The Effect Of Intravenous Injection Of Lidocaine On Anesthesia Induction Of Propofol

Objective: To determine the safe dose of plasma concentration of lidocaine with singleintravenous injection for providing reference for clinical medication.Methods:40cases of patients undergoing elective thoracotomy and craniotomy operationunder general anesthesia were randomly selected for the study. With the patients enteringthe operating room, basic vital signs were routine monitored. Open venous line and injectmidazolam0.04mg/kg, sufentanil0.3μg/kg, propofol2mg/kg, rocuronium0.6mg/kg.Thencarry out endotracheal intubation, radial artery Allens test which result was negative, andpuncture arterial catheter for the measurement of arterial pressure,anesthesia wasmaintained with propofol6mg/kg h-1and remifentanil0.1μg/kg min-1. All of thepatients were randomly divided into four groups (n=10): be given intravenous injection oflidocaine1mg/kg (group L1.0),1.5mg/kg (group L1.5),2mg/kg (group L2.0) and2.5mg/kg (group L2.5) for30seconds respectively. Then draw3ml of arterial blood fromthe opposite side of radial artery at1min(T1)、2min(T2)、3min(T3) and5min(T5) after theinjection and put them in test tubes containing heparin.Recorded patients’HR、MAP beforeand after intravenous injection of lidocaine Blood samples were centrifuged, processed anddeterminate, plasma concentration of lidocaine in each group was recorded.Results:There was significant difference in the age among four groups of patients (P＜ 0.05). No statistical significant difference was noted in HR and MAP before and afterintravenous injection of lidocaine (P＞0.05). In group L2.5,2cases of patients’ HRdeclined obviously, no abnormal ECG, no danger in operationand and dischargednormally after operation. The plasma concentrations of lidocaine at T1was highest,andthat mean value in group L2.0and group L2.5was more than5000ng/ml.Conclusion:The blood concentrations of single dose injection of lidocaine1-1.5mg/kg areall below the safety limit which is5000ng/ml. Intravenous administration of lidocaine2.0mg/kg is potentially at risk. We do not recommend single intravenous injection oflidocaine2.5mg/kg. Objective:To determine the effects of intravenous lidocaine on the minimum dose ofpropofol for induction.Methods:80cases of patients (ASA I～II,18～70years) undergoing elective colonoscopyunder general anesthesia were randomly allocated into4groups (n=20in each group):begiven intravenous lidocaine1mg/kg(group L1.0),1.5mg/kg(group L1.5),2mg/kg(groupL2.0), normal saline(control group) for30seconds. Immediately give intravenous injectionof propofol10mg/15s until modified observer’s assessment of alert/sedation（MOAA/S）score of1to0points. Recorded HR, MAP, SpO2, the total amount of propofol, time ofanesthesia induction and untoward effects of four groups of patients before intravenouslidocaine and after anesthesia induction.Results:There was significant decreasing in HR after anesthesia induction compared withbefore induction in group L1.0and L2.0(P<0.05). and MAP in all groups were alsoreduced significantly after the induction (P<0.01). The minimum induction dose ofpropofol required in group L1.5and group L2.0were significantly reduced compared withthe control group (P<0.05). In group C:1.5±0.3mg/kg，in group L1.0:1.4±0.3mg/kg，ingroup L1.5:1.3±0.3mg/kg，in group L2.0:1.1±0.3mg/kg, there were significant differencebetween groups (P<0.001).The induction time for group L1.5and L2.0were lesser than the control group (P<0.05). In group C:132.7±20.2s，in group L1.0:132.0±29.0s，in groupL1.5:115.5±20.1s，in group L2.0:99.0±26.4s,there were significant difference betweengroups（P＜0.001)，Spearman correlation coefficient analysis showed a negative linearcorrelation between different doses of intravenous lidocaine and minimum induction doseof propofol (r=-0.600, P<0.001), be the same as with the induction time. There wasstatistically significant difference between groups in injection pain,hypotension,the numberof occurrence of beckoning bradycardia of all of the patients(P＜0.05).Conclusion: Intravenous lidocaine1.5mg/kg and2mg/kg can effectively strengthen thesedative and hypnotic effects of propofol, which set up a dose-response relationship;Lidocaine can not improve fluctuation of hemodynamics before and after anesthesiainduction; Intravenous lidocaine can reduce the incidence of adverse reaction of propofol.