Abstract: A medical connector assembly comprises a connector body having a fluid passage there through, a valve member, and means, responsive to a compressive force placed on the medical connector, for permitting a fluid to freely communicate between openings in the connector body. The valve member can be constructed using a single element having a slit therein or it can be constructed using two separate halves which when joined together form an interface slit. In a preferred embodiment, when a compressive force is exerted against the connector body, sufficient distortion is experienced by the valve member to open the slit and permit fluid flow between connector body openings.

Abstract: A calibration apparatus for use in calibrating a tissue stress sensor used in a blood pressure monitoring system. The calibration apparatus includes a calibration head which is adapted to be retained in close proximity to a tissue stress sensor. The calibration head includes means for heating the tissue stress sensor. A calibration system is also disclosed for calibrating a blood pressure monitoring system, the blood pressure monitoring system employing a stress sensor for generating an electric output signal representative of tissue stress data. The calibration system comprises a tissue stress sensor having a displaceable diaphragm and a sealed chamber. The chamber has a continuous wall defining an inner volume and an outer volume. The displaceable diaphragm comprises a portion of the continuous wall, whereby the displaceable diaphragm is responsive to a pressure differential between the inner chamber volume and the outer chamber volume.

Abstract: An air-in-line sensor is provided comprising an adapter for insertion in the fluid line and a sensor housing. The adapter is semi-compliant and includes convex-shaped acoustic coupling surfaces for engaging the straight and rigid transducer sensing walls of the housing. The convex surfaces of the adapter have a larger diameter than the distance between the housing sensing walls and an interference fit results. Due to this interference fit, the shape of the coupling surfaces, the varying thicknesses of the adapter walls and the difference in compliance of the materials of the adapter and the housing, a more uniform contact pressure profile is provided. The upper part of each sensing channel wall in the housing includes a ledge which wipes contaminants from the coupling surfaces of the adapter as it is inserted into the sensor channel of the housing.

Abstract: A tissue contact stress sensing system incorporates a semiconductor assembly and a continuous diaphragm to noninvasively determine the intra-arterial blood pressure of a patient. The system comprises a continuous diaphragm placed against a patient's tissue which covers an underlying artery. The semiconductor assembly is placed in close proximity to and spaced apart from the diaphragm for directly irradiating the diaphragm with electromagnetic radiation and receiving a portion of the electromagnetic radiation which is reflected from the continuous diaphragm. The disclosed system also utilizes a technique for minimizing the system errors associated with temperature drift and aging of the sensor.

Abstract: An infrared detector receives infrared energy from the target and provides a detector signal based primarily on the difference between the infrared detector temperature and the temperature of the reference temperature area of the detector. A contact temperature measurement device provides a reference signal which is a function of the temperature of the reference temperature area of the detector. A processor receives the detector and reference signals and combines the two signals in a non-linear manner to result in a signal which is representative of the temperature of the target. The method of non-linearly combining includes the use of gain and offset terms which may be altered to a limited extent by a technician in the field with a blackbody calibration source. As a result of the recalibration, accurate target temperature measurements are continually provided.

Abstract: A sensor system has a two-housing arrangement, each housing of which contains a transducer. One housing includes the transmitter transducer and a flat engaging surface for pressing against the fluid line and deforming it. The other housing includes the receiver transducer mounted so that it is coupled to the bottom of a rectangular U-shaped channel for receiving the fluid line. A spring biases the flat surface of the first housing into contact with the fluid line and deforms the fluid line into the shape of the channel so that the fluid line fills the channel. The channel is shaped to force the fluid line into a general rectangular shape as it is pressed into the channel by the flat surface. Two walls of the deformed fluid line are oriented in a direction perpendicular to the flat engaging surface of the first housing and provide an opposing force to the flat surface.

Abstract: Automatic engagement of a lead screw with a lead screw drive mechanism. A plunger driver used to move the plunger of a syringe is connected to the screw drive mechanism. A first detector provides a plunger signal indicating the presence of a syringe plunger in the plunger driver and a second detector provides a thread engagement signal indicating engagement or disengagement of the lead screw drive mechanism with the lead screw. The thread engagement detector monitors movement of a rigid linkage at the screw drive mechanism which has a nonlinear characteristic curve. In the case where the plunger signal indicates the presence of a plunger and the thread engagement signal indicates engagement of the drive mechanism with the lead screw, the lead screw is rotated in a forward direction to remove the thread clearance.

Abstract: A half-nut block containing a threaded bore and a larger, overlapping, unthreaded bore is engaged with a lead screw. The larger bore overlaps the threaded bore so that effectively a half-nut results. The half-nut comprises a face having an acute angle in relation to the lead screw and this angled face contacts the inside of a bearing block within which the half-nut is mounted. The bearing block is slidably mounted on a C-tube which is mounted around and extends along a predetermined length of the lead screw. Also mounted on the C-tube is an arm for transmitting the linear motion of the bearing block to a remote point such as the plunger of a syringe. The arm is coupled to the bearing block at points selected so that transmission to the arm of any wobbling of the bearing block is reduced. The arm includes a lever which engages a cam formed on the half-nut to force the half nut to disengage from the lead screw when the arm is to be moved to a new location on the lead screw.

Abstract: An apparatus and method for detecting pressure and occlusion in a fluid line is for use with a fluid line being operated upon by a positive displacement, peristaltic pump having several cam follower fingers pressing against the fluid line fluid through the line peristaltically. A sensor follower finger is mounted to the cam shaft of the pump among the other peristaltic fingers in order to cyclicly press against the fluid line and displace the fluid line by a predetermined amount as the cam shaft rotates. The sensor follower finger includes a strain gauge mounted on the sensor finger to generate a signal indicating the degree of force being applied by the sensor finger against the tubing, and a signal processor which receives this force signal and determines the pressure within the fluid line based upon the signal. The signal processor determines the existence of an occlusion based on the signal and provides an alarm if an occlusion is determined.

Abstract: A storage chamber large enough to store a predetermined number of probe covers is formed into a dispenser body. A spring biases the probe covers toward one end of the chamber at which is located a slide. The slide has an indentation used to retrieve a single probe cover from the chamber at a time when aligned with the chamber. Located in the indentation is an aperture tube for receiving a probe of the instrument to be covered. The probe is pressed into the probe cover and into the aperture thus causing the probe cover to stretch and cover the probe. A flange formed on the slide is pressed by a user to align the indentation of the slide with the chamber. The slide is spring loaded so that releasing the flange will result in the slide moving such that the identation is located outside the chamber and the retrieved probe cover can be applied to the instrument. A door in the dispenser is raised to allow access to the chamber for the insertion of a stack of probe covers.

Abstract: The method and system for detecting occlusion in a fluid line upstream of a pump concerns a fluid pump with a pump cycle in which the upstream pressure of the fluid line is communicated to the downstream portion of the fluid line. A pressure sensor located downstream of the pump is capable of measuring a relatively large negative-going pressure in the fluid line. A signal is generated to indicate occlusion based upon detection of negative-going pressure.

Abstract: The system and method for detecting abnormalities in infusion of parenteral fluid involves producing perturbation of fluid flow by varying the flow rate of the fluid with respect to an equilibrium flow rate, measuring the pressure level, and measuring the pressure of the fluid over a period of time, to determine equilibrium pressure and a pressure response of the fluid to the perturbation, determining an integral of the difference between the equilibrium pressure and the pressure response, determining resistance to fluid flow, determining a second integral of the difference between the pressure response and equilibrium pressure multiplied by time, and determining compliance by dividing the second integral by the first integral. Resistance and compliance values are displayed, and an alarm is generated when the resistance or compliance parameters fall outside of reference ranges.

Abstract: The protective apparatus for a biomedical thermometer having a protruding probe containing a waveguide includes mounting a transparent window at the patient end of the waveguide to seal the waveguide from contamination while permitting infrared energy to pass. A protective sleeve protects and mounts the transparent window to the waveguide and material is provided along the entire probe-length of the waveguide to protect it. An outer boot is mounted over the transparent window and waveguide protection material to provide further protection and to supply a mounting and retaining surface for a protective probe cover. A disposable protective probe cover having a generally thin, flat, frame member with an aperture therethrough, is sized to fit over and be retained over the base of the probe by a friction interference fit.

Abstract: A disposable cone channel insertion probe is adapted for use in combination with an infrared thermometer. The probe has a generally frusto-conical hollow body portion, an inner reflective surface, and a flange projecting radially outward from the rearward end of the probe. The infrared thermometer also includes a mechanism for retaining the probe and optics for further focusing and collimating the infrared light from the probe to an infrared sensor.