To clamp or not to clamp: Inflow occlusion during liver resection Yue-Sun Cheung,* Kit-Fai Lee, Siu-Wang Wong, Ching-Ning Chong, John Wong and Paul Bo-San Lai Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong. Aim: To review the evidence in using inflow occlusion during liver resection. Other strategies to minimize the untoward effects of inflow occlusion will also be discussed. Methods: Randomized trials evaluating the use of inflow occlusion in hepatectomy and strategies to mini- mize its associated adverse effects were reviewed in this article. Recent experience showing comparable operative outcomes without the use of portal clamping was also described. Results: Results from randomized trials and meta-analyses were not conclusive on the benefits of routine inflow occlusion during liver resection. Intermittent inflow occlusion and ischaemic preconditioning had been found to be effective in reducing ischaemic–reperfusion injury to remnant liver. With refined operative tech- niques and better instruments, routine inflow occlusion in liver resection can now be safely avoided. Conclusion: Vascular inflow occlusion is an important armamentarium during liver resection, but it should not be used indiscriminately. With refined techniques and better instruments, hepatectomy can be performed safely without the need for routine inflow occlusion. Key words: hepatectomy, inflow occlusion, portal clamp, Pringle manoeuvre, review. Introduction Liver resection is a technically demanding operation because of the complexity of liver anatomy, vascularity of liver parenchyma and in some of the patients, the associated liver fibrosis and cirrhosis. It used to be a procedure associated with massive blood loss, 1 high morbidity and mortality rate, 2 and was considered a high-risk operation for both patients and surgeons. With the advance of surgical techniques and peri- operative care, the morbidity and mortality of liver resection has been decreasing in recent years. More accurate preoperative assessment, perioperative nutrition support, intraoperative strategies to decrease blood loss and transfusion, advancement in instru- ments, intensive care, understanding of liver anatomy and surgical training have contributed to the improve- ment in operative outcome. 3 Although liver resection is better tolerated nowa- days, with relatively good results, bleeding is still a major hazard. Massive bleeding and transfusion have been shown to be associated with poorer outcome in hepatectomy. 4,5 Inflow occlusion of the portal triad, also known as portal triad clamping and Pringle manoeuvre, was first described by James Hogarth Pringle during surgery for liver trauma more than 100 years ago. 6 It is a well-studied method to reduce blood loss during liver resection, and is commonly employed by many liver surgeons. The aim of this article is to review the evidence in using inflow occlusion during liver transection. Other strategies to minimize the untoward effects of inflow occlusion will also be discussed. Evidence in portal triad clamping There were four randomized, controlled trials compar- ing inflow occlusion and no portal clamping during hepatectomy. Only one trial included patients with continuous clamping, while all other three trials adopted intermittent clamping. In the two studies by Man et al., 7,8 the Pringle manoeuvre was associated with significantly less blood loss and a lower blood transfusion rate. However, there were no difference in hospital mortality and morbidity. In the study by Chouker et al., 9 patients were divided into three arms: continuous clamping, continuous clamping with ischaemic preconditioning and the no clamping arm. There were less than 20 cases in each arm. This study *Author to whom all correspondence should be addressed. Email: yuesun@surgery.cuhk.edu.hk Received 27 January 2011; accepted 14 April 2011. Surgical Practice doi:10.1111/j.1744-1633.2011.00562.x Review Article Surgical Practice (2011) 15, 128–131 © 2011 The Authors Surgical Practice © 2011 College of Surgeons of Hong Kong