Page 1594 - Hall et al (2015) Principles of Critical Care-McGraw-Hill

CHAPTER 116: Care of the Multiorgan Donor 1113

these previously considered marginal donors, or more appropriately from cerebrovascular accident, and cold ischemic time. To date, many
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termed “extended” donors are now being used, any potential brain-dead donor organs that were previously not considered suitable for trans-
patient without obvious contraindication to organ donation should be plantation, “marginal” or extended grafts are now being used in selected
referred to appropriate local organ procurement agencies for final deter- circumstances. The extended donors are identified based on demo-
mination of suitability. graphic, clinical, laboratory, and histologic data. This includes donor age
■ RENAL EVALUATION >70 years or <3 months, donor body weight over 100 kg, moderate or
severe macrovesicular fat infiltration of the liver, and abnormal liver func-
The discard rate of kidneys procured from cadaveric donors in the tion tests. Serum aspartate aminotransferase (AST) >160 IU/L, serum
United States has been increasing to an alarming level of more than 15% sodium >160 mmol/L, donor stay in intensive care of more than 5 days,
of kidneys recovered for transplantation. Approximately 50% of kidneys significant periods of hypotension (<60 mm Hg systolic BP for more than
from cadaveric donors over 60 years of age (older-age donors) are not 30 minutes associated with a rise in serum AST), and significant systemic
transplanted due to donor quality. infection are all parameters considered to define extended grafts.
The renal system in a cadaveric donor undergoes a number of physi- Donor selection remains highly subjective, and in the absence of reliable
ologic changes that are influenced dramatically by both the medical laboratory tests the decision whether to use an extended graft is left to the
therapies used to prevent brain death and by brain death itself. Timely judgment of the transplant surgeon. The definition of what constitutes
hemodynamic management is important because the risk of acute tubular an “extended” graft will continue to vary between centers until reliable
necrosis and allograft failure could increase if donor systolic blood pres- parameters are available for prospectively predicting early graft function. 54
sure is consistently lower than 80 to 90 mm Hg. The results of basic renal
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function tests such as measurement of serum levels of creatinine and urea DONOR MANAGEMENT
nitrogen and urinalysis should be reviewed to provide a profile of renal
system function in the donor since admission. When kidney donors are Specific donor management may only begin after the diagnosis of brain
evaluated, the effect of hemoconcentration on the results of these studies death has been determined. Brain death is a catastrophic event associ-
should always be considered. Elevated levels of serum creatinine and urea ated with significant disturbances to many organ systems (Table 116-6).
nitrogen and atypical urinalysis findings may suggest that renal function
was compromised. The relative risk of dialysis after transplantation is TABLE 116-6 Physiologic Changes Associated With Brain Death
1.5 times greater in recipients of kidneys from donors >55 years of Neurologic
age versus those who are <55. Table 116-5 shows the latest approved
expanded kidney donor criteria, based on the relative risk >1.7 of having Increased intracranial pressure, herniation
a graft failure for donors older than 50 years of age with at least two of Cardiopulmonary
the following factors: creatinine >1.5 mg/dL, a cerebrovascular accident Hypertension followed by hypotension
(CVA) as a cause of death, and hypertension, as compared to a reference Tachycardia
group of nonhypertensive donors between the ages of 10 and 39 whose
cause of death was not CVA, and whose creatinine was <1.5 mg/dL. Bradycardia
■ LIVER EVALUATION Arrhythmias (premature ventricular beats, asystole)
Myocardial dysfunction
The assessment of a donor liver before transplantation has been the sub- Myocardial ischemia
ject of much research; however, clinically one still relies on a subjective
interpretation of donor data and the macro- and microscopic appearance Increased pulmonary artery pressures
of the liver to decide whether to use the graft. More reliable predictors Pulmonary edema
of graft function are required. Significant efforts have been made to try Cardiac arrest
to assess donor grafts by evaluating different aspects of liver function, Endocrine and Metabolic a
including the ability of the liver to synthesize proteins, metabolize drugs,
secrete bile, produce high-energy phosphates, and by following the levels Decreased aerobic metabolism
of markers of microvascular injury. Feng et al have identified donor Increased anaerobic metabolism
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factors predicting posttransplant graft failure: donor age, height, dona- Decreased circulating pituitary hormones
tion after cardiac death, split liver donor, black race, donor cause of death Diabetes insipidus
Electrolyte disturbances
TABLE 116-5 Marginal Cadaver Kidney Donors
Hypernatremia
Donor Age Categories Hypokalemia
Donor Condition <10 10-39 40-49 50-59 ≥60 Hypomagnesemia
CVA + HTN + Creat >1.5 • • Hypocalcemia
CVA + HTN • • Hypophosphatemia
CVA + Creat >1.5 • • Hyperglycemia
HTN + Creat >1.5 • • Hematologic
CVA • Coagulopathy
HTN • Disseminated intravascular coagulation
Creatinine >1.5 • Factor and platelet dilution
None of the above • Other
Creat >1.5, creatinine >1.5 mg/dL; CVA, cerebrovascular accident; HTN, history of hypertension; •, Hyperthermia followed by hypothermia
marginal donors. a Other than antidiuretic hormone, the exact hormones that become deficient is controversial.
Reproduced with permission from Rosengard BR, Feng S, Alfrey EJ, et al. Report of the Crystal City meeting to Reproduced with permission from Tuttle-Newhall JE, Collins BH, Kuo PC, et al. Organ donation and
maximize the use of organs recovered from the cadaver donor. Am J Transplant. September 2002;2(8):701-711. treatment of the multiorgan donor. Curr Probl Surg. May 2003;40(5):266-310.

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