The Effect of Nitroglycerine on Microcirculatory Abnormalities During Sepsis

The purpose of this study is to evaluate the effect of nitro-glycerine on the microcirculation (smallest vessel type) in patients with severe sepsis and septic shock. Nitro-glycerine is a well known medicine in cardiology and is used to improve circulation. In this ICU the investigators use nitro-glycerine to improve the organ perfusion; but it's no common therapy in the rest of the world. The investigators now compare nitro-glycerine and placebo by looking to the sublingual microcirculation by a small camera (SDF imaging).