Abstract: The respiratory gas analyzer (10), in one embodiment, is used for in-stream analysis of a patient breathing circuit (12). The analyzer includes a source (12) of infrared illumination, a modulator (28) for modulating the infrared illumination on a wavelength dependent basis to yield a modulated signal, a transmitter/detector unit (32) for transmitting the modulated signal through the breathing circuit (12) and detecting the transmitted signal, and a processing unit (34) for determining composition information regarding a sample under analysis based on the detected, modulated signal. The modulator (28) may include, for example, a Michelson interferometer for transforming the illumination into a frequency domain signal. The modulated signal allows for use of a compact detector system at the respiratory circuit interface. In addition, infrared fiber optics can be utilized to minimize instrumentation/optics at the interface.

Abstract: A photodetector is used to monitor contamination of optical elements within an optical system. The photodetector is aligned to detect nonspecular/diffuse reflections attributable to surface irregularities of particulate matter residing on the surfaces of the optical elements within the system. An increase in the intensity of the nonspecular reflections corresponds to increased levels of contamination on the surface of the optical element. An electronic detector circuit performs signal processing on the photodetector output signal and generates an output signal corresponding to the contamination level. In another aspect of the invention, the photodetector circuit is incorporated into a Raman gas analysis system.

Abstract: A patient probe disconnect alarm where the patient probe is provided with a vacuum that is formed in a chamber between the patient probe and the skin of the infant. The level of vacuum is monitored within the chamber and whenever the level of vacuum lessens beyond a predetermined vacuum level, the monitor senses a probe disconnect and provides an alert to the user that there is a loss of integrity in the probe affixation to the infant.

Abstract: The present invention is directed to a pulse oximeter sensor and an attached flexible carrier for measuring the oxygen saturation of a patient's blood. The carrier includes a compressible material, such as foam, for contacting the patient's skin and the sensor that applies a substantially uniform pressure to the skin.

Abstract: An alarm prioritizing system for use with a medical device categorizes the alarms into high, medium and low priority alarms. With the medium and high priority alarms, there is a visual indication and a audible sound that cannot be fully muted. With certain alarms, however, the operator can, by a positive and deliberate input, de-escalate the alarm priority from a medium priority alarm to a low priority alarm where the audible sound is muted and only a visual indication is thereafter provided. There is a time delay between the time the user actually starts the de-escalation process before it is effected to enable the user to properly identify the alarm and its location on a visual display panel. As a further feature, the same visual indication shifts from a medium priority alarm location to a low priority alarm location.

Abstract: The gas sample identification apparatus transmits at least one beam of light of predefined frequency band through a gas sample present in a gas sampling chamber. The presence and concentration of various agents in the gas sample are determined by a linear variable filter that selectively passes the light beam transmitted through the gas sample chamber to an array of detectors. The detectors are positioned to receive only a narrow passband component of the light beam. The output signals from the array of detectors is processed by a multivariate statistical processor to accurately identify both the presence and concentration of one or more agents contained in the gas sample.

Abstract: The present invention is directed to an oximeter sensor to measure the oxygen content of a patient's blood. The sensor can include a lead frame having different thicknesses, a sensor housing being molded from a common thermoplastic resin, and rib members in the housing for inhibiting shorting between adjacent traces of the lead frame. The present invention further includes a process for forming the sensor.

Abstract: A mechanism for aligning the elements of an optical system is disclosed. One aspect of the present invention is an alignment mechanism which includes lead screws placed on opposite corners of the elements to be aligned. The elements are provided with threaded holes of different pitch, and the lead screw is provided with threads of the same unequal pitches as the elements, thereby forming a differential lead screw. The threads include a locking thread which assures a positive lock between the lead screw and the elements to be aligned and eliminates backlash between them. Another aspect of the present invention is an interference fit mechanism which is provided by the employment of a slightly-oversized flexible boss which mates with a cavity. The boss is provided with a thin outer wall capable of flexing when the boss is inserted into the cavity. Yet another aspect of the present invention includes a wobble plate comprising a spherical socket and housing.

Abstract: The device for producing a display from monitored data functions to read, store, encode, and integrate monitored data of at least one data type from at least one monitoring device so that the related or unrelated datum is comprehensible at a glance by a user. Encoding data of a particular data type produces a color indicia and a graphic indicia that are the basic integration components. Integrating indicia of at least one data type produces a single superimposed and/or multidimensional image capable of portraying a present and historical data combination reflecting the monitored data's relative value at some point in time.

Abstract: An ultrasonic transducer is disclosed for emitting an ultrasonic wave radially inward. The transducer is constructed with a strip of piezoelectric material laminated with a pair of electrically conductive metal layers that are conductively isolated from one another. In a preferred embodiment, the strip of piezoelectric material is formed in a cylindrical shape and with continuous sinusoidal ripples along the circumference. The sinusoidal ripples are designed to emit a specific wave length of a desired frequency. The radius of the sinusoidal wave is based on material characteristics and the desired resonance frequency. The invention discloses various methods and apparatus for constructing and maintaining the transducer sinusoidal shape. One method includes attachment of a pair of rigid end caps on the laminated piezoelectric material, and another discloses weaving the laminated piezoelectric material through a nonconductive mesh cage, and yet another includes adhesively attaching the transducer to a housing.

Abstract: A two-stage statistical calibration and measurement method and system is disclosed for performing photoplethysmographic measurement of blood analyte concentrations. Concentrations in a tissue sample of MetHb, O.sub.2 Hb, RHb and COHb are estimated by first estimating a concentration of MetHb (in a first stage) and subsequently, if the concentration of MetHb is within a predetermined range, then the estimated concentration of MetHb is assumed to be accurate and this estimated concentration of MetHb is utilized as a "known value" in determining the concentrations of the remaining analytes O.sub.2 Hb, RHb and COHb (in a second stage). That is, by eliminating one "unknown" from the system of equations, these remaining analytes can be calculated with increased accuracy. Each stage is performed using data obtained by transmitting light through the tissue sample (typically a finger or earlobe). The transmitted light is generated by four discrete light emitters, each emitter having a distinct spectral content.

Abstract: A photoplethysmographic measurement device that utilizes wavelength division multiplexing is provided. Signals from multiple light emitters are combined into a single multiplexed light signal in a test unit before being delivered to a physically separated probe head attached to a test subject. The probe then causes the single multiplexed signal to be transmitted through a tissue under test on the test subject, after which it is processed to determine a blood analyte level of the test subject. By combining the light signals into a single multiplexed signal before delivering the signals to the probe, a single light guide, such as a single optical fiber, can be used to deliver the signals to the probe, thereby reducing system implementation cost and increasing the flexibility of the probe cable. In addition, the invention allows the signals from the light emitters to be directed into the test subject from a single point source, which can significantly increase measurement accuracy.

Abstract: A medical device includes a hollow needle having a distal tip for piercing the skin of a patient. A housing is provided for moving the needle relative to said housing between a first ready-for-use position and a second retracted needle protected position. A resilient arm is attached to the housing, said arm having a free end which in the second retracted needle protected position of the needle, engages said needle to move said distal tip laterally.

Abstract: An infant incubator having an infant compartment that contains the infant and which is set to a desired temperature above ambient by the user. The incubator has at least one access door that opens to allow the caregiver to perform an intervention on the infant and which is actively heated when in the open position. Thus, when the access door is again closed, the door is at an elevated temperature with respect to the ambient and less heating energy is needed to return the infant compartment back to the desired temperature.

Abstract: A heated humidifier for an infant incubator wherein the water in the water reservoir is heated by an active heater located above the surface of the water and a heat exchanger that transfers heat from the active heater and which extends downwardly to a point beneath the water surface to heat the water. In the preferred embodiment, the heat exchanger is an extruded member in the shape of an I-beam to transfer the heat from an electric heater above the surface of the water to heat the volume of water in the reservoir to create water vapor.

Abstract: A system for automatically refilling the patient breathing circuit of an anesthesia system wherein the system detects the existence of a large leak in the patient breathing system and reduces the flow of the fresh gas to the patient circuit to minimize the amount of gas that is vented to the atmosphere. As the leak is corrected, the system automatically detects that the leak has been alleviated and increases the fresh gas flow to a high flow to refill the patient breathing circuit in a rapid time. Upon refill, the system detects that the circuit and the system has been refilled and automatically reduces the fresh gas flow back to a lower level desired by the clinician to maintain the anesthesia. The fresh gas flow used to refill the patient circuit is the same composition of gases and anesthetic agent as initially set by the clinician.

Abstract: This apparatus places the laser diode light source in the connector affixed to the distal end of the cable, proximate to the patient. The disposable portion of the probe simply consists of the apparatus required to affix the probe to the patient's appendage and the mating portion of the connector that interconnects with the cable. The disposable portion of the probe can be a minimalistic design since all the expensive elements are located in the medical monitoring instrument or the cable connector.

Abstract: An improved method and apparatus for the photoplethysmographic monitoring of blood analyte parameters, specifically oxyhemoglobin, deoxyhemoglobin (reduced hemoglobin), carboxyhemoglobin and methemoglobin, uses a plurality of beams of light having different spectral contents to trans-illuminate the tissue of a patient. Received light is measured and the normalized differential absorption is used in a forward calibration equation to generate estimated relative blood analyte concentration values. Error in the blood analyte concentration values is minimized by applying constraints to the estimated analytes. Specifically, the constraints require that all relative analyte concentration values are greater than or equal to zero and sum to one hundred percent.

Abstract: The present invention is directed to a charge coupled device in which, during the shifting interval, the charge storage pixels are biased with an electrical potential greater than the absolute value of the CCD inversion potential and, during the charge integration interval, the charge storage pixels are biased with an electrical potential that is less than the CCD inversion potential. In this manner, the present invention substantially reduces error attributable to impact ionization or dark current.

Abstract: An audible waveform system is provided that senses a parameter relating to the ventilation of a patient. The system produces short bursts of sound of a predetermined frequency as the changes occur in that parameter based on certain increments of change. The bursts themselves are preferable at a frequency that is the same for equal pressures but increases and decreases in frequency as the parameter increases or decreases, respectively. In the preferred embodiment, the system provides an audible waveform based on the pressure in the patient airway so that the clinician can receive information relating to that waveform conveniently and without taking attention away from other monitors and/or alarms.