The Influence Of Age On Hemodynamics And Sedative Effect In Propofol Anesthesia With Target-controlled Infusion

Objective Using the observer's assessment of alertness/sedation scale(OAA/S) and bispectral index(BIS) to assess the sedation depth in propofol anesthesia with targetcontrolled infusion(TCI), this study observed the changes of hemodynamics and sedative effect in different age groups, and the aim was to explore the influence of age on hemodynamics and sedative effect in propofol anesthesia with TCI.Methods One hundred and eighty patients scheduled for elective surgery under general anesthesia were randomly enrolled in this study. All patients were allocated into three groups by age(youth, middle-aged, elderly group). The patients were monitored with electrocardiogram(ECG), heart rate(HR), pulse oxygen saturation(Sp O2), mean artery pressure(MAP) and bispectral index(BIS). And the value before infusion had been recorded as the baseline(OAA/S was 5). Plasma concentration of propofol was set for 4?g/ml. While we began to infuse propofol using TCI pump, we repeatedly assessed the patient OAA/S every 5 seconds. We recorded HR, MAP, BIS, the time spent and the propofol plasma concentration displayed on the TCI pump when the OAA/S firstly reached to 4, 3, 2, 1, and 0 respectively. The time point that patient OAA/S reached to 0 had been recorded as the loss of consciousness(LOC). Then we intravenously injected fentanyl(2?g/kg) and cisatracurium(0.15mg/kg).Endotracheal intubation was executed and the patient received mechanical ventilation. MAP, HR, BIS, the propofol plasma concentration and the time spent were compared in three groups at different time points.Results In all groups, MAP, HR and BIS at LOC were lower than the baseline(P<0.05). At the same OAA/S point, the percentage of fall in MAP in youth group was greater than that in elderly group(P<0.05). When the OAA/S was 4, the HR in the youth and middle-aged group were higher than their baseline(P<0.05), but in the elderly group, there was no significant difference(P>0.05). The propofol plasma concentrations were different among three groups when the OAA/S was 2, 1 and 0 respectively(P<0.05). The plasma concentration of the middle-aged group was lower than that of the youth group but higher than the elderly group. However the differences didn't exist when the OAA/S was 4 and 3 respectively(P>0.05). When the OAA/S was 1 and 0, the time spent in middle-aged group was less than youth group, and the elderly group less than the middle-aged group(P<0.05). When the OAA/S was 2, the elapsed time in elderly group was less than youth group(P<0.05).There were no significant differences among three groups when the OAA/S was 4 and 3 respectively(P>0.05).Conclusion Age is a key factor influencing the hemodynamics and sedative effect in propofol anesthesia with TCI. With the increase of age, the propofol plasma concentration at LOC decreases. The greater the patient age is, the faster the effect of propofol with TCI, which contradict the traditional view.