Tissue oxygenation in sepsis; new insights from in vivo EPR

Nitric oxide (NO) is a key mediator in the maldistribution of oxygen by tissue and organ dysfunction observed in sepsis. Despite this, few techniques are capable of measuring these parameters directly in vivo. We describe here several techniques that have been developed by our group to address this directly by in vivo EPR in animal models of sepsis. Oxygen-sensitive materials can be implanted or administered and report on local tissue pO₂. Spin trapping of NO can simultaneously report on tissue NO content. Repeat measures of these parameters can be made directly from a defined tissue site, allowing development of new models and experiments to study the defects in tissue and organ function seen in sepsis.