Organperfusion

Organ perfusion is the process of delivering blood or an appropriate fluid to an organ to maintain tissue viability, oxygenation, and metabolic waste removal. In living systems, physiological perfusion is driven by the cardiovascular system and regulated to match tissue demand. In medical practice, perfusion concepts are applied during organ preservation, transplantation, and critical care.

In vivo perfusion relies on the arterial supply and venous drainage to sustain organ function. Parameters such as arterial pressure, flow, temperature, and oxygen tension influence microcirculatory flow and cellular metabolism. Both pulsatile and nonpulsatile flow can be used, depending on the organ and clinical context.

Ex vivo organ perfusion uses machine perfusion technology to perfuse an extracted organ with an oxygenated solution. This approach can be hypothermic, normothermic, or subnormothermic, each with different aims from preservation to functional assessment. Normothermic machine perfusion maintains near-physiological temperature and metabolism, while hypothermic approaches reduce metabolic demand. Perfusion solutions may be acellular or contain red blood cells or hemoglobin-based oxygen carriers and are supplemented with nutrients, electrolytes, and anti-inflammatory additives.

Applications include preservation of kidneys, liver, heart, lungs, and pancreas for transplantation, with the goal of reducing ischemia-reperfusion injury and expanding the donor pool. Ex vivo perfusion also allows viability assessment and therapeutic intervention prior to implantation.

Limitations include technical complexity, equipment cost, risk of contamination, and the lack of universally accepted viability criteria. Ongoing research seeks optimized perfusates, oxygen carriers, and molecular biomarkers to improve outcomes and standardize practice.