Development of a minimally invasive microvascular ischemia monitor: clinical detection of ischemia

The objective of our research is to develop a pH based, microvascular measuring system which will be used for accurate postoperative monitoring of transplanted tissue. Currently, most pH monitors that are used for this purpose are difficult for hospital personnel to operate and do not possess sufficient long-term stability, resulting in false readings of tissue pH. An electronic multi-channel pH measuring device which interfaces with a laptop computer was constructed. The system makes use of an algorithm to compensate for inherent pH measurement instabilities. This is accomplished using separate pH reference electrode channels from which multiple measurements are averaged. Preliminary tests show that this system accurately measures tissue pH and is sufficiently stable during the 96 hour postoperative monitoring period.