***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 included four trials with 271 patients undergoing open liver resections. The patients were randomised to ischaemic preconditioning (n = 135) and no ischaemic preconditioning (n = 136) prior to continuous vascular occlusion (portal triad clamping in three trials and hepatic vascular exclusion in one trial). All the trials excluded cirrhotic patients. We assessed all the four trials as having high risk of bias. There was no difference in mortality, liver failure, other peri-operative morbidity, hospital stay, intensive therapy unit stay, and operating time between the two groups. The proportion of patients requiring blood transfusion was lower in the ischaemic preconditioning group. There was also a trend towards a lower amount of red cell transfusion favouring ischaemic preconditioning group. There was no difference in the haemodynamic changes, blood loss, bilirubin, or prothrombin activity between the two groups. The enzyme markers of liver injury were lower in the ischaemic preconditioning group on the first post-operative day. Currently, there is no evidence to suggest a protective effect of ischaemic preconditioning in non-cirrhotic patients undergoing liver resection under continuous vascular occlusion. Ischaemic preconditioning reduces the blood transfusion requirements in patients undergoing liver resection.
Output:

The aim of this review was to assess the role of ischaemic preconditioning in liver resections performed utilising vascular occlusion. Four randomised clinical trials including 271 patients undergoing open liver resections fulfilled the inclusion criteria of this review. The patients were randomised to ischaemic preconditioning (n = 135) and no ischaemic preconditioning (n = 136) prior to continuous vascular occlusion. All the trials excluded cirrhotic patients. We assessed all the four trials as having high risk of bias (high risk of systematic error). There was no difference in mortality, liver failure, post-operative complications, hospital stay, intensive therapy unit stay, and operating time between the two groups. The proportion of patients requiring blood transfusion was lower in the ischaemic preconditioning group. The reasons for this are not clear. There was no difference in blood loss or enzyme markers of liver function between the two groups. The enzyme markers of liver injury were lower in the ischaemic preconditioning group on the first post-operative day. Currently, there is no evidence to suggest a protective effect of ischaemic preconditioning in non-cirrhotic patients undergoing liver resection under continuous vascular occlusion. Ischaemic preconditioning reduces the blood transfusion requirements in patients undergoing liver resection. Further high quality randomised clinical trials are necessary to assess the role of ischaemic preconditioning. Further studies are necessary to understand the mechanism of ischaemic preconditioning.