Abstract: A needle valve including a deformable seal positioned between the distal end of the needle and a hard, mechanical seat between the needle and the valve housing. The deformable seal is able to seal around the movable needle but is protected from serious deformation by the hard mechanical seat that is located so as to prevent the needle from entering the deformable seat beyond a predetermined amount. Thus the deformable seal does not extrude due to the entrance of the needle and wear is reduced.

Abstract: A calibration boot for use with an optical catheter includes a plurality of materials, each having a different reflectivity characteristic with respect to known wavelengths of light. The boot is positioned over the distal end of the optical catheter and light is emitted from the distal end of the optical catheter into one of the materials at a time. At each emission, the reflected or backscattered light is measured by a detector and a plurality of signals are obtained. The plurality of readings are used to calibrate the overall optical catheter and system. The use of a plurality of calibration signals improves the overall system accuracy, particularly where two or more variables are present in the measured parameter. In the preferred system, the parameter being sensed in the oxygenatin of blood invasively.

Abstract: A rotary type of flowmeter having an orifice directing the flow toward a moveable needle. The needle moves within a channel that has a varying cross-sectional area in a plane transverse to the needle movement such that the effect of the velocity of the fluid impinging on the needle to cause its movement is controlled.

Abstract: A circuit for monitoring the program flow of a computerized or microprocessed system, includes a comparator for matching a uniquely assigned address for entering a given mode of operation, with an address presented by the system controller for entering the operating mode. If the addresses do not match, in response to the detected illegal mode entry attempt, a reset signal is generated for resetting the controller to reinitiate the programmed flow of operation.

Abstract: A system for controlling the amount of light radiation directed upon an infant from a fiberoptic phototherapy pad by feedback from a light detector that itself is a fiberoptic pad. The fiberoptic detecting pad receives and detects the light density radiation over an area and is located intermediate the normal fiberoptic phototherapy pad and the infant and therefore is in the best position to detect accurately, the light impinging upon the infant. In some embodiments, the light detector pad is manufactured as part of the fiberoptic phototherapy pad itself as a unitary construction. Light readily travels through the light detector to the infant, yet the light detector senses the light intensity and density of the light passing therethrough.

Abstract: The nasal septum probe of the present invention mounts the optical devices of a photoplethysmographic probe in a housing that clips onto the patient's nasal septum. The septum provides an arterial bed for monitoring purposes and this locus is not subject to significant patient motion or peripheral shutdown of arteriolar blood flow. Furthermore, one embodiment of the invention shows a combination of the photoplethysmographic apparatus with a nasal cannula to provide dual purpose apparatus to minimize the sensor and cable proliferation.

Abstract: A needle valve having improved economy of manufacture and assembly is disclosed in which the tapered end of the needle moves axially with respect to a valve seat having a cylindrical opening but does not rotate. An adjusting means, in turn, is rotated to cause the axial movement of the needle and an alignment means, preferably a sphere, is interposed between the needle and the adjusting means to provide alignment between the two components. The needle itself is also spring biased away from the valve seat.

Abstract: A medical ventilator is provided which continuously controls both inspiratory and expiratory flow and pressure, including positive end expiratory pressure (PEEP), through control of a single inspiratory flow-control valve. This valve controls inspiratory flow and pressure and, during expiration, controls expiratory flow and pressure by controlling the pressure within the back chamber of an expiratory diaphragm or balloon-type valve. Feedback signals preferably are provided to the valve's controller to provide inspiratory closed-loop flow control and continuous inspiratory and expiratory closed-loop pressure control.

Abstract: A luminescence based analytical probe is excited with light varying repetitively in amplitude at multiple modulation frequencies. A composite signal incorporating components at a plurality of these modulation frequencies, produced by emissions in all of the various decaying modes is analyzed to provide information, such as the fractional luminescence contribution and/or lifetime of each individual decaying mode because the various decaying mode are segregated by analysis of the composite signal, there is no need to segregate light from the various decaying mode according to the wavelength of the light. Therefore, the probe may incorporate plural luminescent materials which have different decay modes with different luminescent decay times and sensitive to different conditions to be monitored, even if the plural luminescent materials absorb and emit light at the same wavelengths.

Abstract: A medical ventilator is provided for providing continuous, closed-loop control of the pressure of gas within a patient's mouth or respiratory tract in accordance with any selected pressure input waveform. The medical ventilator comprises an adaptive, feedback controller which provides independent control of the inspiratory and expiratory branches of the ventilator, while continuously controlling mouth pressure. The digital coefficients of the controller are updated to adjust for variations in the resistance of the patient's respiratory tract resulting from the magnitude of flow of inspiratory gas into the tract and patient-to-patient differences. Pressure in the expiratory branch is controlled by controlling, through a pressure-regulating valve, the magnitude of back pressure applied to a diaphragm valve. A venturi provides a reference pressure for the pressure-regulating valve below that of the surrounding atmosphere to enable application of a negative back pressure to the diaphragm valve.

Abstract: This arterial blood monitoring system takes advantage of the basic statistical property that arterial blood contains a plurality of dominant absorbers, whose measured light absorption spectra appear as a constant over a short interval of time. By measuring the transmitted light as it varies with arterial pulsation at selected wavelengths of light, over a common light path, the relative amount of these dominant absorbers in the arterial blood can noninvasively be determined. To ensure the common light path, a sandwich construction light detector is used.

Abstract: Apparatus and method for metering the flow rate of a fluid through a conduit in which a low inertia transducer is placed between the inlet and outlet, the transducer having a substantially cylindrical housing and a rotatable element concentric to the housing which together define an arcuate pathway for the flow of the fluid. A pressure sensor generates a pressure error signal corresponding to a change in pressure between the inlet and outlet and translates the same into a detectable signal which is used to change the speed of the rotatable element to reduce the differential pressure between the inlet and outlet.

Abstract: A combination of a protective tube and guidewire straightener used to locate a guidewire into a patient for introducing a catheter into a patient's bloodvessel. The guidewire straightener has a flexible end that flexes inwardly to lock the guidewire in a fixed position within the protective tube. The protective tube has an opening so that the guidewire straightener can be rotated by the user to align the flexible end with the opening to allow the flexible end to be released outwardly to unlock the guidewire so that it can move within the protective tube. A further opening in the shape of an elongated slot is formed in the protective tube and which allows the user to move the guidewire to advance or retract the guidewire from the protective tube. The positioning of the components are such that a user, by the manipulation of only one hand, can unlock the guidewire from it's fixed position and advance it into the patient, leaving the user's other hand free to carry out other operations.

Abstract: A flow control valve is disclosed wherein a deformable elastomeric element is positioned at least partially within the flow path of a fluid passing between an inlet and an outlet. By deforming the elastomeric element, the cross-section of the flow path of the fluid is changed, thereby controlling the flow of fluid through the flow control valve. The elastomeric element may be of various standard configurations and is easy and inexpensive to replace in the event of excessive wear.

Abstract: A magneto-pneumatic timing device is disclosed that provides a pressure signal alternating between a high and a low pressure output signal. The duty cycle may be varied as well as the overall cycle time. A magnetically biased flexible diaphragm divides a chamber into a pair of subchambers and the differential pressure between the subchambers is controlled to cause the flexible diaphragm to pull away from the magnetic bias to one position and to return to its biased position. Control of the output pressure signal is carried out by varying the resistance in certain of the pneumatic passages that are part of the control function for the differential pressure. The device is relatively simple and inexpensive to construct and features very few moving parts, thus it is reliable and capable of high production, low cost manufacture.

Abstract: An intermittent suction device for removing fluids from a patient where the duty cycle between the OFF and ON cycles is controlled by a magnetically susceptible diaphragm that switches back and forth between first and second positions, representing ON and OFF positions, by controlling the differential pressure across the diaphragm. The diaphragm is biased toward it first position by a permanent magnet that acts to attract the flexible diaphragm. The device has few moving parts and its duty cycle and overall cycle times are easily adjusted by the user.

Abstract: A rotary type flowmeter having a variable orifice through which the flow to be measured is directed toward a rotatable needle. A preload is also applied and which may be varied as desired. By the use of the variable orifice and with the preload, the same flowmeter may be used for differing ranges of flow by minor adjustment and various indicating scales may be taylored to the particular flow being monitored.

Abstract: The universal pulse oximeter probe [of the present invention] utilizes an inexpensive sensor connector configuration to enable the cable section of the probe to be used numerous times. The [sensor connector is mechanically simple and electrically reliable to interconnect the sensor elements with the cable that connects the pulse oximeter system to the sensor elements. This sensor connector enables the user to obtain significant benefits due to the fact that the expensive cable segment of the probe is a separable element from the housing that contains the sensor elements. In particular, the] cable segment of the probe consists of a connector that is compatible with the pulse oximeter system and which functions to interconnect the pulse oximeter system with a plurality of conductors, the far end of which are terminated in the sensor connector [of the present invention].

Abstract: A gas analysis cell having a pressure control system eliminates pressure variations in the gas cell regardless of changes in restriction, gas viscosity and barometric pressure. Since optical alignment through the gas cell is sensitive to gas pressure, maintaining a constant pressure in the gas cell makes the system more stable.

Abstract: Described herein is a patient interfacing system for sampling the inspired and expired gases of a patient and removing moisture from the sample. In one embodiment of the present invention, a patient link receives the gases from the patient's airway circuit and a vaporization section vaporizes condensed moisture in the sample. A separator section allows the vaporized moisture component of the sample to exit the patient interfacing system before the gas sample reaches the monitoring instrument. A filter may also be utilized to prevent condensed moisture, particulates and liquids from entering the monitoring instrument. Thus, the patient interfacing system of the present invention provides a reliable, cost effective and efficient means for delivering gas samples to a monitoring instrument which reduces or prevents water condensation inside the gas analysis portion of the monitoring instrument.