In elective liver resection, hepatic vascular occlusion cannot be recommended over portal triad clamping. Intermittent portal triad clamping seems to be better than continuous portal triad clamping at least in patients with chronic liver disease. There is no evidence to support selective inflow occlusion over portal triad clamping. The optimal method of intermittent portal triad clamping is not clear. There is no evidence for any difference between the ischaemic preconditioning followed by vascular occlusion and intermittent vascular occlusion for liver resection in patients with non-cirrhotic livers. Further randomised trials of low risk of bias are needed to determine the optimal technique of vascular occlusion.
The effect of hepatic vascular inflow occlusion on liver tissue pH, carbon dioxide, and oxygen partial pressures: defining the optimal clamp/release regime for intermittent portal clamping.
The optimal duration of hepatic vascular inflow occlusion (Pringle maneuver) and reperfusion during liver resection are not defined. The aim of this study was to describe the changes that occur in liver tissue pH, partial pressure of carbon dioxide (P(L)CO(2)), and partial pressure of oxygen (P(L)O(2)) and by using the P(L)CO(2) as a predictor of hepatocellular damage define the optimal clamp/release regime for intermittent portal clamping during liver resection.
                Continuous pH, P(L)CO(2), and P(L)O(2) measurements were obtained using a Paratrend multi-parameter sensor (Diametrics Medical Inc., Roseville, MN) in 13 patients undergoing elective partial liver resection. Patients were randomly allocated to undergo a 10-min clamp/5-min release regime (group 1) or a 20-min clamp/10-min release regime (group 2).
                In group 1 (n = 6) P(L)CO(2) increased and pH decreased significantly after 10 min of clamping and returned to baseline within 5 min of reperfusion. In group 2 (n = 7) the P(L)CO(2) increased and pH decreased significantly after 10 min of clamping, with a further significant change after 20 min. Following 10 min of reperfusion, pH and P(L)CO(2) had not returned to baseline. P(L)O(2) did not change significantly with either intermittent portal clamping regime.
                A reperfusion of 5 min is sufficient to restore the P(L)CO(2) and liver tissue pH to normal after 10 min of clamping, but more than 10 min of reperfusion is required after 20 min of clamping. To minimize hepatic ischemia during liver resection, a 10-min clamp/5-min release regime should be used.