Experimental study on the establishment and maintenance of brain death model with pigs

It remains controversial that after the transplantation of using grafts from brain-dead donors, organs injury and rejection can influence the effects of transplantation. This study sought to explore methods of establishing a stable brain death (BD) model using Bama mini pigs and to maintain the brain-dead state for a comparatively long period to provide a model for investigating changes in brain death. Sixteen anesthetized Bama mini pigs were randomized into a control group (n = 5) and a BD group (n = 11). Intracranial pressure (ICP) was increased in a modified, slow, and intermittent way to establish BD. Respiration and circulation were sustained during the brain-dead state. Hemodynamic changes were monitored during the experiment. In the BD group, 10 pigs met the requirements for brain death and 1 died of cardiopulmonary complications following an increase in ICP. Brain death was maintained for more than 48 hours with artificial life support. During the experiment, the heart rate and blood pressure showed characteristic changes due to increased ICP. Prior to BD being established, a "tic reaction" inevitably occurred. We used an improved method of increasing ICP to establish a stable BD model. The BD state could be maintained for more than 48 hours with effective respiratory and circulatory support. Disappearance of the tic reaction was considered to be one of the verified indexes for BD via encephalic pressure increase.