Abstract: An electronic method and apparatus for automatically determining systolic and diastolic blood pressures and heart rate by accurately detecting, verifying and evaluating the full stream of korotkoff sounds produced as electrical signals from a microphone in a cuff occluding the brachial artery of a patient and the corresponding blood pressure pulse signals which accompany and are precursors to genuine korotkoff sound signals. Blood pressure is measured with the aid of a programmed data processor such as a microprocessor.

Abstract: A fluid infusion system includes a selector valve for convenient interruption of administration of a primary infusion fluid to a patient to permit administration of a secondary infusion fluid, such as a selected drug solution, followed by resumption of primary fluid flow. The selector valve includes a valve housing with a primary spike for connection to a primary fluid container, a dual path secondary spike for connection to a vial or the like containing the secondary infusion fluid, and an outlet fitting for connection to the patient, for example, through a standard intravenous (IV) infusion set. A valve insert is movably mounted within the valve housing and defines a fluid channel network for controlling flow from the primary and secondary spikes to the outlet fitting.

Abstract: A patient infusion and blood chemistry monitoring system is provided for controlled fluid infusion with intermittent interruption for automated drawing of a patient blood sample into contact with one or more electrochemical sensors to obtain blood chemistry determinations, such as measurements of blood electrolytes and the like. The system comprises an infusion pump operated by a control unit to supply a selected fluid to the patient through an infusion line and catheter. The control unit intermittently halts and reverses operation of the infusion pump to draw a patient blood sample through the catheter into contact with the electrochemical sensors positioned along the infusion line within a compact cassette near the patient and then to reinfuse the blood sample into the patient upon resumption of normal infusion operation. The sensors provide electrical input signals representative of patient blood chemistry to an analyzer which alters the signals to an appropriate readable output.

Abstract: The invention relates to a peristaltic pump wherein a plurality of cam actuated fingers are adapted to pump fluid through a flexible tube by sequentially closing off the fluid filled tube along a length thereof. The fingers are mounted to rotate on a common axis and are spaced from one another in order to reduce the power requirement for operating the pump. A rigid, spring loaded pressure pad, preferably mounted on the same axis as the cam actuated fingers, maintains essentially the same pressure on each of the fingers as they close off the adjacent portion of the tube.

Abstract: Apparatus and related method for use in a parenteral administration system, for detecting fault conditions such as an infiltration, an open fluid line or an air bubble in the fluid line. The apparatus is particularly adapted for use with a parenteral administration system of the type that includes a pulsing infusion device for incrementally infusing fluid through a fluid tube to a patient's venous or arterial system. The apparatus qualitatively evaluates the pressure in the fluid tube to detect characteristic patterns indicative of each such fault condition and actuates an alarm whenever one is detected.

Abstract: A disposable syringe cartridge including a molded plastic cylinder having an open end and a closed end with inlet and outlet nipples integrally formed in the closed end, and a plastic piston head slidably received in the open end of the cylinder and pivotably connected to a plastic piston rod. The piston head utilizes a quad-type sealing ring providing a pair of adjacent sealing surfaces with the cylinder, and includes a square expansion flange rounded at each of its corners to conform in shape to the cylinder, with a rubber annular sealing boot extending between the open end of the syringe cylinder and the piston rod. A flange formed on the outer circumferential edge of the sealing boot is received over the open end of the cylinder and is captured by an annular cap that is ultrasonically welded to the cylinder, while a bead formed on the inner circumferential edge of the sealing boot is received in a groove defined by a pair of adjacent annular flanges formed on the piston rod.

Abstract: A combination load and latch mechanism for fluid flow control apparatus, wherein a latch mounted for pivotal movement may be manually opened to disengage an electromechanical manipulating device to permit loading or unloading a feeding tube, the latch automatically closing and the device re-engaging upon release of the latch. The latch includes a slotted side wall that defines a retaining surface for capturing the tube relative to the manipulating device, and a cam surface upon which the tube acts during loading to cam the latch open. Means are included for sensing movement of the latch prior to any disengagement of the manipulating device.

Abstract: Method and apparatus for detecting occlusions in a parenteral administration system of a type having a peristaltic pump for pumping a fluid through a feeding tube to a patient. A pressure transducer measures the cyclicly varying pressure of the fluid in the feeding tube and produces a corresponding pressure signal, and a comparator compares the pressure signal to a selected one of several thresholds, depending on the current stage of the pumping cycle. An occlusion alarm is actuated whenever the selected threshold is exceeded.

Abstract: A mechanism for screw drive and syringe plunger engagement and disengagement for a syringe infusion pump, wherein a split-nut pair are moveable into and out of engagement with a lead screw by means of rotary cam control, the rotary cam being keyed with a crank disk that is coupled to a crank arm, which operates as the syringe plunger mover. The crank arm is rotatable into and out of engagement with the syringe plunger, such rotation also causing the split-nut pair to move into and out of engagement with the lead screw. Index and cam means are carried by the crank arm to aid in proper alignment with the syringe plunger, and a sensor is provided for monitoring proper engagement of the crank arm with the plunger.

Abstract: A pressure detector for particular use in a system for administering parenteral fluid to a human patient. The pressure detector includes a conventional pressure diaphragm having a flexible membrane that is movable in accordance with the pressure of the fluid being administered. The pressure detector further includes a special receptacle for retaining the pressure diaphragm, and a special follower assembly that is moved in a prescribed fashion by installation of the diaphragm in the receptacle and by movement of the diaphragm membrane due to variations in fluid pressure. A pair of electrical contacts are controllably moved together and apart by the follower assembly, to provide an electrical signal whenever the diaphragm is not installed or, if it is installed, whenever the fluid pressure exceeds a prescribed threshold.

Abstract: A pressure diaphragm, wherein at least a portion of an elongate fluid channel is formed diametrically across, and is open through, a flat raised surface of a substantially rigid, disk-like body, and wherein a flexible membrane overlies the raised surface and is sealed to a surrounding flange. The fluid channel communicates with fluid inlet and outlet fittings carried by the body, which are adapted for connection with the tubes of an IV set, and the cross-sectional flow area of the fluid channel is substantially equal to or less than the cross-sectional flow area of any IV tube adapted for connection to the fluid inlet fitting.

Abstract: A drop sensing unit and associated, disposable drip chamber for dedicated use with the sensing unit in an IV fluid administration system, the sensing unit being adapted for convenient installation on and removal from the drip chamber, with cooperable engaging means on the sensing unit and chamber serving to locate and retain them in the desired relative position during use. Such engaging means provide for contact between the sensing unit and chamber at vertically spaced locations for effective retention, and are constructed and arranged to aid in preventing use of the sensing unit on drip chambers which differ from the specially designed chamber.