Interpatient heterogeneity in hepatic microvascular blood flow during vascular inflow occlusion (Pringle manoeuvre)

Background:Vascular inflow occlusion(VIO)during liver resections(Pringle manoeuvre)can be applied to reduce blood loss,however may at the same time,give rise to ischemia-reperfusion injury(IRI).The aim of this study was to assess the characteristics of hepatic microvascular perfusion during VIO in patients undergoing major liver resection.Methods:Assessment of hepatic microcirculation was performed using a handheld vital microscope(HVM)at the beginning of surgery,end of VIO(20 minutes)and during reperfusion after the termination of VIO.The microcirculatory parameters assessed were:functional capillary density(FCD),microvascular flow index(MFI)and sinusoidal diameter(SinD).Results:A total of 15 patients underwent VIO;8 patients showed hepatic microvascular perfusion despite VIO(partial responders)and 7 patients showed complete cessation of hepatic microvascular perfusion(full responders).Functional microvascular parameters and blood flow levels were significantly higher in the partial responders when compared to the full responders during VIO(FCD:0.84±0.88 vs.0.00±0.00 mm/mm2,P<0.03,respectively,and MFI:0.69–0.22 vs.0.00±0.00,P<0.01,respectively).Conclusions:An interpatient heterogeneous response in hepatic microvascular blood flow was observed upon VIO.This may explain why clinical strategies to protect the liver against IRI lacked consistency.