Abstract:
Early reperfusion of orthotopic liver transplantation is characterized by hemodynamic instability, microvascular disturbance and impaired tissue oxygenation which may contribute to graft failure. In previous studies it was possible to show that the artificial oxygen carrier DClHb (HemassistTM) as well as the hypertonic-isooncotic solution HyperHes(R) (HHES) can decrease ischemia-reperfusion injury, increase tissue oxygenation and restore central hemodynamics. It was the aim of this study to examine the effect of 4 ml/kg body weight DClHb or HHES vs. 6% HAES-steril(R) (200000/0,5) on hemodynamics, regional blood flow and oxygen transport in a pig model of orthotopic liver transplantation. We performed 44 liver transplantations, the surgical and anaesthesiologic method was similar to the clinical management. The test medication was given five minutes prior to reperfusion. We applicated fluorescent Microspheres before and during the anhepatic stage and three times after reperfusion to examine the regional blood flow of the stomach, the small intestine, the liver and the kidneys. The gastric intramural pH (pHi) and the hepatic venous O2-saturation were used as indirect parameter of the gastrointestinal perfusion.
HHES showed better results after reperfusion on central hemodynamic parameters than DClHb or HAES-steril(R). Mean arterial blood pressure and cardiac index were normalized, the required amount of catecholamines was reduced. DclHb diminished the cardiac index and elevated the mean pulmonal-arterial pressure considerably. However, less catecholamines were necessary to maintain the systemic circulation after DClHb compared to HAES-steril(R).
An improvement of the gastrointestinal perfusion and the regional oxygen delivery (DO2) were only found with HHES. The artificial oxygen carrier DClHb elevated the oxygen content. However, oxygen delivery was reduced due to the decrease of the cardiac index. The local NO-scavenging- and endothelin-releasing effects of DClHb may contribute to the reduced regional oxygen delivery, too. The renal perfusion and its oxygen delivery were similar in all groups. HHES improved direct and indirect metabolic parameters (pHi, ABE, lactate) more strongly and than DClHb or HAES-steril(R).
The hepatic perfusion after HHES was more physiologic compared to the other test groups . We found less low/no-reflow-areas and an elevated hepatic venous O2-saturation after HHES.