Timing of heparin and perfusion temperature during procurement of organs with extracorporeal support in donors after circulatory determination of death.
ABSTRACT Despite successful resuscitation of donors after circulatory determination of death (DCD) with extracorporeal support (ECS), the technique is limited by ethical concerns about donor management (heparinization) and the complexity to operate the ECS circuit. This work studies different timing of heparin administration and the effects of ECS-perfusion temperature. Cardiac arrest (CA) was induced in swine. Heparin studies, three groups: 1) PRE5, heparin 5 minutes before CA; 2) POST5, heparin 5 minutes after CA, plus 2 minutes external chest compressions; and 3) POST30, heparin with the initiation of ECS after 30 minutes CA. Perfusion temperature study, two groups: 1) normothermic, ECS-38.5°C after 30 minutes CA and 2) room temperature, ECS-25.5°C for the first 90 minutes, followed by ECS-38.5°C. Heparin studies: ECS target flows (>50 ml/kg/min) were not achieved in the POST30 group, affecting local organ perfusion as observed with poor bile (<4 ml/min) and urine output (<25 ml/min), when compared with the other groups (normal values). Temperature study: In both groups, ECS target flows were reached, and urine/bile output was restored. Heparinization 5 minutes after CA is equivalent to premortem heparinization in this ECS-DCD model. Heparinization after CA could reduce ethical concerns. Donors after circulatory determination of death were successfully resuscitated at both temperatures, suggesting that the heat exchanger/water heater can be removed to simplify the ECS circuit.