BOSTON – It seems counterintuitive, but when management times of potential heart and lung donors stretched beyond 20 hours, successful organ procurement rates at one center actually went up rather than down, investigators reported at the annual meeting of the American Association for the Surgery of Trauma.
Among 42 donors managed for 20 hours or less, only six lungs (7% of possible total) and five hearts (12%) could be procured. In contrast, among 58 donors managed for more than 20 hours, 40 lungs (34%) and 26 hearts (45%) could be procured.
The surprising findings, from a prospective analysis of 100 consecutive organ donors, occurred despite the fact that there were no significant differences in attainment of preprocurement donor-management goals, said Dr. A. Britton Christmas of the department of surgery at the Carolina Medical Center in Charlotte, N.C.
A total of 133 organs, mean 3.2/donor, were obtained from donors managed 20 hours or less, and 243, mean 4.2/donor, from those managed for more than 20 hours (P less than .01). There were a mean of 2.6 organs transplanted for each donor managed 20 hours or less, and 3.7 for each managed for more than 20 (P less than .01).
“The general consensus is that early procurement removes the transplant organ from a hostile environment, but we believe that this study provides evidence to the contrary. Perhaps the reward really is worth the wait,” Dr. Christmas said.
Their original hypothesis was that shorter management times would yield higher organ procurement and transplant rates in general and heart and lung transplants in particular.
The investigators collaborated with the organ procurement organization LifeShare of the Carolinas, which covers 40 hospitals in a 20-county region. The analysis consisted of data on 100 consecutive donors from 2007 through 2008 that included age, ethnicity, blood type, mechanisms of death, management teams, organs procured, organs transplanted, donor type, donor management, reasons for non-use of organs, and donor management goals.
Causes of death were traumatic brain injuries in 44 donors, cerebrovascular accidents or strokes in 38, anoxic brain injury in 13, and other in 5.
The management goals included mean arterial pressure (60-100 mm Hg), central venous pressure (4-10 mm Hg), pH (7.30-7.45), PaO2 (greater than 100 mm Hg), serum sodium (155 mEq/L or less), serum glucose (less than 150 mg/dL), and urine output (0.5-0.3 mL/kg per hour).
Although heart and lung procurement rates were significantly higher for donors managed for longer times, there were no significant differences between the less than 20 hours vs. more than 20 hours in terms of the percentage of kidneys (85% and 91%, respectively) or livers (90% in each group) successfully harvested.
There were also no significant differences between the time groups in any of the preprocurement management goals.
The study was limited by the use of data from a single organ procurement organization, small sample size, and lack of data on the exact time of brain death, Dr. Christmas acknowledged.
The investigators speculated that the longer interval between brain death and organ procurement might permit the improvement of in situ graft function and might promote the procurement of some organs initially deemed unsuitable.
Dr. Carrie Sims, the invited discussant, said that additional data might help to explain why waiting longer than 20 hours was associated with better outcomes.
It would be helpful to know what percentage of donor organs originally deemed unacceptable became acceptable with waiting and whether the waiting period allowed for additional studies such as echocardiograms, cardiac angiograms, or bronchoscopies might have demonstrated suitability of organs, said Dr. Sims from the Trauma Center at Penn in Philadelphia. She also noted that differences in fluid balance between the two groups might explain the better rates with longer management times, since other studies have shown that overhydration of donors compromises lung procurement salvage rates.
The study was internally funded. Dr. Christmas and Dr. Sims disclosed no conflicts of interest.