In medical applications, fluid must sometimes be conveyed intravenously to a patient undergoing treatment. The fluid is usually contained in a fluid reservoir, typically a bag, conveyed through a tube, and injected into the patient's vein. Many times, regulating the volume and rate of fluid conveyed to the patient is advantageous, and in such instances, traditionally, infusion pumps are employed.
One such infusion pump effective for the application described above is disclosed in U.S. Pat. No. 4,559,038 ("the '038 patent") the entirety of which is herein incorporated by reference. The infusion pump disclosed and described therein regulates the conveyance of fluid from a fluid reservoir to a patient. In accordance with the infusion pump of the '038 patent, a fluid reservoir containing fluid for treating a patient is held in a cassette having a pressure plate immediately adjacent to a pump control module. A tube for conveying the fluid couples the fluid reservoir and the patient and provides a medium for conveying the fluid. A pump control module regulates the rate fluid is conveyed to the patient by applying physical pressure to the tube, thereby restricting the volume of fluid flow. In the '038 patent, the pump control module further comprises a pumping mechanism, having tube engaging members which engage and squeeze the tube against the pressure plate of the cassette. The tube engaging members include an expulser and an inlet valve and an outlet valve on opposite sides of the expulser.
A variation of the infusion pump described in the '038 patent includes a pump control module substantially as described above used in conjunction with a remote fluid reservoir, i.e., a fluid reservoir separate from the pump control module and the cassette. Typically, in infusion pumps incorporating remote fluid reservoirs, the fluid is still contained in the fluid reservoir, however, the fluid reservoir is secured on a holding apparatus, such as a pole, separate from the pump control module instead of in the cassette. The tube conveying the fluid from the remote fluid reservoir to the patient typically extends from the fluid reservoir, across the pump control module, and, to the patient.
In the past, due primarily to safety and hygiene concerns, cassettes were permanently attached to the tube, and when the fluid reservoir emptied or the patient's treatment was completed, the fluid reservoir, the tube, and the cassette were all discarded. Of course, disposing of the cassette contributes to waste and expense; therefore, reusable systems and methods which assist the operator replacing the fluid reservoir and expedite handling procedures associated with the system are desirable. The need for reusable cassettes and associated infusion pumps exists.