Thermal Burns From Plaster Splints

January 1, 2002
John F. Connolly, MD
John F. Connolly, MD

Plaster of Paris itself can be hazardous because of the thermal reactions thatoccur as the material sets. When water is added to plaster of Paris powder, thewater molecules go from a liquid to a solid state by incorporating into the crystallattice of the calcium sulfate hemihydrate. This converts kinetic energy intoheat. If hot water is applied to plaster of Paris to begin this kinetic process, theheat given off from the resulting crystallization can actually burn the patient'slimb.

Plaster of Paris itself can be hazardous because of the thermal reactions thatoccur as the material sets. When water is added to plaster of Paris powder, thewater molecules go from a liquid to a solid state by incorporating into the crystallattice of the calcium sulfate hemihydrate. This converts kinetic energy intoheat. If hot water is applied to plaster of Paris to begin this kinetic process, theheat given off from the resulting crystallization can actually burn the patient'slimb.Such was the case in this patient, who sustained a third-degree burn tothe back of his calf after his limb was splinted with plaster made with hotwater. The combination of the hot water and the heat from the plaster's crystallizationresulted in this soft tissue injury, which required several plasticsurgery procedures for coverage.When applying a plaster of Paris splint or cast, be sure to keep the waterat room temperature or at a temperature that allows you to immerse yourungloved hand without any discomfort.