Changes in oxyhemoglobin dissociation curve in intrabdominal organs during pig experimental orthotopic liver transplantation.

Liver transplantation has become a gold standard treatment for irreversible liver disease. Conventional measures of oxygenation are inadequate to understand the dynamics of regional oxygen metabolism during liver transplantation because they represent global markers of tissue dysoxia. Therefore, the addition of an assessment of the hemoglobin O(2) binding capacity can give a better insight into systemic and regional tissue oxygenation and can reflect a more accurate estimation of oxygen release to the tissues than can the hemoglobin, the PaO(2) and SaO(2) alone. This prospective study was designed to evaluate possible alterations in the oxyhemoglobin dissociation curve of vital end organs (small bowel, liver, and kidney) in an experimental liver transplantation model. Fifteen pigs with body weights ranging from 25 to 30 kg were used for the study. Five healthy pigs underwent a sham operation under general anesthesia (group A-control). Ten pigs underwent orthotopic liver transplantation (OLT). Five of them were healthy (group B), whereas the other five were in acute liver failure, which had been surgically induced (group C). Systemic arterial blood pressure, cardiac index, and pulmonary and systemic vascular resistance indexes were measured. Venous blood gas analysis was also performed from pulmonary artery, superior mesenteric, hepatic, and renal veins at well-defined timepoints during the course of the OLT. A statistically significant (P < 0.05) decrease of P(50) in groups B and C compared with group A was observed 30 minutes after reperfusion in the systemic circulation, hepatic, and renal veins. This coincided with a decrease in animal temperature 30 minutes after reperfusion. Regarding group C, after reperfusion of the newly transplanted liver there was a significant increase of P(50) in the small bowel in comparison to baseline values. In conclusion, these changes in P(50) may suggest the occurrence of abnormal tissue oxygenation after reperfusion.