An Examination of Organ Donor Hemodynamic Variation and Warm Ischemic Times Stratified by Functional Thresholds

OBJECTIVES: During organ donation after death determination by circulatory criteria (DCC), It is thought that graft oxygenation becomes impacted under certain thresholds of blood pressure or oxygen. Prolongation of functional donor warm ischemic time (fdWIT) is a risk for complications, but threshold criteria for when to initiate fdWIT vary. We aimed to assess hemodynamic and potential ischemic variation of fdWIT in patients undergoing withdrawal of life support measures. DESIGN: This was a planned post hoc analysis of clinical and biomarker data collected from patients enrolled in a prospective cohort study of the physiology of death after circulatory arrest. PATIENTS: Patients undergoing withdrawal of life support measures were eligible for recruitment. SETTING: ICU. INTERVENTIONS: Detailed physiologic and biomarker assessment, and a mathematical method termed the DCC Ischemic Index (DII) to quantify hemodynamic variation. MEASUREMENTS AND MAIN RESULTS: We demonstrate that following withdrawal, oxygen saturation (Spo2) and blood pressure thresholds for fdWIT are met sequentially in a predictable manner; thresholds using Spo2 criteria were met first, followed by those using blood pressure criteria. We demonstrate that DII methodology can capture hemodynamic fluctuations, potentially providing an improved method to quantify ischemic graft injury. Lastly, we demonstrate that release of inflammatory cytokines may be more correlated with measures of DII as opposed to fdWIT. CONCLUSIONS: Our findings suggest fdWIT criteria may not be equivalent, and that fdWITs alone may not sufficiently reflect physiologic processes that could lead to graft injury.