Abstract
This chapter reviews recent experimental studies concerning the detrimental consequences of hyperthermia on ischemic outcome. The chapter also discusses potential mechanisms underlying the detrimential consequences of mild hyperthermia. Fever is frequently observed following cardiopulmonary resuscitation and is considered prognostic of poor outcome in patients with acute stroke. In acute stroke patients, hyperthermia during the first 7 days is an independent predictor of poor outcome. Experimental studies using animal models of cerebral ischemia have provided novel data concerning the importance of brain temperature on ischemic outcome. While mild to moderate levels of brain and/or whole body hypothermia provide neuroprotection, mild elevations in temperature worsen outcome. Clinical and experimental data indicate that mild elevations in brain temperature during or following an ischemic insult may adversely affect the temporal progression of the injury process as well as the final outcome. Thus, the therapeutic window for pharmacotherapy after an ischemic insult could potentially be shortened by mild temperature elevations. Postischemic hyperthermia may also be a secondary injury mechanism that could potentially affect outcome days after the primary insult. Because of the adverse effects of hyperthermia reported in experimental models, periods of fever could potentially negate the beneficial effects of pharmacotherapy.