Effect of different tidal volume and low level of positive end expiratory pressure on respiratory function in patients with general anesthesia of laparoscopic surgery

Objective To analyze the effect of different tidal volume and low levels of end expiratory positive pressure ventilation on respiratory function in laparoscopic surgery under general anesthesia, to provide reference for the selection of ventilation modes of laparoscopic operation in general anesthesia. Methods Ninety-six patients who received general anesthesia were selected from August 2013 to June 2016. According to the random number table method, they were divided into observation group (n=48) and control group (n=48). Mechanical ventilation after tracheal intubation was performed in the two groups, and tidal volume was 9 ml/kg and respiratory frequency was 12 times/min before pneumoperitoneum, after pneumoperitoneum, the tidal volume changed to 6 ml/kg, respiratory frequency changed to 14 times/ min in observation group, but the ventilation parameters of control group were unchanged. The heart rate (HR), mean arterial pressure (MAP), arterial oxygen partial pressure (PaO2), arterial carbon dioxide partial pressure (PaCO2), end expiratory carbon dioxide partial pressure (PetCO2), Alveolar arterial oxygen partial pressure (A-aDO2), oxygenation index and respiratory index, jugular venous oxygen points pressure(PjvO2), internal carotid venous oxygen saturation(SjvO2), jugular venous oxygen content (CjvO2), cerebral arterial venous oxygen content difference (Da-jvO2) index were compared between the two groups before pneumoperitoneum, 30 min after pneumoperitoneum and 60 min after pneumoperitoneum. Results Before pneumoperitoneum, 30 min after pneumoperitoneum and 60 min after pneumoperitoneum, HR and MAP of the two groups had no statistically significant difference(P>0.05); 30 min and 60 min after pneumoperitoneum, PaO2, PaCO2, PetCO2, A-aDO2, oxygen index and respiratory index of observation group were better than those of control group, the differences were significant (P<0.05); 30 min and 60 min after pneumoperitoneum, PjvO2, SjvO2 and CjvO2 of observation group were higher than those of control group, Da-jvO2 was lower than that of control group, and the differences were significant (P<0.05). Conclusions Low tidal volume and low levels of end expiratory positive pressure ventilation can improve the respiratory function and cerebral oxygen metabolism in patients with general anesthesia of laparoscopic surgery, and has a high practical value, it is worth popularization and application. Key words: Anesthesia; Low level of positive end expiratory pressure; Tidal volume; Respiratory function