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 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.

Abstract: A restrictor fitting is provided at the discharge side of an infusion pump to substantially reduce or eliminate the presence of undissolved gas such as air within the detection field of an air-in-line sensor. The restrictor fitting defines a flow orifice of reduced cross-sectional size disposed along an infusion line in close proximity with a pump discharge port, and at a position slightly downstream from the air-in-line sensor. The restrictor fitting maintains an infusion liquid under substantially constant pressure conditions, with minimal pressure drop across the sensor detection field, and thereby minimizes the occurrence of undissolved gas attributable to outgassing at that location. In addition, the flow orifice acts as a bubble trap to prevent backflow of gas bubbles to the sensor detection field.

Abstract: A non-invasive, fluid monitor engages an open resonator with a segment of fluid line. The fluid line is disposed such that it and the fluid within become a part of the dielectric loading on the resonator. The open resonator is a part of an oscillator circuit that changes frequency of oscillation in response to the dielectric loading on the resonator. A frequency discriminator monitors the frequency of the oscillator to detect an air bubble in the fluid line. In the case where the resonator comprises a microstrip line, the microstrip line is disposed in parallel to the segment of the fluid line and the length of the microstrip line is selected to be equal to or greater than the maximum length of air bubble permitted thus providing a volumetric air-in-line sensor. The output of the frequency discriminator is compared to a threshold to determine a frequency shift large enough to indicate the presence of an air bubble.

Abstract: A pressure waveform monitor for non-invasively monitoring the pressure waveform inside a vessel, such as an artery, includes a flexible diaphragm extended across an opening of a container containing a fluid. The flexible diaphragm is placed against tissue surrounding an artery such that arterial pressure causes a deflection in the diaphragm. A deflection in the diaphragm causes the fluid to be redistributed throughout the container which is effectively divided into an array of volume compartments. The relative volume distribution is determined through impedance plethysmography. The diaphragm is maintained in a calibrated position by maintaining the array of volume compartments at relatively unchanged volumes. When the relative volumes remain essentially unchanged, calibrated tonometry is possible. The pressure within the container is then used to determine the pulse waveform and the pressure within the artery.

Abstract: A fluid shut off valve for use in a parenteral fluid administration set includes a disk floating in a fluid chamber that shuts off fluid flow when the fluid in the chamber decreases below a certain level. The chamber includes a valve stem at its lower end that has both a valve seat and an alignment member with an alignment surface on the top end thereof for guiding the disk into proper seating on the valve seat. The valve seat and floating disk have complementary engagement surfaces for also guiding the disk into proper seating on the valve seat. In one embodiment, the alignment member includes fins located both on the valve stem and on the inside wall of the chamber. Because of the configuration of the alignment member, dislodgement of the disk from the valve seat is made easier.

Abstract: Bidirectional flow patterns are induced in a fluid supply line and the reverse flow resistance and the forward flow resistance are measured and compared. A measure of the resistance to flow is made by normalizing a sum of the entire pressure response about a pressure baseline according to the volume of fluid in the bidirectional flow pattern. In the event that the cannula is positioned near or against the vessel wall, the resulting relatively large negative pressure response can indicate the positional irregularity. In one embodiment, a time period of zero flow is included between the positive and negative flow volumes to permit the system to stabilize.

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: A fluid flow control system having a valve disposed in-line with a fluid conduit extending between a fluid container and a fluid receiver. The conduit and valve are designed to be used with a fluid infusion device such as a peristaltic pump. The valve is non-clamping and includes a rotatable member with an external handle for controlling the valve between flow and flow stop positions. The handle can be manually operated as well as automatically operated. Mounted to the infusion device is an automatic operating mechanism for cooperating with the pumping mechanism of the infusion device to control the position of the valve. In a disclosed embodiment, the operating mechanism is mounted to an access door of the pump which cannot be closed until the peristaltic mechanism is engaged with the tubing. When the door is closed, the operating mechanism automatically moves the valve to the flow position. When the access door is opened, the mechanism automatically moves the valve to the flow stop position.