Evaluation of acid-base status in brain dead donors and the impact of metabolic acidosis on organ retrieval.

Background: Pathophysiologic changes after brain death can lead to acid-base disturbances. The primary aim of this study was to clarify the acid-base state and its source in brain dead donors using Stewart's approach. Additionally, we investigated whether the presence of metabolic acidosis affected the number of organs retrieved from donors. Methods: A retrospective review of electronic medical records was performed for brain dead donors who had undergone organ harvesting during the past 5 years in a tertiary medical center. The parameters related to acidbase disturbance and the number of organs retrieved from the donors was assessed. Results: Sixty one brain dead donors were evaluated in this study. Twenty three (37.7%) of these patients had metabolic acidosis at the initial diagnosis of brain death. Metabolic acidosis resulted from hyperchloremia and a large strong ion gap. The severity of metabolic acidosis was masked by hypernatremia and hypoalbuminemia. In addition, donors without metabolic acidosis also showed mixed acid-base disturbances in which metabolic acidosis induced by significant hyperchloremia was combined with metabolic alkalosis caused by hypoalbuminemia and hypernatremia. Although more organs were retrieved from the donors without metabolic acidosis than those with metabolic acidosis (P=0.012), serum albumin level (P=0.010) and donor age (P<0.001), rather than metabolic acid-base disturbances, significantly correlated with the number of organs retrieved in multivariate regression analysis. Conclusion: Most brain dead donors exhibited metabolic acid-base disturbances. However, rather than metabolic acidosis, serum albumin level and donor age were well correlated with the number of organs retrieved.