Establishment and evaluation of a new severe hepatic trauma model

Objective To establish and evaluate a severe hepatic trauma model.Methods Eleven Chinese miniature swine for experiments were used in the current study.Using the self-made explosive-actuated device(MT-1),the explosive substance was prepared from 0.4 g black gunpowder and was placed on the diaphragmatic surface of the target hepatic lobe after the miniature swine had received celiotomy.Protective isolation for adjacent structure was then conducted,and then "fire".The parenchyma area(S) was destroyed,and the mean arterial pressure(MAP) and blood loss(V) were measured to evaluate the local injury of the model animals and the changes of hemodynamics after being injured.Results The area(S) of the destroyed parenchyma was 12.19±2.28 cm2.MAP presents the linear decline from 2 min to 7 min in the early stage post injury,with a decreasing rate of 6.58±2.30 mmHg/min and a period of 7.22±0.37 min when dropped to half.Blood loss was 466±79 ml when MAP drops to half of the level before injury.Treatment was not initiated for the first three animals and the time to death was between 23 min and 31 min.Conclusions The prepared model of severe hepatic trauma miniature swine corresponds with grade IV(AAST) in human.The current model can be used to study war and traffic accident traumas due to its good repeatability and strong controllability.