The impact of fever and its management in different medical and surgical populations of critically ill patients has not been explained to date. Clinical trials in critically ill surgical patients have demonstrated null or potentially harmful effects of treatment of moderate degrees of fever. However, the pathophysiological effects of fever treatment are not well defined according to different patient populations, and clinical trial results are questionably generalized to medical ICU patients. This may relate to different mechanisms of fever in these populations and merits further investigation. There is also very little known about the exact timing of expression of the diverse pro and anti-inflammatory mediators involved in inducing, maintaining and eventually abrogating the fever response. Treating on the sole basis of an elevated temperature may lead to detrimental effects if the anti-inflammatory cascade naturally regulating this response is active, demonstrating the importance of understanding the normal pattern of regulation of these diverse mediators. The current study aims to assess the safety and efficacy of treatment of critically ill patients with a permissive versus aggressive fever treatment strategy. In addition, the effect of anti-pyretic therapy on markers of inflammation in neurologically intact critically ill adults will be evaluated.