Aggressive Donor Care—To What End?

Abstract

D rs DeBose and Salim provide a useful overview of some current accomplishments in organ procurement and offer an algorithm for treatment of hypotension and other clinical problems often encountered during donor care. Although it seems intuitive that proper critical care of the donor would yield the best possible organs for awaiting recipient(s), this part of the transplantation continuum has not received the scientific inquiry it deserves. There is very little evidence-based data to define ‘‘proper care’’ or to guide treatment to the desired goal of delivering optimal organs. Donor organs are often damaged during the evolution of brain death due to the catastrophic physiological mechanisms described in their article. Extensive experimental animal and human observational data confirm important changes in cardiovascular function, fluid and electrolyte balance, endocrine homeostasis, and proinflammatory mediator production, as they have referenced. The resultant organ dysfunction, although at times irreparable, can be reversed by skillful resuscitation, as demonstrated by a series of publications from Papworth Hospital in Cambridge during the 1990s. It is important, however, to consider not only the methods of intervention, as proposed in the protocol offered by DuBose and Salim, but also the treatment end points and the personnel to whom it is entrusted. Many authoritative groups have recommended guidelines for donor care that generally seek only to reestablish or maintain normal physiologic or laboratory values. The purpose of donor care, however, is to support whatever selection and allocation criteria will ultimately best serve the recipient. As such, organ acceptance and distribution are based upon a combination of donor and recipient characteristics. Some donor parameters are fixed, such as age, gender, medical/surgical/social history, cause of death, body size, and so on and cannot be altered during donor treatment. Others, however, such as cardiac contractility, vascular resistance, oxygenation, serum electrolyte concentrations, interstitial edema, and so on are amenable to therapy. Correcting the abnormalities is these latter criteria, as discussed by DeBose and Salim, may allow organs previously rejected to be transplanted and function normally. Criteria for organ acceptance, however, are often affected by the subjectivity of the transplant team and/or availability of donors at the time of a recipient’s urgent need. Acceptance criteria may then be ‘‘extended’’ so as to expand the general availability of organs or to rescue individual recipients. The extent to which individual criteria can be expanded while still yielding acceptable organs remains a major question in the procurement process. Similarly, how such ranges of physiological and fixed variables interrelate is unknown. For example, might a young male donor after trauma tolerate a lower mean arterial pressure, higher serum sodium, or greater anemia during donor care than an older woman who died because of an intracerebral hemorrhage, yet still yield organs of acceptable quality? An approach to such questions has been introduced by the Donor Risk Index which interrelates fixed variables, but how fixed variables relate to those that can be treated, how ‘‘treatable’’ variables interrelate and how donor and recipient variables can be matched remain unknown. Development of a risk-weighted assessment of individual and combined variables could be developed through a properly designed and powered research inquiry and remains an important challenge for the procurement community. From the Departments of Neurosurgery and Internal Medicine, The University of Texas Health Science Center at Houston Medical School, Houston, Texas.