Effects Of Anesthesia And CO₂ Pneumoperitoneum On Cerebral Blood Flow Perfusion

ObjectiveIn order to provide reference for anesthesia and ventilation settings of laparoscopic surgery, and to prevent the neurological complications, we observed and compared the effects of sevoflurane inhalation anesthesia or propofol intravenous anesthesia on cerebral blood flow perfusion in patients undergoing CO2 pneumoperitoneum laparoscopic surgery or open surgery. We also observed the effects of different PETCO2 level on cerebral blood level flow perfusion in the condition of different anesthesia.Methods1 The research contents.1.1 Inhalation and intravenous anesthesia on cerebral blood flow perfusion.Twenty patients undergoing radical mastectomy of Breast Cancer were randomly divided into two groups:the propofol group (n=10) and the sevoflurane group(n=10). Anaesthesia was induced with propofol or sevoflurane combined with fentanyl, and maintained with propofol or sevoflurane combined with remifentanil, respectively. The mean blood pressure (MBP)and heart rate (HR) were monitored by Mindray Patient Monitor. Cerebral blood flow velocity (CBFV, including Vs, Vm, Vd), pulsatility index(PI) and resistance index(RI) were monitored by Elica Transcranial Doppler ultrasonography simultaneously. Those indexes were recorded and analyzed at 7 different time points:before induction(TO), after the loss of consciousness(Tl), after Bolus of fentanyl(T2), after intubation(T3),before surgery(T4), intraoperative 30 min (T5), intraoperative 60min (T6), the end of surgery (T7). Finally analysis the data.1.2 Effect of different anesthetics and PETCO2 level CO2 pneumoperitoneum on cerebral blood flow perfusion.Forty patients undergoing gynecologic laparoscopic surgery were randomly divided into two groups:the propofol group(n=20) and the sevoflurane group(n=20). Anaesthesia was induced with propofol or sevoflurane combined with fentanyl, and maintained with propofol or sevoflurane combined with remifentanil, respectively. MBP, HR, PETCO2, Vs, Vm, Vd, PI and RI were recorded and analyzed at time points of before induction (TO),15min after PETCO2 50mmHg(T1),15 min after PETCO2 35mmHg(T2),15min after PETCO2 25mmHg (T3), the end of surgery(T4)respectively. Finally analysis the data.1.3 Effect of laparoscopic and open rectal cancer resection on cerebral blood flow perfusion.Forty patients according to the type of surgery were divided into two groups:laparoscopy group(n=20) and open group (n=20). Anaesthesia was induced with target-controlled infusion (TCI) of propofol and fentanyl, maintained with propofol combined with remifentanil. At the following time points:before induction(TO),5 min after intubation(T1), incision/the instant after abdominal CO2 insufflation (T2),30 min after incision/abdominal C02 insufflation (T3),60 min after incision/abdominal CO2 insufflation (T4),90 min after incision/abdominal CO2 insufflation(T5),120 min after incision/abdominal CO2 insuff lation (T6),15min before the end of surgery/15min after abdominal CO2 deflation (T7), and the end of surgery (T8), MBP, HR, PETC02, Vs, Vm, Vd, PI and RI were monitored and marked. The operating time and the dosages of anesthetics of two groups were recorded respectively.2 Statistical methodStatistical package SPSS18.0 was used to do the statistical analyses. All quantitative data were expressed as mean±standard deviation (SD) (x±s), The categorica data of the patients'general data were analyzed by chi-square test and the quantitative data of that were analyzed by independent t-test. One-way ANOVA was used to compare the dadta of different time points in the same group. The independent t-test was used to compare a test between groups. Values of P<0.05 were considered as statistically significant.Result1 Inhalation and intravenous anesthesia on cerebral blood flow perfusion.HR and MBP were lower than those before anesthesia during induction and maintenance of anesthesia, HR was no statistical difference between two groups(P>0.05). HR in two groups at T2, T4-T7 was significantly lower than that in the control(T0). The change of RI was similar in the two groups:RI was at a level similar to that at TO in the process. There was no significant difference between PI in two groups in the process, but that of sevoflurane group at T3, T5～T7 time points was significant lower than that at T0. Vm, Vs and Vd of sevoflurane group kept in a level higher than TO, which was different from that of propofol group, however that of propofol from T1 were much lower than that at T0 (P<0.05～0.01). At T3～T7, Vm, Vs of the sevoflurane group was significantly higher than that in the propofol group (P<0.05～0.01), and Vd of the sevoflurane group was also higher than that of propofol group (P<0.05).2 Effect of different anesthetics and PETCO2 level CO2 pneumoperitoneum on cerebral blood flow perfusion.HR, MBP and the index of cerebral blood perfusion was similar in two groups at TO, and no significant difference. Whether with PETCO2 50mmHg-Hypercapnia or PETCO2 25mmHg-hypocarbia, in the process, HR and MBP in two groups were much lower than that at T0(P<0.05-0.01). In addition, at all time points, there was no significant difference between two groups(P>0.05). PI and RI in two groups decreased to much lower than that at T0 (P<0.01). When PETCO2 returned to normal level (35mmHg), PI and RI were back to the TO level. PI and RI increased significantly (P<0.05～0.01), especially PI in the propofol group, significantly higher than the sevoflurane group (P<0.05), when PETCO2 decreased to 25mmHg. Whether in the sevoflurane group or the propofol group, Vm, Vs, Vd increased in hypercapnia(P<0.01), and decreased significantly in hypocapnia(P<0.01), the decrease in the propofol group is more obvious than the other one, and the differences are very apparent. As PETCO2 was back to 35mmHg the normal level, Vm and Vd in the sevoflurane group retured to the TO level, but those in the propofol group decreased significantly to the level lower than TO, and was lower than those in the sevoflurane group(P<0.01). Even at T4-the end of surgery, Vm, Vs and Vd in the propofol group were much lower than those at T0(P<0.05～0.01), yet those in the sevoflurane group recovered to the TO level (P>0.05).3 Effect of laparoscopic and open radical operation on rectal cancer on on cerebral blood flow perfusion. At T0, HR, MBP and the index of cerebral blood perfusion was similar in two groups. HR and MBP decreased slightly. Vm, Vs and Vd also went down(P< 0.05～0.01), while the changes of PI and RI were not notable. At T3-T7, HR and MBP were a little lower than those at T0, while there was no significant difference between HR and MBP of two groups. In the same process, Vm, Vs and Vd in the open group decreased in varying degree to significantly lower than those at T0(P<0.01), with the increase of PI and RI(P<0.05). Meanwhile Vm, Vs, Vd in the laparoscopy group had no significant decrease, nearly no significant difference from those at T0. PI and RI in the laparoscopy group were slightly lower than those at T0(P<0.05～0.01). In the process Vm, Vs, Vd, PI and RI had significant differences between two groups (P<0.05～0.01). Till the and of surgery(T8), Vd and PI in the open group didn't recovered to the TO level yet.Conclusion1 Under the condition of the same anesthetic depth, propofol anesthesia decreased CBF, significantly, but had no significant effect on cerebrovascular tension. Sevoflurane anesthesia was able to maintain CBF stablity, but slightly decreased the cerebrovascular tension.2 Neither propofol nor sevoflurane could impair the decrease of cerebrovascular tension and the increase of CBF induced by hypercapnia. Similarly, neither of these anesthetics could avoid the increase of cerebrovascular tension and the decrease of CBF induced by hypocapnia. But sevoflurane had much less effect on the increase of cerebrovascular tension and the decrease of CBF induced by hypocapnia.3 In process of open colorectal cancer resection, CVR increasd, and CBF decreased significantly. But in process of laparoscopic colorectal cancer resection, cerebrovascular tension and CBF could be maintained.4 The above mentioned changes of cerebrovascular tension and CBF may be related to the effects of propofol, sevoflurane, hypercapnia and hypocapnia on cerebral metaobolic rate and cerebrovascular tension directly or indirectly.