| This study was to research the influence of hemodilution in patients with different BMI on propofol plasma concentration during the target controlled infusion and to approach the feasibility, safety and superiority of propofol infusion by a closed-loop infusion system guided by BIS.In the first research, selecting thoracic or abdominal surgery patients would undergo general anesthesia of 60 cases, ASA Ⅰ~Ⅱ, divided into Group A(BMI 18.5~24.9) and Group B(BMI>30). 30 patients of each group were randomly divided to there different groups: Group H1(AHHD group), Group H2(ANHD group) and Group NH(control group). After tracheal intubation, all cases accepted intravenous anesthesia maintained by TCI of propofol at 2μg·ml-1. Group H1 was infused with hydoxyethyl starch of 10ml·kg-1. Group H2 was conduted by removing blood from radial artery with 7ml·kg-1 and replacing ti with hydoxyethyl starch 7ml·kg-1. Group NH were infused with ringer’s solution according the physical loss. Radial artery was cannulated for MAP monitoring and blood sampling. Collected the blood samples at the time 30 second and 60 second after TCI of propofol(T1,T2), when the time the patients lost consciousness(T3), the time calculated plasma concentration and effect-site concentration of propofol were 2μg·ml-1(T4), the time before HD(T5) and after HD(T6). The BIS, HR, MAP and calculated plasma concentration(Ccp) at each time point were recorded. Ccp and measured plasma concentration(Cmp) werecompared at each time.In the second research, allocating another 40 patients scheduled for laparoscopic operation randomly to two groups with 20 cases for each: Group C, the closed-loop group was performed using a proportional differential algorithm to TCI of popofol automaticly based on monitoring of bispectral index. Group O, the open target control infusion group was performed manually guided by the bispectral index with manual adminstrtion, In ??manual?? mode, the anesthesiologist needs to change the propofol infusion dose to maintain the BIS as close as possible to a desired target. In both modes, the system records the input variable from the BIS monitor as well as output data at ten-second intervals for subsequent analysis. TCI propfol was induced at a target of 4μg·ml-1, maintained from 2 to 5μg·ml-1. For both groups, bispectral index were maintained from 45 to 55. Remifentanil TCI was infused at a target of 4 ng·ml-1 and was maintained according to the situation. The change in MAP, HR and BIS were recorded before anesthesia(t0), BIS was 50(t1), intubation(t2), skin incision(t3), postoperation 5min(t4), at the time of removing the gallbladder or ovarian cyst(t5) and suturing of the skin(t6).The propofol total doses at t1 and t5 were calculated. Observed and recorded incidence of intraoperative awareness, the nausea and vomiting, the agitation and chills in these patients after operation.In the fist research our results show that:Fist, the measured plasma concentration(Cmp) were compared in the same group: Cmp were no significant differents between Group A-H1, Group A-H2 and Group A-NH at T1 to T5(P>0.05). Cmp of propofol were no significance between Group B-H1, Group B-H2 and Group B-NH at T1 to T5(P>0.05).There were significant differents between Group A-H1, Group A-H2 and Group A-NH at T6(P<0.05).There were significant differents between Group B-H1, Group B-H2 and Group B-NH at T6(P<0.05).Second, the measured plasma concentration(Cmp) were compared in the different group: compared with Group A, Cmp of propofol were higher in Group B at T1 to T4(P<0.05) and were lower in Group B at T6. Cmp of propofol were no significance between Group A-H1 and Group A-H2, Group B-H1 and Group B-H2 at any time(P>0.05).Third, the BIS were compared in the same group: the BIS value were no significant differences at T1 to T5 in any group(P>0.05). Compared with Group A-NH, BIS value were no significant differents between Group A-H1 and A-H2 at T6(P>0.05). Compared with Group B-NH, BIS value were significant lower in Group B-H1 and B-H2 at T6(P<0.05).Fourth: compared with Group A-H1, BIS value were significant lower in Group B-H1 at T6(P<0.05) and the same with Group A-H2 and B-H2.In the second research our results show that:First, compared with Group C, MAP was decreased significantly at t1, t3, t4 and t5 in Group O(P<0.05). HR change a lot at t5 in Group O(P<0.05).Second, compared with Group C, BIS was decreased significantly at t2 to t5.Third, total dose of propofol in the Group C was statistically lower than those in the Group O(P<0.05).Fourth, the postoperative complications were no significant in both group.From results, the following conclusions can be drawn: 1. No matter ANHD or AHHD would reduce the actual propofol plasma concentration at constant infusion with the same level. Effects of HD on plasma concentration of propfol is higher during TCI in obese patients and there are significant differences with BIS. 2. Automated titration guided by BIS for propofol infusion is feasible without increase in haemodynamic adverse effects. Adverse reactions associated with the test system of surgery does not appear, indicating thatCLAN used in the operation is safe. |
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