Effect of laparoscopic surgery CO2 pneumoperitoneum for colorectal cancer on femoral venous hemodynamics WANG Yu*，WANG Yan-ting，JIANG Yan-yan，et al.*Department of General Surgery，Fuzhou General Hospital of Nanjing Military Command，Fuzhou 350025，China Corresponding author:ZOU Zhong-dong,E-mail: fzptwk@21cn.com Abstract Objective To study the effect of the special surgical position and CO2 pneumoperitoneum on femoral venous hemodynamics during laparoscopic surgery for colorectal cancer.Methods Color Doppler ultrasound was adopted to evaluate the diameter、blood velocity and volum of the blood flow in the lower extremity with 30 patients undergoing laparoscopic surgery for colorectal cancer in Fuzhou General Hospital of Nanjing Military Command between August 2007 to June 2008,with different pressure of pneumoperitoneum（6mmHg、8mmHg、10mmHg、12mmHg）and that during the laparoscopic surgery for colorectal cancer with 12mmHgCO2 pneumoperitoneum and head-down tilt position. Results Compared with the stage before the pneumoperitoneum, no change was obserbed with the hemodynamics indexes after the establishment of 6mmHgCO2 pneumoperitoneum；when the pressure of pneumoperitoneum increases to 8mmHg, the femoral vein diameter increases、 the velocity and the amount of blood flow decrease by degrees (P<0.05) with the accrescence of pneumoperitoneum pressure. During the operation, the femoral vein diameter decreased，the velocity and the volum of blood flow increased with the head-down tilt position,but still less than the level before pneumoperitoneum, compared with the stage of prostration after pneumoperitoneum,;At the end of operation without the exhaust of CO2 gas,the femoral vein diameter returned to the level of the prostration after pneumoperitoneum, while the velocity and the volum of blood flow was still higher than that, but significantly lower than that of feet-down tilt position with pneumoperitoneum; At the end of operation with prostration and the exhaust of CO2 gas , the femoral vein diameter decreased,but still thicker than prostration without pneumoperitoneum,and the velocity and the volum of blood flow returned to the level before pneumoperitoneum. Conclusion The CO2 pneumoperitoneum can interfere the recirculation of blood，positive correlated to the pressure,witch will increase the risk of venous thrombosis ,so we should take the lower-grade of pneumoperitoneum pressure as far as possible . Besides, the head-down tilt position is conducive for the blood to recirculate ,which can improve but not fully offset the poor blood returning conducted by CO2 pneumoperitoneum .The vein stasis exists objectively in the perioperation of laparoscopic colorectal cancer operation, which will increase the risk of venous thrombosis ,and taking the active preventive measures is requisite.