NOMI and pathophysiology. (1) Cardiac arrest is a serious condition for which CPR is the solution. (2) During CPR, hypoperfusion of all organs, including the intestine, occurs. (3) Intestinal villi are very vulnerable to IR damage due to the arrangement of the vascular supply to the villi. (4) During IR injury, the endothelial structure of the villi is disrupted, and some substances are absorbed into the bloodstream and detectable in the serum. (5) The diagnosis is based on the detection of these serum markers. (6) The degree of IR damage reflects the severity of the hypoperfusion and hypoxia, the intensity of SIRS, and can be used to assess neurological prognosis. CPR, cardiopulmonary resuscitation; IR, ischemia-reperfusion; SIRS, systemic inflammatory response syndrome; I-FABP, intestinal fatty acid-binding protein; NOMI, non-occlusive mesenteric ischemia; pO2, partial pressure of oxygen. Created with https://www.biorender.com/.