Clinical biochemical tissue monitoring during ischaemia and reperfusion in major vascular surgery

Abstract

Background Major vascular surgery with aortic cross-clamping is associated with temporary ischaemia of the lower limb due to lack of tissue blood flow. The present study was designed to determine if the short-term changes in cellular metabolism occurring during this situation can be detected by subcutaneous microdialysis. It was also hoped to ascertain if this new technique is useful in the continuous bedside monitoring of metabolism during aortic surgery.

Urea Clearance: A New Technique Based on Microdialysis to Assess Liver Blood Flow Studied in a Pig Model of Ischemia/Reperfusion

“…Traditionally, the lactate:pyruvate ratio has been used in various research protocols as a reliable marker for ischemia [24,25] , particularly in the liver [26,27] . Recently, the lactate:glucose ratio has been suggested to be a more sensitive marker of ischemia as glucose is readily consumed when the supply is diminished [28] . This, however, does not apply in the liver as liver glucose levels are increased during the ischemic phase.…”

Blood, sweat, and tears: developing clinically relevant protein biosensors for integrated body fluid analysis

“…[149][150][151] The implanted MD probe is perfused with an isotonic liquid that collects molecules below the MWCO of the membrane through diffusion, which can then be collected and analysed. Since the pioneering work of Jansson et al 149 and Anderson et al 150 in the late 1980's MD has been extensively used for the measurement of small molecules, [152][153][154] whilst some high molecular weight molecules have also been detected, including cytokines (IL-6 ∼ 29 kDa), 154 albumin, 155 and high molecular weight dextrans (in vitro only, up to 150 kDa). 156 Sampling of large molecules is somewhat limited, however, due to the loss perfusate from probes with very large effective pores, reducing sample recovery.…”

Significant [C3a] Increase in Free Flaps After Prolonged Ischemia

“…Concerning the metabolic parameters, glucose is bypassing the citrate cycle and will be metabolized via pyruvate into lactate during ischemia. Therefore, ischemically injured tissue will deplete glucose and increase amount of lactate [34]. In our study, we were able to detect a nonsignificant trend from low flap levels during ischemia to equal glucose levels in flap and reference tissue after reperfusion ([tissue F ]/ [tissue C ] ϳ 1), also lacking a significant difference between both groups A and B. Tissue concentration of lactate and pyruvate was not altered significantly in both groups during ischemia and reperfusion period.…”