Thermal damage to red cells.

Erythrocytes from a burned patient show a temporal sequence of morphological changes. Immediate severe changes occur which are followed by a transient phase only of less abnormal morphology. Heating whole blood in vitro to 49 degrees C instead of 50 degrees C does not show the expected dose response curve. Heating whole blood in vitro to 50 degrees C induces progressive morphological changes. Fractionation of whole blood and subsequent heating to 48 degrees C show the older cells to be less deformable.