The Potential for Severe, Acute Inflammation to Impact Tissue Oxygenation—A Narrative Review

Arguably, the most vital function of the cardiovascular system (CVS) is its ability to facilitate the oxygenation of blood in the lungs, and to deliver that oxygen to the rest of the body. This relies on the ability of oxygen to diffuse in and out of the bloodstream, as well as for the CVS to maintain adequate perfusion of body tissues. The CVS also plays a key role in immune responses, particularly in initiating an acute inflammatory reaction in response to infection or injury. Changes in vascular function, such as vasodilation, increased vascular permeability, and initiation of coagulation, are critical elements of this inflammatory response. Normally, the regulated nature of immune responses helps to limit any potential detrimental effects. However, in cases of severe, dysregulated inflammation, as seen in conditions such as sepsis, the vascular responses that form a normal part of the inflammatory reaction may start to impact upon tissue oxygenation. Increased microvascular permeability and the development of edema can impact upon oxygen diffusion, whilst tissue perfusion can be impacted at the level of both the micro- and macrocirculation. In severe cases, impaired perfusion and oxygen delivery to vital organs may lead to multiple organ system failure. An increased understanding of the impact of inflammation on vascular function may help elucidate novel therapeutic approaches to manage these critical care situations.