A blood pressure-regulating device for inducing hemorrhagic shock.

An instrument for producing closely controlled and repeatable hemorrhagic shock in laboratory animals is described. A Sarns roller pump, controlled by an electronic device, is used to pump blood in and out of the animal at a constant rate. Photoelectric cells are used to sense pressure changes and depending on their configuration, the pump runs forward or backward or stops. Pressures are accurately maintained, bleeding and reinfusion rates are controlled, and a record of bleeding patterns is provided.