Normothermic Regional Perfusion: An Emerging Organ Recovery Procedure
August 4, 2022
Normothermic regional perfusion (NRP) in organ recovery from donation after circulatory determination of death (DCDD) donors is an emerging procedure in the United States which uses extracorporeal means to perfuse transplantable organs with oxygenated autologous blood. NRP is initiated after death is declared based on cessation of the donor’s circulatory function. NRP has been documented to improve utilization of organs for transplant and improve recipient patient outcomes compared to traditional, “rapid-recovery,” of organs from DCDD donors. Because NRP is an organ donation procedure, it is of tremendous importance for organ procurement organizations (OPOs) to be involved in the review, development, and implementation of NRP into practice.
Two NRP techniques exist: (1) thoracoabdominal NRP (TA-NRP) and (2) abdominal NRP (A-NRP). TA-NRP involves cannulation of the right atrial appendage and ascending aorta for evaluation of the heart for transplantation (abdominal organs benefit from this technique and are usually recovered as well), whereas A-NRP involves perfusion and recovery of abdominal organs (thoracic organs are not perfused but may also be recovered in standard rapid fashion). The distinction between TA-NRP and A-NRP is relevant to specific protocol components that implicate different legal and ethical considerations. Abdominal-only organ recovery can also be done with right atrial appendage and ascending aortic cannulation, and this technique is legally and ethically viewed the same as TA-NRP.
TA-NRP includes occluding the great vessels off the aortic arch to prevent brain reperfusion. Also, exclusive to TA-NRP is the resumption of a beating heart, which allows assessment of its function and suitability for transplantation. This functional assessment is not possible in a rapid-recovery DCDD and has resulted in an increasing number of thoracic organs available for transplantation. AOPO acknowledges there are ongoing discussions regarding ethical considerations accompanying TA-NRP and urges OPOs participate in that discourse.
A-NRP prevents brain reperfusion by occluding the descending thoracic aorta, creating a perfusion circuit that includes only abdominal organs (although the lower extremities can be included). A-NRP has not been subject to the same ethical or legal discussions largely because it involves neither heart perfusion (and the potential for resumption of heart function) nor directly occluding blood flow to the brain.
Neither type of NRP should result in brain reperfusion. Without measures to prevent this, however, brain perfusion could occur through collateral vessels that bypass the site(s) of arterial/aortic occlusion. Accordingly, AOPO’s position is that every surgical team planning to perform NRP in an OPO’s donation service area should provide assurance to the OPO that their surgical protocol explicitly includes effective methods to prevent brain reperfusion.
OPOs should develop guidelines for communicating with potential donor families when NRP may be implemented for the purpose of optimizing organ viability in a particular case. As with all communication with donor families, the goal is transparency, respect, and stewardship, recognizing the appropriate details communicated vary by family and/or situation. AOPO also emphasizes the importance of communication with the donor hospital team to ensure a full understanding of procedure elements, resource needs, and resolution of any questions prior to initiating an NRP procedure during organ recovery.
While NRP is more mature in other countries, it is a relatively new and emerging clinical innovation in organ preservation in the U.S. with wide-ranging impact on multiple stakeholders. AOPO recognizes variation in OPO experience with NRP and jurisdictional differences in legal standards and practices. Consideration of important legal and ethical considerations, as well as the potential transplant benefits of NRP, is paramount for each OPO. Its impact on donors and donor families, waitlisted candidates, and public perception of organ donation requires engagement and collaboration across all stakeholders as the practice of NRP continues to evolve.