Delayed Rewarming Thrombocytopenia (DRT): A Temperature-Dependent Platelet Aggregation Disorder

Below 32 °C, the second irreversible stage of platelet aggregation is absent, causing augmentation of the first reversible stage of platelet aggregation and adhesion. During rewarming, de-aggregation occurs; however, in the presence of adequate ADP (adenosine diphosphate), the second stage of aggregation occurs, leading to delayed rewarming thrombocytopenia (DRT). Erythrocytes leak ADP in sufficient amounts by 24 h to cause DRT. This is prevented by rewarming within 24 h. Heparin before hypothermia prevents platelet adhesion, as does alcohol, which also blocks the second phase of aggregation. Aspirin blocks the second phase of aggregation, and platelet infusions, stored without erythrocytes, are an effective therapy. DRT explains rewarming deaths in NCI (neonatal cold injury).