***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: We identified three trials with high risk of bias which compared veno-venous bypass (n = 65) versus no veno-venous bypass (n = 66). None of the trials reported patient or graft survival. There were no significant differences regarding renal failure or blood transfusion requirements between the two groups. None of the trials reported on the morbidity related to veno-venous bypass or the requirement of veno-venous bypass in the control group. We identified one trial with high risk of bias which compared percutaneous (n = 20) versus open technique (n =19) of veno-venous bypass. The patient or graft survival was not reported. There was no difference in veno-venous bypass related morbidity between the two groups. The operating time was significantly shorter in the percutaneous technique group (MD -59 minutes; 95% CI -102 to -16). There is no evidence to support or refute the use of veno-venous bypass in liver transplantation. There is no evidence to prefer any particular technique of veno-venous bypass in liver transplantation.
Output:

We systematically searched various medical databases to determine whether veno-venous bypass is required routinely during liver transplantation. We identified a total of three randomised clinical trials with high risk of systematic error and high risk of random errors which compared veno-venous bypass (n = 65) with no veno-venous bypass (n = 66). None of the trials reported patient or graft survival. There were no differences regarding kidney failure or blood transfusion requirements between the two groups. None of the trials reported on the complications related to veno-venous bypass or the requirement of veno-venous bypass in the control group. We also identified one trial with high risk of systematic error and high risk of random errors which compared needle technique (percutaneous approach) (n = 20) with open technique (n =19) of veno-venous bypass. The patient or graft survival was not reported in this trial. There was no difference in veno-venous bypass related complications between the two groups. The operating time was shorter in the percutaneous technique group. There is currently no evidence to support the routine use of veno-venous bypass in liver transplantation.