The protective effects of induced hyperkalemia during total circulatory arrest

Three groups of adult mongrel dogs were subjected to 15 minutes of toal circulatory arrest. One group was infused with one liter of Krebs-Hensleit solution and kept normothermic, one group was infused similarly and their body temperature was lowered to 10 to 15 degrees C., and the third group was kept normothermic and infused with hyperkalemic solution. Adenosine triphosphate (ATP) and creatine phosphate levels in the brain during and after the ischemic period were not significantly different in the three groups and glycogen levels tended to remain higher in the hypothermic group. None of the normothermic dogs survived, but all of the hypothermic and hyperkalemic animals survived and were grossly normal. These data indicate that hyperkalemai does offer some protection to the brain during periods of circulatory arrest. It also appears that survival and persistence of brain function do not correlate necessarily with levels of high energy compounds in the brain.