Perfluoro tert-butylcyclohexane (PTBCH) is a perfluorocarbon emulsion that acts as a highly effective oxygen carrier compared to blood. Administration of PTBCH significantly increased parenchymal tissue oxygen levels during the usual post-injury hypoxic phase, and PTBCH has been shown to be effective in stroke and head injury. Administration of PTBCH during cardiopulmonary bypass was associated with an excessive release of cytokines. This enhanced inflammatory response with subsequent hypotension may have contributed to mortality in rats receiving PTBCH. The observed patterns of myocardial injury indicate global hypoperfusion and catecholamine excess.