Abstract: A flexible sensor with strain relief on electrical contacts. Wires are attached to the electrical contacts, then a bulge of material is deposited over them, such as an adhesive. The wires are then bent back over the top of the bulge and secured. This prevents any tugging on the cable from pulling directly on the attachment of the wires to the contacts.

Abstract: A method and apparatus for reducing the effects of noise on a system for measuring physiological parameters, such as, for example, a pulse oximeter. The method and apparatus of the invention take into account the physical limitations on various physiological parameters being monitored when weighting and averaging a series of measurements. Varying weights are assigned different measurements, measurements are rejected, and the averaging period is adjusted according to the reliability of the measurements. Similarly, calculated values derived from analyzing the measurements are also assigned varying weights and averaged over adjustable periods. More specifically, a general class of filters such as, for example, Kalman filters, is employed in processing the measurements and calculated values. The filters use mathematical models which describe how the physiological parameters change in time, and how these parameters relate to measurement in a noisy environment.

Abstract: An oximeter probe segment with a first fiber optic for carrying light to a patient, and a second fiber optic for carrying return light from the patient. The light is of a wavelength spectrum which can be shifted by travelling through the first and second fiber optics. The probe segment includes an element which is configured to provide a signal corresponding to the shift of the wavelength spectrum through the first and second fiber optics. This signal can either be used to actually measure the shift, or the signal can itself be a coded value corresponding to the shift.

Abstract: A carbon dioxide indicator in an exhaust port of a resuscitator assembly. The carbon dioxide indicator is preferably in a removable insert for ease of maintenance and replacement. Breath-to-breath indications are provided by either exposing the indicator to the ambient air at the exhaust port, or diverting a portion of the fresh air or gases provided to the patient.

Abstract: An airway adapter comprising a tubular portion having opposing windows in a predetermined spaced configuration. The windows have at least one surface which interacts with moisture condensed thereon from respiratory gases so as to reduce the interference of such condensation with the measurement of constituent gases by a gas analyzer. The surface of the windows can be hydrophobic, hydrophilic, or a combination thereof.

Abstract: The present invention provides an encoding mechanism for a medical sensor which uses a modulated signal to provide the coded data to a remote analyzer. The modulated signal could be, for instance, a pulse width modulated signal or a frequency modulated signal. This signal is amplitude independent and thus provides a significant amount of noise immunity.

Abstract: An adapter which actively connects a 2-lead oximeter probe or monitor to a 3-lead monitor or probe. This is done actively, with the alternating drive signals from the oximeter monitor providing a control signal for switching the adapter connections. The adapter connections are preferably made with diodes, transistors, or other active devices.

Abstract: A non-invasive optical sensor which uses the motion signal to calculate the physiological characteristic being measured. For pulse oximetry, a least squares or a ratio-of-ratios technique can be applied to the motion signal itself. This is made possible by selecting a site on the patient where variations in motion produce signals of two wavelengths which are sufficiently correlated. In particular, it has been determined that a sensor placed on a nail, in particular a thumbnail, exhibits the characteristics of having the red and infrared signals correlated when used for pulse oximetry, and the resulting signals correlate to arterial oxygen saturation.

Abstract: An improved method for bending an oximeter sensor which simplifies the manufacturing. The sensor is manufactured without a bend, but when it is packaged for shipping, it is bent and restrained in the bent position. The sensor is made of a material which has memory so that when the packaging which restrains it is removed for use, the sensor will retain a partially bent shape.

Abstract: The present invention provides a medical sensor for detecting a blood characteristic. The sensor includes a transducer for producing an analog signal related to the blood characteristic. The analog signal is converted into a transmission signal which is in amplitude-independent form for transmission to a remote analyzer. In one embodiment, a current-to-frequency converter converts a signal from a pulse oximeter sensor into a frequency signal which can be transmitted over a transmission line to a remote pulse oximeter.

Abstract: A method and apparatus for conserving power in a medical diagnostic apparatus by using a sleep mode during a monitoring state. The sleep mode allows not only the processor to be put to sleep, but other detection circuitry as well. This is accomplished by not relying on detecting events to awaken the sleeping circuitry, but rather establishing the stability of a physiological parameter before going to sleep. The invention monitors a physiological parameter of the patient and enters a sleep mode only after it has been stable for a predetermined period of time. The apparatus is periodically awakened from the sleep mode to take additional measurements and to ascertain that the stability of the physiological parameter has not changed. In one embodiment, the sleep period is chosen to be consistent with the period in which an alarm condition would need to be generated if a patient's condition started to quickly change.

Abstract: An oximeter sensor with an emitter and a detector, and a sensor body surface having a first color proximate to at least one of the emitter or detector. The color can be modified by a user to adapt the sensor to be optimized for maximal signal strength or insensitivity to skin pigmentation variability or accuracy. In a preferred embodiment, a pulse oximeter sensor with an outer layer which is colored gray or black in the region of the emitters and detector and in between can be peeled-away to reveal a substantially white layer. Alternately, a white colored layer could peeled-away to reveal a gray or black layer. Alternately, more than one peeled-away layer could be used to provide a range of colors.

Abstract: The invention is directed to a ventilation control system for controlling the ventilation of a patient. The ventilation control system utilizes a user-friendly user interface for the display of patient data and ventilator status, as well as for entering values for ventilation settings to be used to control the ventilator.

Abstract: The invention is directed to a ventilation control system for controlling the ventilation of a patient. The ventilation control system utilizes a user-friendly user interface for the display of patient data and ventilator status, as well as for entering values for ventilation settings to be used to control the ventilator. Values for ventilation settings entered during set up of the ventilator result in the display of only those further ventilation settings that are appropriate in accordance with the earlier entered settings.

Abstract: An oximeter sensor with an expandable element for positioning the sensor against the fetus. The expandable element is positioned to be removed from at least one of the emitter and detector so that the portion of the sensor adjacent the emitter or detector is not pressed unduly by the expandable element to exsanguinate the tissue. A constant pressure differential between a pressure of the expandable element and an amniotic pressure may be maintained.

Abstract: The present invention relates to a method and apparatus for improving the durability of a sensor, specifically one attached by an adhesive material to a subject. Specifically, the present invention discloses a method and apparatus for laminating a sensor and inserting the sensor into a protective shield for use. The shield includes some adhesive material to affix the sensor to the subject. A dirty, damaged, or worn out shield may be discarded and the sensor inserted into a new shield for continued use of the sensor.

Abstract: The present invention provides a method and apparatus for adapting to noise sources affecting a pulse oximeter. Various available frequencies are evaluated to determine their respective noise levels and one is selected to act as the operating demultiplexer frequency. During normal operation of the pulse oximeter, the various available demultiplexer frequencies are periodically scanned to determine which has the lowest associated noise. The noise level associated with the operating frequency is used to determine the signal-to-noise ratio of the pulse oximeter signals and thereby qualify certain signals from the pulse oximeter. Those pulses associated with a signal-to-noise ratio below a predetermined threshold are rejected and excluded from use in calculating blood oxygen saturation.

Abstract: The lung ventilator safety valve includes a valve housing, an armature connected to the valve housing, a shaft mounted at one end to the armature and having a poppet valve seal on the other end for sealing the vent in a valve closed position and for allowing a relief flow in a valve open position. An electromagnetic coil mounted to the valve housing adjacent to the armature when energized urges the armature to the armature closed position, and a return spring urges the armature to an open position. The poppet valve seal has an aperture extending through the poppet valve seal, so that when there is relief flow through the safety valve vent, the relief flow across the poppet valve seal creates a jet venturi effect to cause a negative pressure on the side of the poppet valve seal opposite the relief flow that biases the safety valve to open further.

Abstract: The oxygen generation composition utilizes magnesium oxide to modify and smooth the oxygen generation rate, suppress chlorine formation, improve the rheology and uniformity of performance of an operating chemical oxygen candle, and to facilitate the mixing of the candle ingredients. The oxygen generation composition typically comprises a metal powder as a fuel; magnesium oxide; and an oxygen source selected from the group consisting of alkali metal chlorates, alkali metal perchlorates, and mixtures thereof. The composition can also include a transition metal oxide catalyst, and can include a binder.

Abstract: A device is directed to a ventilation control system for controlling the ventilation of a patient. The ventilation control system utilizes a user-friendly user interface for the display of patient data and ventilator status. The user interface includes a graphic representation of a breath cycle that displays the breath cycle currently being ventilated, and is also responsive to changes in ventilation settings to assist the user in evaluation the effect of those changes on the ventilator strategy before the changes are implemented.