Normothermic organ preservation techniques maintain donated organs at near normal body temperature while supporting cellular activity and organ function. This approach uses specialized perfusion systems to circulate oxygenated, nutrient enriched fluids through organs outside the body. Unlike traditional cold storage, normothermic preservation aims to reduce cold related injury and provide opportunities for organ assessment before transplantation. Understanding its methods, applications, potential benefits, and limitations helps explain how advances in transplantation medicine are addressing organ shortages and preservation challenges. This article explores the scientific principles behind normothermic perfusion and its role in modern organ transplantation research and clinical practice.
Normothermic organ preservation is a technique that maintains donated organs at approximately normal body temperature while supplying oxygen and nutrients through a machine perfusion system. The approach is designed to support cellular metabolism and allow clinicians to evaluate organ function before transplantation. Traditional static cold storage reduces metabolic activity by lowering organ temperature, whereas normothermic perfusion aims to maintain a more physiologically active environment.
During normothermic machine perfusion, an organ is connected to a specialized circuit that circulates a perfusion solution through its blood vessels. Depending on the organ and system, the solution may contain oxygen, nutrients, electrolytes, and other components required to support tissue function.
Important aspects of this technique include:
Normothermic perfusion can be performed outside the body, known as ex situ perfusion. Normothermic regional perfusion is a related approach that supports organs within the donor's body under specific clinical protocols. These methods have different applications and technical requirements.
Normothermic preservation has been studied in liver, kidney, lung, and other organ transplantation settings. Its clinical role varies by organ because each tissue has different metabolic requirements, susceptibility to ischemic injury, and preservation challenges.
Liver transplantation has been an important area for the development of normothermic machine perfusion. Clinical studies have investigated its use for preserving organs, evaluating graft function, and improving the utilization of donated livers.
A major potential advantage of normothermic perfusion is the ability to assess organ function while the organ remains connected to a controlled perfusion system. Depending on the organ, medical teams may monitor parameters such as blood flow, oxygen consumption, metabolic markers, and urine production.
Research in liver transplantation has reported improvements in certain early outcomes and organ utilization measures compared with static cold storage. However, results differ between organs and clinical protocols.
Normothermic preservation requires specialized equipment, trained personnel, perfusion solutions, and continuous monitoring. The technique can involve substantial logistical and operational requirements.
For example, a 2025 study investigating prolonged normothermic perfusion of human donor kidneys reported feasibility and favorable short term graft survival in a phase 1 cohort. Further studies are needed to establish how different preservation protocols affect long term outcomes.