Abstract: A device and a method for measuring body fluid-related metrics using spectrophotometry to facilitate therapeutic interventions aimed at restoring body fluid balance. The specific body fluid-related metrics include the absolute volume fraction of water in the extravascular and intravascular tissue compartments, as well as the shifts of water between these two compartments. The absolute volume fraction of water is determined using algorithms where received radiation measured at two or more wavelengths are combined to form either a single ratio, a sum of ratios or ratio of ratios of the form log [R(&lgr;1)/R(&lgr;2)] in which the received radiation in the numerator depends primarily on the absorbance of water and the received radiation in the denominator depends primarily on the absorbance of water and the sum of the absorbances of non-heme proteins, lipids and water in tissue.

Abstract: A parameter of interest being measured by a sensor is estimated from output response data from the sensor and the known transfer function of the sensor, allowing fast and accurate sensor data from sensors having a dynamic characteristic otherwise precluding assessment of the sensor input. A parameter of breathing gas from a ventilator is determined based upon the known transfer function and a plurality of the sensor output signals at predetermined intervals of time, to provide an estimation of the parameter of interest.

Abstract: A pulse oximeter sensor having an emitter(s) and a detector, with a layer having a first portion of the emitter and a second portion of layer over the detector is provided. A barrier is included between the first and second portions of the overlying layer to substantially block radiation of the wavelengths emitted by the emitter(s). Preferably, the barrier reduces the radiation shunted to less than 10% of the radiation detected, and more preferably to less than 1% of the radiation detected.

Abstract: A pulse oximeter sensor having an emitter(s) and a detector, with a layer having a first portion of the emitter and a second portion of layer over the detector is provided. A barrier is included between the first and second portions of the overlying layer to substantially block radiation of the wavelengths emitted by the emitter(s). Preferably, the barrier reduces the radiation shunted to less than 10% of the radiation detected, and more preferably to less than 1% of the radiation detected.

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 and infrared signals correlated when used for pulse oximetry, and the resulting signals correlate to arterial oxygen saturation.

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: 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 and method of powering up a patient ventilator for detecting if a patient is connected to the ventilator when the ventilator is initially powered up prior to input of ventilator settings. 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: 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 and for setting and displaying appropriate alarms settings and patient data.

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. 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.

Abstract: A pulse oximeter sensor having an emitter(s) and a detector, with a layer having a first portion of the emitter and a second portion of layer over the detector is provided. A barrier is included between the first and second portions of the overlying layer to substantially block radiation of the wavelengths emitted by the emitter(s). Preferably, the barrier reduces the radiation shunted to less than 10% of the radiation detected, and more preferably to less than 1% of the radiation detected.

Abstract: A fetal sensor with a biasing mechanism for biasing the sensor against the fetus, with the biasing mechanism being automatically self-inflating and insertable in compressed form. The biasing mechanism in a preferred embodiment is a compressed foam or sponge which expands upon being exposed to fluid, such as amniotic fluid within the uterus. Thus, the biasing mechanism can be compressed to allow easy insertion, and then can expand once in place to provide the pressure needed to hold the sensor against the fetus.

Abstract: A pulse oximeter sensor having an emitter(s) and a detector, with a layer having a first portion of the emitter and a second portion of layer over the detector is provided. A barrier is included between the first and second portions of the overlying layer to substantially block radiation of the wavelengths emitted by the emitter(s). Preferably, the barrier reduces the radiation shunted to less than 10% of the radiation detected, and more preferably to less than 1% of the radiation detected. Additionally the shunt barrier is selected from a fibrous material, a woven material, and a compressible foam.

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 chlorate/perchlorate based oxygen generating compositions contain about 0.5-15% by weight of metal powder for use as a fuel selected from the group consisting of iron, nickel, cobalt and mixtures thereof; about 0.1% to about 15% by weight of at least one transition metal oxide catalyst; greater than 5% to about 25% by weight of an alkali metal silicate as a reaction rate and core rheology modifier, binder and chlorine suppresser; and the remainder substantially comprising an oxygen source selected from the group consisting of alkali metal chlorates, alkali metal perchlorates, and mixtures thereof. The alkali metal silicate can be selected from the group consisting of sodium metasilicate, sodium orthosilicate, lithium metasilicate, potassium silicate, and mixtures thereof. The oxygen generating composition can also optionally contain a binder selected from the group consisting of glass powder, fiber glass and mixtures thereof.

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: An apparatus is provided for controlling discharge of oxygen from an oxygen supply source to a patient. The apparatus includes an oxygen supply inlet, a pressure regulator coupled to the oxygen supply inlet and configured to reduce pressure of oxygen received from the oxygen supply inlet to a selected magnitude, a flow controller coupled to the pressure regulator and configured to meter oxygen received from the pressure regulator at a selected flow rate, and an oxygen distribution assembly including a pneumatic demand oxygen valve and a conduit conducting oxygen discharged from the flow controller through the pressure regulator to the pneumatic demand oxygen valve for delivery to a patient. The flow controller includes a chamber and a rotary valve for splitting oxygen discharged from the chamber into a first stream in an oxygen supply passageway for use by a patient and a second stream in a diaphragm supply passageway for controlling operation of pneumatic demand oxygen valve.

Abstract: An improved oximeter sensor structure for attaching to an appendage of a patient. The emitters and the detector are offset from each other, so that they are not directly opposite each other. This causes the light emitted by the emitters to pass through more blood-perfused tissue to reach the detector than it would on the direct path through the appendage if the emitters and detector were opposite each other.