Medical infusion pump with sensors

Claim 1

A medical infusion pump for receiving fluid through an administration set inlet tube and discharging fluid through an administration set delivery tube, comprising: (a) a housing, the housing including (1) means defining a generally circular first cutout area having first wall means defining a first profile including a plurality of spaced apart teeth projecting inwardly therefrom, (2) means defining a second cutout area adjacent said first cutout area, having second wall means defining a second profile, (b) a pump assembly mounted in said housing and including (1) a wheel having a peripheral surface, said wheel being mounted within said first cutout area, (2) administration set tubing comprising an inlet tube, a delivery tube and a tube segment interposed between said wheel and said first wall means, said segment fluidly connected to said inlet tube and said delivery tube, (3) means for selectively moving the wheel to a first position wherein a portion of said peripheral surface of the wheel compresses a portion of said tube segment against at least one of said teeth in said first wall means, and a second position wherein the wheel is spaced from said first wall means sufficiently to permit removal and replacement of the tube segment from between the wheel and said first wall means, (4) means for rotating the wheel eccentrically within the first wall means when the wheel is in the first position, such that said tube segment receives fluid from the inlet tube and the fluid is pumped through the tube segment by a peristaltic type action into the delivery tube; (c) a bubble sensor assembly mounted on said housing for measuring changes in the air bubble content of the fluid in one of said inlet or delivery tubes, including (1) a pair of sensor blocks defining a generally V-shaped trough for cradling the sides of said tube, (2) an ultrasonic transducer in each of the blocks, oriented substantially parallel thereto toward the sides of the tubes, and (3) means for applying a slight pressure on the upper surface of the tubing along the portion thereof above the trough, whereby the portions of the tubing in contact with the blocks are held in substantially flat contact therewith during operation of the ultrasonic transducer; (d) a pressure sensor assembly including (1) a first cassette removably located in said second cutout and including a fluid chamber in fluid communication with one of said tubes and a cassette disphragm responsive to the pressure in said chamber; and (2) a Hall effect sensor assembly including a movable magnet mounted in said housing and means in contact with said cassette diaphragm for translating movement of the cassette diaphragm into movements of said magnet commensurate with the pressure in said fluid chamber; and (e) a flow control assembly including a second cassette removably located in said second cutout area and means for providing fluid communication with at least one of said tubes and said first cassette, said second cassette including, (1) a body portion, (2) a flow chamber including an orifice in said body portion, (3) a valve movable within the flow chamber to change the flow area of the orifice, and (4) a thumb wheel mounted on the body portion and engaging the valve for controlling the flow area of the orifice.