Effects of low level of positive end expiratory pressure on cerebral hemodynamics in patient undergoing laparo-scopic radical gastrostomy with general anesthesia

Abstract

Objective To observe the effects of low levels of positive end expiratory pressure on cerebral hemodynamics in patients with gastric cancer undergoing laparoscopic radical resection surgery under general anesthesia. Methods 80 patients(ASAⅠ-Ⅱ), scheduled to undergo laparoscopic radical gastrostomy, were randomly divided into group A, and group B, each group had 40 cases. The ventilation parameters of group A:tidal volume(VT): 8 ml/kg, respiratory rate(RR): 12 min, positive end expiratory pressure (PEEP):5 cm H2 O(1 cm H2 O= 0.098 kPa). Group B was:VT:8 ml/kg, RR:12 min.Recording the average blood flow velocity in the middle cerebral artery(Vm),mean arterial pressure(MAP),heart rate(HR), transcutaneous oxygen saturation(SpO2),end-tidal carbon dioxide pressure(PetCO2)of the two group before pneumoperitoneum(T0),30 min after pneumoperitoneum(T1), 1 hours(T2)and 2 hours(T3)after pneumoperitoneum. Blood samples of jugular bulb and radial artery were obtained at each time point for blood gas analysis, detection the arterial oxygen pressure(PaO2), arterial carbon dioxide pressure(PaCO2), arterial oxygen saturation(SaO2), hemoglobin concentration(Hb), internal jugular venous blood oxygen partial pressure(PjvO2), internal jugular venous oxygen saturation(SjvO2), jugular venous oxygen content(CjvO2), and arterial-jugular venous oxygen content difference(Da-jvO2). Results Compared with T0,the Vm,SjvO2, PaCO2 of the two groups increased significantly at each time point(P<0.05).But the Vm, SjvO2 of group A at T2 was significantly lower than that in group B(P<0.05),and the PaCO2 of group A at T1 and T2 were(35.5±2.7),(40.7±3.5)mm Hg respectively, which significantly lower than that of group B [(39.9±3.1),(49.4±4.7)mm Hg,P<0.05].And the Vm of group A at T2 was(68.9±8.1)cm/s,significantly lower than that of group B(P<0.05).Compared with T0, the Da- jvO2 at T2 of two groups decreased significantly(P<0.05),and between the two groups, A group decreased significantly than that in B group(P<0.05). Conclusion The low level of positive end expiratory pressure in patients undergoing laparoscopic radical gastrostomy with general anesthesia can effectively reduce the hypercapnia during operation, and improve cerebral hyperperfusion state,so as to improve the cerebral blood flow and improve cerebral oxygen supply and demand balance. Key words: Positive end expiratory pressure; Laparoscopy; Radical gastrectomy; Cerebral hemodynamics