The Effects Of Dexmedetomidine Combined With Propofol On Oxygenation And Haemodynamics In Patients With One-lung Ventilation

Objective:To observe the effects of dexmedetomidine on oxygenation and haemodynamics in patients with one-lung ventilation,to provide certain theoretical basis for clinical application.Methods:Forty patients undergoing elective thoracic operation were randomly divided into the study group(Group C) and control group(Group D),each group of twenty patients. Radial artery puncture under local anesthesia and connected additionally to the Flo Trac/Vigileo system to obtain CO、SV、SVI and CI measurements and monitored SBP、DBP、HR and BIS.Patients in group D with using intravenous infusion method was injected 0.5ug.kg-1 dose of DEX for 10 min before induction of anaesthesia followed by an infusion of 0.5ug.kg-1h-1 until 30 min after one-lung ventilation.Group C,in the same syringe infusion same volume of saline.Maintenance anesthesia consisted of propofol target-controlled infusion and fentanyl intravenous bolus injection.TCI of propofol was administered with the Marsh pharmacokinetic model,keep the BIS value between 40 and 60.In both groups,arterial and venous samples were obtained at four time points:T0,5 min after coming into the operating room;Tl,10 min after TLV;T2,15 min after OLV;and T3,30 min after OLV.The Hb、PaO2、PaCO2、SaO2、PvO2 and SvO2 were recorded,and Qs/Qt values were calculated for each measurement time,and record CO、 SV、SVI and CI.Record T0-T3 four time points of SBP、DBP and HR.At the end of the operation, we wrote down the induction dose of propofol and the total dose of anaesthtics all through the surgery.Results:1.There was a decrease in propofol and fentanyl requirement among the patientsin the study group vs. those in the control group.(Induction dose of propofol,88.31±1.11mgvs69.66±10.06mg;Average effect of propofol concentrationl, 2.84±0.102ug.ml-1vs2.65±0.093ug.ml-1;Total dose of fentany1,0.67 ±0.06mgvs0.51±0.03mg,P< 0.05).SPO2 in group D patients who maintain in the proportion of 100% was obviously higher than that of group C, (13/20 vs 5/20, P< 0.05)。2. PaO2 and Qs/Qt were significantly increased in both groups at T1-T3 time points compared with T0,and those in Group C increased more.There were also differences between groups in oxygenation and shunt values at T2/T3 time point (P<0.05).3.SBP and DBP showed statistical differencesin both groups at T1-T3 time points compared with TO (P<0.05). And those of Group D were significantly lower than Group C at T1-T3 time points.(P<0.05).4.CO, CI, SV and SVI were significantly increased in the Group C at T2-T3 time points compared with T1(P<0.05), but not in the Group D.Conclusion:Dexmedetomidine can better maintain the oxygenation function in patients under one-lung ventilation. Using dexmedetomidine significantly reduced the requirement of propofol and fentanyl throughout the total intravenous anesthesia and achieved more stable hemodynamics in thoracic operations.