常温局部灌注在受控心脏死亡肝移植供体中的应用

目前全球器官移植领域所面临的仍是供体短缺的主要问题。由于受体需求量和标准供体的数量的严重不平衡,外科医生们将目光转移到心脏死亡供体（DCD）。相比于脑死亡供体（DBD）,DCD面临的主要问题是经历更长的热缺血时间（WIT）,以致患者术后并发症发生率增加,尤其是胆道并发症。受控心脏死亡供体（cDCD）是指在符合患者或家属意愿的情况下有计划地退出维持生命的治疗,在一段“无接触”时间后（通常为5 min）,宣布患者大脑循环永久缺失,同时快速进行器官恢复。由于使用常规器官保存方法保存的DCD移植物的移植效果不尽如人意,近年来,常温灌注技术所展现出的优势在移植过程中愈发明显,逐渐引起外科医生和科学家们的关注。与活体肝移植以及DBD肝移植不同,DCD在宣布死亡前无法取出移植物。而在常温局部灌注（NRP）中,外科医生们能够在宣布死亡后阻断流向大脑的血液,并通过体外膜氧合启动器官的热灌注,在供体体内恢复供体肝脏的功能,使肝脏产生胆汁并清除乳酸。这一过程为供体肝脏离开供体和移植前的各项指标监测和优化提供宝贵时间。目前已有多项临床研究表明,NRP作为一种原位器官修复技术能够使cDCD供体肝脏的移植效果与DBD供体相近。另外,一些研究者还开发了多种灌注技术的联合应用,包括NRP与机器灌注（MP）以及双低温氧合机灌注（D-HOPE）的联合使用,均展现出良好的移植效果,为肝移植供体保存提供更多可能性。虽然许多学者认为NRP是一种获取更多高质量器官的保存方法,但有研究者质疑该技术的伦理问题。他们认为该技术违背死亡捐赠规则,NRP灌注程序中所涉及的操作可能导致患者的死亡,因此,确保患者的循环以及呼吸的永久性不可恢复状态以及在NRP期间确保脑部循环的缺失尤其重要。鉴于NRP在移植领域的重要性,笔者对NRP技术在cDCD中的应用进行归纳总结。

Application of normothermic regional perfusion in controlled donation after cardiac death liver transplant donors

Currently, the main challenge faced by the global organ transplantation field is the shortage of donors. Due to a severe imbalance between the demand for recipients and the number of standard donors, surgeons have shifted their focus to donation after cardiac death (DCD). Compared to donation after brain death (DBD), DCD faces the major issue of experiencing a longer warm ischemia time (WIT), leading to an increased rate of postoperative complications in patients, particularly biliary complications. Controlled donation after cardiac death (cDCD) refers to a planned withdrawal of life-sustaining treatments following the wishes of the patients or their families. After a period of "no contact" (usually 5 min), the patient is declared permanently deprived of cerebral circulation while rapid organ recovery is performed. Since the transplantation of DCD donors preserved using conventional organ preservation methods is not satisfactory, the advantages of the normothermic perfusion technique have become increasingly evident during transplantation in recent years, garnering attention from surgeons and scientists. Unlike living liver transplantation and DBD liver transplantation, removing the transplant from a DCD donor is impossible before death is pronounced. However, during normothermic regional perfusion (NRP), surgeons can block blood flow to the brain after death is declared and initiate warm perfusion of the donor organ using extracorporeal membrane oxygenation. It restores the function of the donor liver in the donor body, allowing the liver to produce bile and remove lactate. This process provides valuable time to monitor and optimize the indicators of the donor''s liver before it leaves the donor and is transplanted. Several clinical studies have already demonstrated that using NRP as an in-situ organ repair technique can yield transplantation outcomes for cDCD donor livers comparable to those of DBD donors. Additionally, some researchers have developed various combinations of perfusion techniques, including the use of NRP in conjunction with machine perfusion (MP) and dual hypothermic oxygenated machine perfusion (D-HOPE), all of which have shown promising transplantation results, offering more possibilities for liver transplant donor preservation. While many consider NRP a method of obtaining more high-quality organs, some scholars have raised ethical concerns about this technique. They argue that it violates the rules of donation after death and that the procedures involved in NRP perfusion may lead to the patient''s death. Therefore, ensuring that the patient''s circulation and respiration are irreversibly lost and that brain circulation is absent during NRP is particularly crucial. Given the importance of NRP in the field of transplantation, the authors provide a summary of the application of NRP techniques in cDCD.