Patent ID: 7351226

Claim:
An infusion pump for delivering intravenous solution from a solution bag through tubing to a patient, the bag having at least one flexible wall and having a dispensing port for releasable connection with an end of the tubing, comprising: a housing with a compartment for removably receiving and supporting the intravenous solution bag in a solution-dispensing position, an expandable bladder mounted within the compartment and forming a part of the infusion pump, having a flexible wall which moves by expansion responsive to an increase in the pressure of a fluid within the bladder, the bladder being positioned in the housing so as to apply a pushing force against the flexible wall of a solution bag when present, to collapse the solution bag responsive to expansion of the bladder wall to cause solution within the bag to be infused out through the dispensing port, a sensor for sensing pressure in a solution bag when present, an electric pump connected to pump fluid into the bladder to increase pressure in the bladder in response to an electrical signal indicating the need for increased pressure, a gas cartridge containing high-pressure gas connected to the housing, with a pressure regulator connected to the gas cartridge to produce gas at greatly reduced pressure, said reduced-pressure gas being selectively connected to the bladder, and control means connected to the sensor and effective to send said electrical signal to send fluid to the bladder to increase pressure in the bladder when the sensor indicates pressure in the bladder is below a desired pressure preselected in the control means.