Abstract: An electro-optical connector having a plug containing a center light emitter or detector and an interconnected pair of light detectors or emitters symmetrically positioned with respect to the center light emitter or detector. A socket, also containing a center light detector or emitter and an interconnected pair of symmetrically positioned outer light emitters or detectors, is adapted to receive the plug. The plug may thus be inserted into the socket with a plurality of angular orientations. The plug is retained in the socket by a pair of resilient tabs extending into respective recesses in the socket. The tabs may be removed from the recesses by exerting an outward force on the tabs, either directly or by exerting a transverse force on the plug thereby generating a rotational moment on the plug that exerts an outwardly directed force on the tab. As a result, the plug may be removed from the socket by exerting side forces on the plug without damaging the plug or socket.

Abstract: A method and apparatus for determining the mean arterial pressure in an automatic blood pressure measuring system in which a table of data is obtained of cuff pressures and the amplitude of oscillometric pulses produced at each cuff pressure. The oscillometric pulses having the greatest amplitude and a reference cuff pressure at which such oscillometric pulses occurred are first identified from the table. Respective first and second cuff pressures that are above and below the reference cuff pressure and have a amplitude of 90% of the largest oscillometric pulses are then calculated by interpolating between the measured data in the table, and the mean arterial pressure is then calculated as the average of the first and second cuff pressures.

Abstract: An optical data link for transferring data between a pair of connectors and for activating an electrical device to which one of the connectors is attached. A light-emitting diode (LED) and a phototransistor are mounted in each of the connectors, with the LED of each connector visible to the phototransistor of the other connector when the connectors engage each other. The LEDs and phototransistors are connected to respective interface circuits. The interface circuits for at least one of the LEDs limits the current through the LED regardless of the amplitude of a driving signal. The interface circuits for the phototransistors maintain a relatively constant voltage across the phototransistors so that the phototransistors function as current switches. The electrical device is activated in response to closure of a magnetically sensitive reed switch mounted in the connector attached to the electrical device.

Abstract: A blood pressure cuff having an internal acoustic pickup cup. In one embodiment, the cup communicates with the interior of the blood pressure cuff bladder through an aperture that is sufficiently large to allow pressure equalization between the interior of the bladder and the cup and sufficiently small to prevent Karotkoff sounds from being coupled from the cup to the interior of the bladder. A single pneumatic tube extends from the cup and through the wall of the bladder to a first enclosure that is coupled to a second enclosure through a conduit. The first enclosure contains a microphone for converting the acoustic signals picked up by the cup into a corresponding electrical signal. The second enclosure contains a pressure transducer for providing an electrical signal indicative of the pressure in the bladder. In a second embodiment, the cup and bladder are isolated from each other and separate tubes extend from the bladder and the cup to separate enclosures.

Abstract: A tubular airway adapter having a hollow interior and a cylindrical wall for providing a sample gas air flow. The adapter includes an annular channel in the cylindrical wall and a plurality of radial channels extending from the annular channel to the interior. The annular channel is in fluid communication with ambient atmosphere through a port in the cylindrical wall. The wall of the adapter increases in thickness from on either side of the annular channel towards the annular channel to provide a double conically shaped interior and a wall region which protrudes into the interior at the location of the annular channel.

Abstract: A harness is provided for holding a blood pressure cuff in the correct position on the arm when being worn for extended periods of time. The harness has a support member that attaches by clasps directly to the cuff on the person's arm. The support member extends from the cuff to the shoulder region of the user so that the weight of the cuff is carried by the shoulder rather than by the arm through contact pressure from the cuff itself. The support member prevents slippage or rotation of the cuff throughout the monitoring period. A strap is provided that attaches to the support member at the shoulder region and runs under the other arm of the user to hold the support member in the correct position.

Abstract: A self-adjusting blood pressure cuff assembly. A cinch ring at the fixed end of the blood pressure cuff assembly has at least one lateral extension disposed away from the direction of the fixed end of the flexible belt of the cuff assembly. The longitudinal extension has two longitudinally directed sides. Placing reinforcing stitches closely adjacent the longitudinally directed sides substantially restricts transverse movements of the cinch ring with respect to the flexible band. In a preferred embodiment, a tag piece, passing through the slot of the cinch ring and covering the lateral extension, is reinforced stitched to the outward cover of the elongated flexible band of the blood pressure cuff assembly. In this way, an end of an inflatable bladder can be caused to be adjacent to the loop of material forming the fixed end of the flexible band.

Abstract: A method and system for patient monitoring wherein data acquired by parameter measuring modules is downloaded to an information processing and display station. Table data structures resident within the modules are downloaded to the display station during initialization of the module on the link. The tables completely define the number, functionality and visual attributes of all control keys associated with each channel of the module. The tables include: text and parse tables which define the number, size, attributes and text for each key; a process table which contains a plurality of control programs which are executed by an interpreter portion of the display software in response to activations of a control key; and a channel control table which modifies the operating conditions of the channel in response to preselected control keys.

Abstract: A method and apparatus for the indirect measurement of blood pressure is disclosed. Pressure is applied to a cuff attached to a patient adjacent a blood vessel and a quantity representative of the patient's blood pressure is measured as the applied pressure is changed. A table of values of the quantity as the applied pressure is changed is formed. Valves of the table are selected as spurious high and low values in response to predetermined criteria and new values assigned to the selected values which reduces the error in calculating systolic and diastolic blood pressure from the table.

Abstract: A method and apparatus for smoothing raw oscillometric table data in the region around systolic blood pressure to reduce respiration interference is disclosed. Systolic blood pressure is determined by averaging intermediate systolic pressures calculated in association with dual thresholds instead of a single threshold. Interpolation is used between adjacent applied cuff pressure values having table entries located on either side of each of the upper and lower threshold values. Normalization of the table is employed to improve interpolation resolution.

Abstract: A method and apparatus for the indirect measurement of blood pressure is disclosed. Pressure is applied to a cuff attached to a patient adjacent a blood vessel and a quantity representative of the patient's blood pressure is measured as the applied pressure is changed. A first table of values of the quantity as the applied pressure is changed is formed. Values of the first table are selected as spurious high and low values in response to predetermined criteria and new values assigned to the selected values which reduces the error in calculating systolic and diastolic blood pressures from the table. A second table of heart rate values as the applied pressure is changed is formed. Selected heart rate values are set to zero based on predetermined criteria and the locations of the zeros are compared with the locations of systolic, diastolic and maximum values in first table to determine whether to reject or abort the blood pressure reading.

Abstract: An apparatus for servicing a removable RAM package of an ambulatory medical monitor is disclosed. The RAM package comprises a RAM for storing blood pressure data and operating parameters and a real time timer. Both are coupled to a multipin edge connector by parallel multibit data and address buses. An adapter for servicing the RAM package by a scanner controller through a standard serial interface is provided. The adapter comprises a microcomputer chip coupled between an RS-232 serial interface and a multipin edge connector for mating engagement with the edge connector on the RAM package. Servicing includes writing and reading data from the RAM package, and reading and setting the time in the real time timer. The apparatus further includes means for controlling access to the adapter by the scanner controller using an identification and unlocking scheme. The system will not unlock if a RAM package is not coupled to the adapter.

Abstract: A blood pressure cuff particularly for use with ambulatory blood pressure products and suitable for use in either the left or right limbs of the patient is disclosed. The cuff includes an elongated, flexible band having a body side face and an outward face and a compartment. It further includes an inflatable bladder having a centerline and adapted for placement within the compartment in either a first position or a second position rotated 180.degree. from the first position. The bladder includes a portion coupled on one side of the centerline and adapted to protrude through an opening in the band when the bladder is in either the first or second position. The opening comprises two separate openings on either side of the centerline. First and second indicia placed adjacent the openings on the outward face of the band identify the position of the protruding portion for use on either the left or right side limb.

Abstract: A self applied blood pressure cuff particularly for use with ambulatory blood pressure products and suitable for use on either the left or right limbs of the patient is disclosed. The cuff includes an elongated, flexible band having a body side face and an outward face and a compartment. It further includes an inflatable bladder having a portion adapted to protrude through one of two openings in the band when the bladder is on either the left or right arm. The two openings are located opposite one another on opposite lengthwise edges of the band. First and second indicia placed adjacent the openings on the outward face of the band identify the position of the protruding portion for use on either the left or right arm.

Abstract: A blood pressure cuff particularly for use with ambulatory blood pressure products and suitable for use on either the left or right limbs of the patient is disclosed. The cuff includes an elongated, flexible band having a body side face and an outward face and a compartment. It further includes an inflatable bladder having a centerline and adapted for placement within the compartment in either a first position or a second position rotated 180.degree. from the first position. The bladder includes a portion coupled on one side of the centerline and adapted to protrude through an opening in the band when the bladder is in either the first or second position. The opening comprises two separate openings on either side of the centerline. First and second indicia placed adjacent the openings on the outward face of the band identify the position of the protruding portion for use on either the left or right side limb.

Abstract: A water trap for use in a capnographic sampling line is disclosed. It includes a main body, a liquid collection chamber in communication with ambient atmosphere through a first channel, a cylindrically shaped separation chamber which communicates at a first end with ambient atmosphere through the top of the main body and at its end opposite the first end with the collection chamber, and a sampling gas input channel in communication with ambient atmosphere and which extends into the separation chamber tangentially to the interior wall thereof.

Abstract: An apparatus and method for monitoring the expansion and contraction of the thoracic cavity during respiration is disclosed. A constant current carrier is passed through the thorax of a patient using a pair of ECG leads. The resulting amplitude modulated voltage signal is synchronously detected using a reference signal which is phase-locked to the amplitude modulated voltage signal. A phase locked loop (PLL) having a tri-state phase comparator and a voltage controlled oscillator (VCO) is used to generate the reference signal. A dead zone compensation circuit is coupled to the VCO to provide a trickle current that causes the tri-state phase comparator to be biased out of its null state.