A new technique for total hepatectomy in the pig for testing liver supportdevices

Background. A large animal model of total hepatectomy is suitable to test t he efficacy of any system designed to support patients in hepatic coma. The models previously described in the pig entail a significant degree of surg ical trauma, which might alter the evolution of the ensuing hepatic failure and compromise the reproducibility of the model. Methods. Twenty-eight pigs underwent a total hepatectomy according to a new technique. A model was considered satisfactory when it required no blood t ransfusions and when hematologic and hemodynamic parameters determined befo re, during, and until 4 hours after hepatectomy showed no significant varia tions. Moreover, to revive the pattern of hepatic coma produced in the anhe patic model, 7 pigs were monitored until brain death occurred. Results. Twenty-five pigs (89%) underwent a smooth total hepatectomy with m inimal variations of the selected parameters. They constituted a highly hom ogeneous group. Survival of the 7 pigs, followed up until brain death occur red, ranged from 625 to 1595 minutes (mean 1013.57 minutes). The animals re mained stable until a few hours before brain death, an event heralded by a final sharp increase of the serum ammonia level and by a well-evident decli ne of both arterial pressure and liver-dependent clotting factors. Conclusions. This technique of total hepatectomy allows the construction of a reproducible model of anhepaty suitable to test the efficacy of any syst em conceived to temporarily replace hepatic functions.