higher than that in group A (P<0.05). VAS pain score and the conscumption of fentanyl in group C and D was lower significantly than that in group A (P＜0.05), and that was no signifieantly differences in group C and group D (P>0.05); The incidence of hypotension and bradycardia was higher in group D than other three groups. Pule oxygen saturation and respiratory frequency were no statistieally significant in the four groups. Conclusions Dexmedetomidine 0.5 ug/kg administered 10 min before the end of surgery may attenuate cardiovascular responses to tracheal extubation with fewer side effects of drugs and without longing recovery time, bing an ideal dose to tracheal extubation and providing perfect quality of recovery.