Meanwhile, it could also be demonstrated that IP prior to sustained warm ischemia can protect parenchymal and non-parenchymal liver cells by increasing the tolerance against I/R-related organ hypoxia under experimental as well as clinical conditions[13-16]. An important selleckbio observation was also that IP in human liver surgery was associated with better intraoperative hemodynamic stability, particularly on reperfusion of warm ischemic livers[17]. Although the underlying protective mechanisms of IP are still not fully understood[18], some studies have shown that the activation of Kupffer cells, leucocytes and the release of cytotoxic mediators on reperfusion may lead to a substantial breakdown of the hepatic microcirculation, an event which seems to play a key role following warm and cold ischemia[19-21].
For example, Klar et al[22] observed an inverse correlation between the hepatic microvascular blood flow rate and the maximum postoperative enzyme release from the liver. On the other hand, in healthy livers, a balanced portal vein (PV) and hepatic artery (HA) inflow are significantly dependent on the arterial buffer response, an autoregulation system which influences the whole blood supply to the liver at the level of the hepatic arterioles and portal venules, and which is assumed to be predominantly the result of adenosine action[23,24]. At this time, there is evidence that IP improves the hepatic microcirculation after warm as well as cold ischemia, but the influence of PM and IP on macrocirculatory parameters have not been elucidated as yet.
In this study, we therefore investigated the hepatic inflow in patients undergoing liver resections with special regard to postischemic liver injury and patient outcome. MATERIALS AND METHODS Patients and randomization The study was approved by the local Ethics committee and written informed consent was obtained from each patient before randomization. We investigated 116 consecutive patients at our institution who were subjected to liver resection (time period 12 mo). Of these, only 68 patients could randomly be assigned according to the inclusion criteria. These were defined as ��significant�� hepatectomies, i.e. removal of at least one segment.
A total of 48 patients were excluded from randomization for the following reasons: (1) extent of liver resection less than one segment according to Couinaud (n = 16); (2) anticipated necessity of total vascular exclusion (n = 8); (3) necessity of additional surgical procedures such as bilioenteric anastomosis or associated gastrointestinal procedures (n = 3); (4) laparoscopic liver resection GSK-3 (n = 10); (5) underlying liver cirrhosis (n = 9); and (6) emergency surgery (n = 2). Of the 68 randomized patients, 7 were withdrawn from the analysis because of intraoperative detection of inoperability.