This study will be conducted in the surgical intensive care unit (SICU) at Yale New Haven Hospital in a prospective observational fashion. As this is a pilot study to determine the accuracy of CGM in our patient population we have based our enrollment projection to complete the study within an approximately 8 month time frame. We will identify three groups of 15 patients who are candidates for enrollment. The primary outcome is the degree of correlation between the continuous glucose monitor and capillary or arterial blood samples.