Intraperitoneal microdialysis (IPM): a new technique for monitoring intestinal ischemia studied in a porcine model.

Acute mesenteric thrombosis, vascular complications of intestinal transplantation, sepsis, and multiple organ failure are all associated with intestinal ischemia. To improve the outcome of these patients, better monitoring devices are needed. A new technique, intraperitoneal microdialysis (IPM), was evaluated for detection of intestinal ischemia in a porcine model, with the intention of evaluating the technique for future use on humans. Fourteen pigs divided into two studies were used. In a total ischemia study a microdialysis catheter was placed intraperitoneally and the superior mesenteric artery was occluded for 1 h 40 min. In a local ischemia study, the arcus vessels supplying a 30-cm long small bowel segment were occluded for 3 h 20 min. One IPM catheter was placed next to the ischemic area and another IPM catheter 10 cm caudally as an intraperitoneal reference. In both studies reference catheters were placed subcutaneously. Glucose, lactate, pyruvate, and glycerol were analyzed every 20 min. In both studies vessel occlusion resulted in decreased glucose and increased lactate, glycerol, and lactate/pyruvate ratio. Significant changes were reached after 60 min of ischemia in most analytes, whereas the values from the reference catheter were stable. Our conclusion is that intestinal ischemia is detectable with IPM based on the analysis of well-documented markers of ischemia (increased lactate/pyruvate ratio) and cell membrane damage (elevated glycerol levels). It allows semi-continuous monitoring of the intestines with a minimally invasive procedure, which we believe will be possible to apply in human routine clinical use.