Frost anesthesia, obtained by freezing the skin with a jet of the volatile liquid, dichlorotetrafluoroethane,1 (Freon 114), has proved useful for cutting split skin grafts,2,3 circumventing the need for general anesthesia or voluminous injections of a local anesthetic agent.
Unfortunately, small canisters of dichlorotetrafluoroethane have proved inconvenient for skin grafts because the contents are so quickly exhausted. Large industrial cylinders with a delivery hose and simple nozzle are difficult to manage because of bubble formation and sputtering of the Freon spray. Bubble formation is caused by the in114. The delivery tube and nozzle are cooled as Freon evaporates through the vent of the precooling chamber.
Frost anesthesia with Freon 114 does not affect the viability of skin grafts and will not damage the donor sites if the freezing time in any one area is less than one minute.
First the valve on the tank of Freon 114