Tutorial System is beneficial to improving the general disposition of undergraduate students,forming better learning atmosphere,enhancing the scientific research ability,broadening the pathway of contacting society,developing students' cognitive ability,and strengthening employment instructive work.Tutorial system for undergraduate students has been carried out for 4 years in our military medical university.After finding some problems of the work,making a summary of the beneficial experience and analyzing the cause of problems,we try to put forward some suggestions and take some optimization measures.

Objective: To evaluate the effect of plasma exchange combined with high-dose continuous venovenous hemodiafiltration method (CVVHDF) in the treatment of patients with acute-on-chronic liver failure with stage III-IV hepatic encephalopathy and the feasibility of pre-operative preparation for liver transplantation. Methods: Clinical data of 14 cases of medical intensive care unit of our hospital with acute-on- chronic liver failure accompanied with stage III-IV hepatic encephalopathy that underwent plasma exchange combined with high-dose CVVHDF from March 2015 to September 2017 were retrospectively summarized. The indexes of liver and kidney function, blood coagulation function, arterial blood PH, lactic acid and blood ammonia were monitored before and after treatment. Heart rate, blood pressure, APACHE II score, and consciousness recovery time were observed. Student’s t- test was used to compare the mean values between the two groups. Results: Serum total bilirubin (t = 9.43, P < 0.01), serum creatinine (t = 3.40, P < 0.01), serum ammonia (t = 10.64, P < 0.01), prothrombin activity (t = 9.19, P < 0.01), serum lactate (t = 9.25, P < 0.01), heart rate (t = 4.47, P < 0.01), and mean arterial pressure (t = 4.41, P < 0.05) were significantly improved in 14 patients before and after treatment. In addition, respiratory rate (t = 6.01, P < 0.01) and APACHE II score (t = 7.19, P < 0.01) were significantly improved (P < 0.05). Eight patients with stage III hepatic encephalopathy were treated with intermittent plasma exchange combined with CVVHDF for 3 to 14 days, and six patients with stage IV were transformed to stage III to II. Liver transplantation was successfully performed on 14 patients with shortest time duration of 3days, and longest time duration of 1 month. Conclusion Plasma exchange combined with CVVHDF can significantly improve liver and kidney functions, reduce blood ammonia level and improve mental health in patients with hepatic failure accompanied with stage III-IV hepatic coma. In addition, it also effectively increases the average arterial pressure, maintain stability of vital signs, maintain fluids, electrolytes and acid-base balance, create a stable internal environment for liver transplantation before operation, and extend time for liver transplantation.