Organ donation after cardiac determination of death (DCD): a swine model.

Donors after Cardiac Death (DCD) may reduce the organ scarcity; however, their use is limited because of warm ischemia time. Fortunately, this is less important in a subclass of DCD called expected (e-DCD), those with irreversible but incomplete brain injury. This study analyzed hemodynamic/pulmonary data to establish a clinically relevant model of cardiac death that would simulate an e-DCD setting. Hemodynamics, pulmonary artery flows, arterial blood gasses, and left atrial pressure were recorded q 5 minutes in anesthetized swine. After baseline data collection, the ventilator was discontinued and heparin was administered. Cardiac death was defined: as asystole, or mean arterial presusure < or = 25 mm Hg with a pulse pressure < or = 20 mm Hg. The time to death was approximately 14.8 minutes. Within 5 minutes of removal of the ventilator, there was a hyperdynamic period. Blood gases throughout the apneic time showed a rapid hypercapnia and acidosis. The hyperdynamic reflex response was followed by hypotension, bradycardia, and finally asystole or ventricular fibrillation. The protocol of withdrawal of ventilation, systemic anticoagulation, determination of death was developed to closely resemble the clinical e-DCD scenario. The physiologic changes that happen before death in DCD were described. An e-DCD model that can be used in studies related to organ transplantation was established.