monitored the method and apparatus keeps a biological entity such as an organ viable at a range of temperatures while in an aerobic state this allows the study of said organ from a physiological or experimental standpoint it allows said organ to be transplanted with little or no reperfusion injury thus increased survivability over the prior art application_number US 80466801 A description fig1 shows a frontal cross section view of a basic version an organ preservation apparatus in accordance with the preferred embodiment of the present invention fig2 shows the side cross section view of an organ preservation apparatus in accordance with the preferred embodiment of the present invention referring to fig1 and fig2 there are shown the main components consisting of a hyperbaric chamber 10 perfusate 12 a perfusate container 14 a pump 20 an oxygenator 24 an organ container 28 an organ biological entity 30 an oxygen source 38 and a cradle 48 it also shows fluid delivery tubes 18 22 26 32 through which a perfusate flows and various devices such as a pressure gauge 42 a biological filter 34 a chamber penetrator 36 a back pressure regulator relief valve 44 an oxygen line 40 and a decompression valve 46 the entire assembly is.