Abstract: A pumping mechanism moving in movement increments is controlled to space those movement increments in direct proportion to the volume resulting from each movement increment. In a further aspect, movement increments are grouped to result in approximately equal volumes per group. The mechanism moves continuously through the movement increments in each group. Groups are spaced to result in approximately equal flow volumes per group. The number of groups decreases as the flow rate increases. The number of movement increments in each group and the volume of each group increase as the flow rate increases.

Abstract: An IV pump for delivering fluid through a resilient, deformable tube to improve the accuracy, consistency, and predictability of flow through the tube, wherein a plurality of pinching fingers occlude the tube against a flat portion of a pressure pad, and a plurality of pumping fingers interspaced between said pinching fingers deform the tube (without occluding it) from different directions against a V-shaped portion of the pressure pad to pump the fluid downstream as well as to urge the tube to restore its cross-sectional area.

Abstract: A valve mechanism for a needleless connector employs a deformable piston having a piston head of elliptical cross-section with a marquise-shaped bore formed along its longitudinal axis wherein the major axes of the respective generally elliptical shapes are oriented perpendicular to one another. The piston head is captured within the connector housing and is reciprocal between a section of reduced diameter adjacent the connection port and a section of enlarged diameter. Constraining the piston head into the section of reduced diameter causes the elliptical bore to be squeezed shut while positioning the piston head in the section of enlarged diameter causes the piston head to relax and assume its natural elliptical shape, while the bore similarly regains its natural open shape to provide a fluid path therethrough. A compressible or extendible section affixed to the piston head serves to bias the piston into the section of reduced diameter.

Abstract: A device for mounting a tonometry sensor upon a patient's wrist includes a base portion that is specifically adapted to generally conform to the patient's wrist while providing a stable placement of the tonometry sensor relative to a preselected artery. A sensor housing is movably mounted upon the base portion and configured such that the mounting device has an essentially equal thickness at each end of the device. A strap member is provided for releasably securing the mounting device to a patient's wrist. The mounting device facilitates more accurate, non-invasive blood pressure measurement by providing a stable placement of the tonometry sensor relative to the tissue overlying a preselected artery at a measurement location and, further, limits undesirable movement by the patient to thereby reduce undesirable error in the blood pressure measurement.

Abstract: An infusion system with an air-in-line sensor is provided with improved apparatus and method for quickly and easily clearing small quantities of undissolved gas such as air from the sensor detection field. The infusion system includes an infusion pump having control components responsive to the air-in-line sensor to activate an alarm and/or to cease pump operation when undissolved gas is detected. A "clear air" key or switch is provided on the pump for actuation by medical personnel to operate the pump in a manner delivering a small pulse of the infusion liquid to move a small detected quantity of gas past the air-in-line sensor. The system can be adapted for actuation of the "clear air" key up to a selected number of times, while monitoring and accumulating the total fluid quantity delivered to a patient.

Abstract: Impedance to fluid flow in a fluid delivery line is measured. Two techniques are used depending on the flow rate selected. For high flow rates, the pump is controlled to vary the flow rate and the change in pressure is divided by the change in flow to directly determine the resistance. For low flow rates, a processor controls the pump to pump flow quantities in accordance with a pseudo-random binary code. The resulting pressure signal sensed at the conduit is decoded in accordance with that code. Pressures received during code periods of no flow are subtracted from pressures received during code periods of flow. Pressure offset is also removed and a least squares estimation approach is used with a linear prediction model to determine impedance. The coefficients determined in the model are used to calculate the resistance to fluid flow of the system. A quality supervisor monitors the resistance determination process and controls the display of resistance depending on the quality determined.

Abstract: An interlock, latching and retaining mechanism for use in an infusion system, embodying a latch arm mounted to a rotatable shaft having a plurality of cams and gears attached thereto, a rectangular faceplate with a plurality of apertures formed therethrough, and a clamp. Rotating the latch arm functions to engage fluid monitoring, flow control and pumping structure of the infusion system with a pumping segment for control of fluid flow through the segment and also causes the clamp to hold the pumping segment in a required position. In another aspect, rotation of the latch arm additionally causes an air-in-line sensor to rotate into position on the pumping segment.

Abstract: An engineered pumping segment for facilitating efficient and accurate peristaltic pumping of fluids, providing regulation of fluid flow and providing an effective interface for sensing fluid line pressure in a peristaltic pump system. The engineered pumping segment includes an elastomeric membrane sandwiched between a rigid base and a rigid cover and a slider adapted to slidably mount about the base and cover. The membrane and base define a channel for fluid flow and the membrane, base and cover cooperate to facilitate peristaltic pumping of fluids through the engineered pumping segment and to provide a pressure sensing interface, and in combination with the slider, cooperate to regulate fluid flow.

Abstract: A sliding flow controller for controlling flow through a pumping segment used in a fluid delivery system. The flow controller includes a slider that travels along a channel defined by an elastomeric membrane and a variable size groove formed in a rigid component. The slider includes a projecting ball that presses the membrane against the groove. At one end the groove has a maximum cross-sectional area for a maximum flow position and at another end, the groove has no cross-sectional area for a flow stop position. The slider and the pumping segment have respective click stops to impart sensory feedback to the operator when manually operated. A ramped thumb indentation is provided on the exterior of the slider to facilitate sliding movement.

Abstract: An IV fluid delivery system for use with a resilient, deformable tube, wherein a mechanism is provided to restore the cross-sectional shape of the tube after it has been deformed by a plurality of pinchers, so as to improve the accuracy, consistency, reliability and predictability of flow through the tube.

Abstract: A needleless connector allowing infusion and withdrawal of fluid in medical applications is disclosed. The injection site has a housing which contains a blunt cannula within it. An elastomeric pre-slit plunger is movably carried within the housing by the housing and said blunt cannula. Insertion of a connector moves the elastomeric pre-slit plunger from a first, occluding position deeper into the housing and over the blunt cannula to a second position, where the pre-slit portion of the plunger is penetrated by the blunt cannula. This opens a fluid passage from the inserted connector through the cannula to the opposite end of the housing, allowing fluid flow through the connector. Pressurized gas within the housing, or an elastically deformable member, or the two in combination, bias the elastomeric plunger back to its first position. As an inserted connector is removed, the fluid pathway through the injection site is re-sealed.

Abstract: A plunger driver system which engages a plurality of different sizes of syringes. A pushing surface includes a detector to determine syringe plunger presence. In the event that the plunger is not present and the pump is operating, a processor provides an alarm and may stop the pump motor. Arms retain the plunger flange in a fixed position in relation to the plunger driver. The arms have anti-siphon flanges to prevent too rapid movement of the plunger into the syringe barrel. A shelf for opposing downward movement of the syringe plunger and a ramp to guide the syringe plunger into position in relation to the plunger driver are included in the plunger driver. A cradle for containing all sizes of syringe barrels yet aligning the syringes with the plunger driver is included with a clamp to hold the syringe barrel in position in the cradle. The detector button includes a bevel at its top edge to facilitate loading the plunger in the driver.

Abstract: A fluid delivery system in which the pressure platen for a fluid conduit is fixedly mounted to the pump and the pumping mechanism is movable in relation to the platen to control the force exerted on the conduit. A mounting system comprising a four-bar linkage retains the movable pumping mechanism in a predetermined orientation to the conduit through the mechanism's range of movement. The pumping mechanism is spring loaded towards the conduit. The peristaltic fingers of the pump mechanism are located in guides with the drive means for those fingers rigidly mounted to that guide. Should the movements of one or more fingers through the respective guide be prevented, the drive means will be stopped from movement and the pumping mechanism will stall rather than back off and allow free flow.

Abstract: An air-in-line sensing apparatus for use with a parenteral fluid administration set to detect the passage of air through a fluid conduit. The apparatus comprises a first housing having a first arcuate section mounting a first transducer adjacent the first arcuate section and a second housing having a second arcuate section mounting a second transducer adjacent the second arcuate section. One housing is independently movable relative to the other housing so that when the movable housing is moved towards the other housing, the first and second arcuate sections capture a length of administration set tubing therebetween providing secure intimate contact therewith. A signal may be generated from one of such transducers, passed through the fluid conduit and received by the other transducer to detect whether the conduit is carrying air.

Abstract: A drive member of a peristaltic pumping mechanism includes a disk that rotates with the drive member and has two transparent sectors and two opaque sectors alternating with the transparent sectors. As a stepper motor rotates the drive member to pump fluid, a single optical sensor senses the disk and provides signals indicative of whether a transparent sector or opaque sector is being detected. A processor counts the number of motor steps in the detected transparent or opaque sector and based on the number of counted steps in a type of sector detected or the number of steps counted when a state change to the other type of sector occurs, determines the motor position. In another aspect, the position disk is integrally formed as a single piece with the cams and cam shaft of a pumping mechanism.

Abstract: An IV pump for delivering fluid through a resilient, deformable tube to improve the accuracy, consistency, and predictability of flow through the tube, wherein a plurality of pinching fingers occlude the tube against a flat portion of a pressure pad, and a plurality of pumping fingers interspaced between said pinching fingers deform the tube (without occluding it) from different directions against a V-shaped portion of the pressure pad to pump the fluid downstream as well as to urge the tube to restore its cross-sectional area.

Abstract: An IV fluid delivery system for use in connection with a resilient, deformable tube, wherein pinching fingers occlude the tube and pumping fingers deform the tube (without occluding it) against a first pressure pad or support means in a pumping action, while restoring fingers urge the tube against a second pressure pad or support means to restore its cross-sectional shape, so as to improve the accuracy, consistency, and predictability of flow through the tube.