Effects Of Dexmedetomidine On Hemodynamics And Requirements Of The Drug During General Anesthesia With Endotracheal Intubation

Objective:To observe the effects of dexmedetomidine with different dosage regimen on hemodynamics and requireents of remifentanil and propofol and the influence to postoperative sedation and adverse reactions during intravenous general anesthesia in patients.Methods:Sixty patients underwent gynecological laparoscopic surgery in intrav- enous general anesthesia were randomly divided into 3 groups: control group(Group P, normal saline),single infusion of dexmedetomidine group(Group D, intravenous dexmedetomidine0.5μg/kg) and continuous infusion of dexemdetomidine group(Group C, intravenous dexmedetomidine 0.5μg/kg and then constant infusion at 0.15μg /(kg·h)). Each group had20 cases. The SBP, DBP and HR were monitored and recorded in the following times:before injection(T0), before anesthetic induction(T1), before intubation(T2), instant after intubation(T3), 3min after intubation(T4), after pneumoperitoneum(T5), drug withdrawal immediately after surgery(T6), instant after extubation(T7) and 3min after extubation(T8).The requirements of remifentanil and propofol were recorded respectively during the surgery. The Ramsay sedation scores in 30 min after surgery, the cases about severe bradycardia, nausea vomiting and other adverse reactions were recorded.Results:Compared with the time point T0, SBP in group P significantly increased at the time points T3, T5 and T7(P<0.05), as well as DBP and HR at the time point T7(P<0.05), and HR significantly decreased at the time points T2,T4 ~T6(P<0.05). Compared with the time point T0, HR in group D significantly decreased at the time points T2~T6(P<0.05).Compared with the time point T0, HR in group C significantly decreased at the time points T1~T6(P<0.05). Compared with group P, SBP in group C significantly decreased at the time points T3, T5 and T7(P<0.05), as well as DBP at the time points T5 and T7(P<0.05).Also, SBP in group D was lower than which in group P at the time points T3 and T5(P<0.05). HR in group C and D significantly decreased compared with group P from the time points T1 to T7(P<0.05). Compared with group P, the requirement of remifentanil in group C decreased 16.99%(P<0.01), and in group D decreased 10.46%(P>0.05), the requirement of propofol in group C and D decreased 5.79% and 7.44%respectively(P>0.05). The Ramsay scores among the three groups have no statistical significance(P>0.05),but the sedation condition in the group C is much better than which in group D and P. The incidence of severe bradycardia and nausea vomiting have no statistical significance(P>0.05), but the cases of severe bradycardia in group C and D are more than which in group P, and the cases of nausea and vomiting is fewer in group C and D.Conclusions:Dexemdetomidine used as adjuvant drugs can effectively reduce the hemodynamic fluctuations in endotracheal intubation and pneumoperitoneum either by single infusion or by continuous infusion with low dose during general anesthesia in laparoscopic operation.,and the latter effects can last until after extubation. Both can decrease the requirements of propofol and remifentanil, but continuous infusion of dexemdetomidine can effectively decrease the requirement of remifentanil. Dexmedetomidine can improve the postoperative sedation and reduce postoperative nausea and vomiting response, but the incidence of severe cardiovascular adverse reactions such as hypotension and bradycardia has increased,need to strengthen monitoring when use it.