Effects of low tidal volume combined with low level positive pressure at expiratory end on cognitive function of elderly patients received laparoscopic radical gastric resection in propofol anesthesia

【Objective】To evaluate effect of low tidal volume combined with low level of positive pressure at expiratory end on the cognitive function received laparoscopic radical gastric resection in propofol anesthesia.【Methods】80 cases of elderly patients with gastric cancer were elected by laparoscopic radical gastrectomy under general anesthesia in a period time, aged 65 to 80 years old, ASA grade I or grade II. Using the random number table, the patients were randomly divided into 2 groups(n =40): they were conventional ventilation group(A group)and low tidal volume and positive pressure expiratory end ventilation group(B group). A group of ventilation parameters were VT, 9 ml/kg, 12 RR /min, breath rate: 1∶2, B group of ventilation parameters were VT 6 ml/ kg, 16 RR /min, breath rate: 1∶2, positive end expiratory pressure(PEEP) was 5 cm H2 O. Their blood samples were collected and blood gas was analyzed by radial artery and jugular venous bulb before pneumoperitoneum(T0), one hour after pneumoperitoneum(T1), two hours after pneumoperitoneum(T2), three hours after pneumoperitoneum(T3), they were calculated arterial jugular venous oxygen content difference(Da-jv O2), cerebral oxygen extraction rate(CERO2), intraoperative peak airway pressure(Ppeak), arterial partial pressure of carbon dioxide(Pa CO2) and mean arterial pressure(MAP) and hemodynamic parameters, central venous pressure(CVP). Cognitive function was accessed with the mini mental state examination(MMSE) score on one day before operation, one day postoperative, and one week after operation. 【Results】Compared with A group B group was decreased at each time point, T1-T3 Da-jv O2 and CERO2Ppeak, Pa CO2, MAP, CVP was not significant statistically difference between the two groups, MMSE scores were increased in postoperative, incidence of cognitive dysfunction were decreased(P 0.05) in postoperative.【Conclusion】Cerebral oxygen metabolism was better with low tidal volume combined with low level of positive pressure expiratory end in laparoscopic radical gastrectomy for gastric cancer in elderly patients during the propofol anesthesia, and reduced effect of cognitive function after operative.