Abstract: A method and apparatus for measuring metabolic rates such as oxygen consumption and carbon dioxide elimination rates of a patient intubated on a ventilator utilize an inspiration sample of gases provided by the ventilator and end-tidal and ambient pressure samples of expiration gases exhaled by the patient which are collected and analyzed to determine concentrations of the gases along with flow rate data to calculate the desired metabolic rates on a breath-by-breath flow weighted average basis. The ambient pressure sample is taken from a point prior to complete mixing of the gases exhaled in adjacent breaths and after the exhalation valve such that the pressure is essentially ambient room air pressure to facilitate accurate sychronization of the flow rate and concentration signals.

Abstract: A medical gas alarm system is provided which includes a sensor unit pneumatically connected to a medical gas supply line and a switch connected to a valve in the supply line for detecting the open condition of the valve. In the event either the sensor detects a high pressure or low pressure condition in the supply line or the switch is activated by closing of the valve, an alarm signal is received by an alarm module and an alarm is activated. The alarm may be visual, audible or both. During normal operations, the alarm module displays both a system on condition and a digital display indicating the pressure in the supply line.

Abstract: The multiple optical fiber event sensor apparatus includes a semi-permeable tubular sleeve, and a plurality of individual optical fiber event sensor modules within the sleeve arranged in an axially staggered relationship. A rounded tip is also provided on the distal end of the sleeve. The device provides for a multiplicity of individual sensors incorporated in a single tubular sleeve which minimizes cross-interference and thrombus formation when used as an intravascular multi-sensor.

Abstract: A respirator especially constructed for flight crews has a harness strap which can be inflated to a somewhat rigid, self-sustaining orientation to permit one-handed placement of the respirator over the wearer's head. Once the respirator is in place, release of a lever for inflating the strap deflates the latter to a orientation sufficient to cause the resilient strap to tightly press a peripheral seal of the respirator mask against nose and mouth areas of the user's face. A comfort adjustment to relieve strap tension permits selective reinflation of the strap to a somewhat smaller value than necessary for initial donning of the harness, and the limited reinflation pressure is sufficient for causing the mask to seal against the face during pressure demand breathing. In instances where pressurized breathing is needed, however, pressure within the strap is automatically released so that the strap presents sufficient bias to hold the mask against the face without oxygen leakage therepast.

Abstract: A flow selector device whose fluid flow is regulated by the rotational setting of a rotor body in a housing; and although the metering passageways have outlets spaced from the axis of the rotor and its manipulating shank, other passageways are provided in the housing, which channel the fluid then to an outlet in and concentric with the rotor and its flow-rate adjustment shank. One of those other passageways is an annular groove formed into the rotor's manipulating shank, leading to a radial passageway in the shank, thus carrying fluid to the shank outlet channel regardless of the rotational setting of the rotor. Another of those other passageways is in the housing; and its provision is facilitated by forming it to open onto an outer face-portion of the housing, then sealing the outer portion of the passageways by a ball member forced into the outer end of the passageway. The rotor is held axially of the rotor by a snap ring, and by a nylon ring between the snap ring and the housing.

Abstract: A method for covalently bonding an analyte sensitive dye compound to an additon-cure silicone is disclosed. The method includes a first step of functionalizing the dye compound to provide a linker arm with an isolated multiple bond. A second step includes hydrosilylating the functionalized dye with polymethylhydrosiloxane. The resulting compound is cross-linked with vinyl-terminated polysiloxane in a third and final step.

Abstract: Cannula apparatus for respiration therapy, having a pair of body members, each having a pair of cannulae for providing a cannula nipple outlet for each of a person's nostrils, the two body members respectively delivering gas to each of the person's nostrils, and monitoring the respiration of each of the person's nostrils. One of the body members is carried inwardly of the other, its cannulae also carried inwardly of those of the other, achieving the patient comfort of only feeling a single cannula in each nostril, yet the gas and monitoring lumens and their outlets are separate for good operativity of respiration and breathing-monitoring. Interchangeability of the body members and their respective tubing is providing by operative equality of areas of the cylindrical and annular passages.

Abstract: A rectilinear motion proportional solenoid assembly includes a cylindrical housing containing an electromagnetic coil having a longitudinal coaxial bore. The housing contains maagnetic material for providing a flux path for the magnetic field produced by the coil. A generally cylindrical magnetic pole piece element is inserted into the bore and a movable armature assembly of magnetic material is supported within the bore for movement along the longitudinal axis of the coil by a pair of thin, flexible suspension springs. One of the springs is located within the bore adjacent to one end of the magnetic pole piece whereat an axial gap between the pole piece and the armature is formed. A second spring is located within the housing within the vicinity of a radial air gap between the armature and the housing.

Abstract: A reliable, pulse-flow supplemental oxygen apparatus for alleviating respiratory ailments is provided which yields substantial savings in oxygen while giving the patient the physiological equivalent of a prescribed continuous stream of oxygen. The apparatus preferably includes a demand oxygen valve operated in a pulse mode by means of electronic control circuitry which, through an appropriate sensor, monitors the patient's breathing efforts and gives a variable "custom tailored" pulse volume of oxygen to the patient during the very initial stages of each inspiration.

Abstract: A reliable, pulse-flow supplemental oxygen apparatus for alleviating respiratory ailments is provided which yields substantial savings in oxygen while giving the patient the physiological equivalent of a prescribed continuous stream of oxygen. The apparatus preferably includes a demand oxygen valve operated in a pulse mode by means of electronic control circuitry which, through an appropriate sensor, monitors the patient's breathing efforts and gives a variable "custom tailored" pulse volume of oxygen to the patient during the very initial stages of each inspiration. Pulse volume variability is based upon a measured parameter characterizing at least a part of one and preferably a plurality of the patient's preceding breaths; advantageously, the elapsed time interval of the patient's three preceding breath cycles is measured to effectively measure breath rate.

Abstract: A pressure regulator, of a type having a spring whose compressive force is a factor of the differential of pressure achieved as to the outlet pressure in comparison to the inlet pressure, and whose adjustment of spring pressure achieves a variation of the pressure differential, with the present concepts providing a screw-type camming feature for easily imposing whatever pre-load is desired on the spring to achieve the desired pressure differential of fluid being dispensed by the regulator. The casing is provided with a window through which a tool may be easily passed to give the rotational torque for this camming effect by which the pressure differential adjustment is achieved; and the camming effect provides axial spring-load adjustment by an easily applied rotational torque to an adjustment plate, or to the abutment plate which provides a relief valve function.

Abstract: The humidifier module for use in a gas humidification unit has a humidification chamber and a water heating chamber separated by a water vapor permeable, liquid water impermeable membrane. Gas inlet and outlet ports are provided in the humidification chamber, a water inlet port is provided for the water heating chamber, a water inlet port is provided for the water heating chamber, and a heat exchange wall is provided on one side of the water heating chamber to receive heat from a heat source in the humidification assembly. The gas humidification assembly has an enclosure adjacent the heat source, for receiving the humidifier module, a water supply source, and a controller of the heater and water supply to the humidifier module. A sensor is provided for monitoring the level of fluid within the humidification chamber, and another sensor is provided for monitoring the level of water within the water heating chamber.

Abstract: A respirator especially constructed for flight crews has a harness strap which can be inflated to a somewhat rigid, self-sustaining orientation to permit one-handed placement of the respirator over the wearer's head. Once the respirator is in place, release of a lever for inflating the strap deflates the latter to an orientation sufficient to cause the resilient strap to tightly press a peripheral seal of the respirator mask against nose and mouth areas of the user's face. A comfort adjustment to relieve strap tension permits selective reinflation of the strap to a somewhat smaller value than necessary for initial donning of the harness, and the limited reinflation pressure is sufficient for causing the mask to seal against the face during pressure demand breathing. In instances where pressurized breathing is needed, however, pressure within the strap is automatically released so that the strap presents sufficient bias to hold the mask against the face without oxygen leakage therepast.

Abstract: A pulse oximeter having a sensor responsive to light transmitted through an area of blood flow which is optically absorbed by hemoglobin for producing a pulsatile waveform indicating the current pulsatile component of blood flow. A process waveform is created for tracking the process of the oximeter during its determination of a maximum and a minimum value of the pulsatile waveform, which is used for calculating the saturation of oxygen.

Abstract: An artificially induced blood pulse used for measuring oxygen saturation in arterial blood is produced by a cuff, wrapped around a body member having an artery upstream from a testing site, when a squeezing pulse is applied by the cuff to the body member.

Abstract: An improved nasal puff assembly is provided which is of particular benefit in the treatment of obstructive sleep apnea and which is characterized by a gas-delivery puff which fits only in the nose of the patient and is therefore of relatively small size and can be comfortably worn. The nasal puff of the invention advantageously includes a plenum chamber having an inlet and a pair of laterally spaced outlets; a pair of soft synthetic resin nares elements or pillows are operatively coupled with the spaced plenum outlets and are designed for ready adjustability so that the effective positions thereof can be altered individually for permitting custom fitting of the nares elements with respect to the nares of different patients. In this way a relatively small number of different sizes of nasal puff can be modified to meet the needs of virtually all patients.

Abstract: A connector means which provides a fluid-tight seal, but with relative rotation of a pair of body members of a hydraulic line or device. Cylindrical extensions on both the body members, which interfit in assembly, have circumferential grooves facing one another and receive ball bearing members in the circumferential chamber provided by the grooves; and the arrangement is such that the bearing members act to block axial withdrawal of the body members from a tight sealing engagement with an O-ring which assures fluid-tightness of the joint even though the body members are relatively rotatable.

Abstract: A reliable, pulse-flow supplemental oxygen apparatus for alleviating respiratory ailments is provided which yields substantial savings in oxygen while giving the patient the physiological equivalent of a prescribed continuous stream of oxygen. The apparatus preferably includes a demand oxygen valve operated in a pulse mode by means of electronic control circuitry which, through an appropriate sensor, monitors the patient's breathing efforts and gives a variable "custom tailored" pulse volume of oxygen to the patient during the very initial stages of each inspiration. Pulse volume variability is based upon a measured parameter characterizing at least a part of one and preferably a plurality of the patient's preceeding breaths; advantageously, the elapsed time interval of the patient's three preceding breath cycles is measured to effectively measure breath rate.

Abstract: An easily manipulable, high mechanical advantage latching-actuator apparatus for high pressure gas cylinders is provided which employs a single, bidirectionally rotatable operating collar for latching, on-off gas valve operation, and delatching, so as to facilitate gas therapy and cylinder replacement by patient users. In preferred forms, the apparatus includes a slotted valve body affixed to a gas cylinder, along with a separate actuating assembly including a rotatable operator and a reciprocable valve actuator; locking tabs are secured to the operator, and a cam mechanism is used to couple the operator and the valve actuator. Rotation of the operator in a latching direction serves to first move the tabs into latching engagement with the body slot, whereupon, after further rotation of the operator in the same direction past an intermediate "off" position, the valve actuator is cammed into an "on" position for opening the valve carried by the body, thus permitting gas flow from the cylinder.