Colin Electronics Co., Ltd.

Nippon Colin Co., Ltd.

Jonathan P Jaeb

Ronald L Branstetter

Dennis W Gilstad

Hiroshi Sakai

Merle E Converse

Setsuo Takatani

Jeffrey M Gabelmann

A noninvasive oximeter sensor for controlling and optimizing the minimum detection depth in the tissue of a patient is disclosed. In general, a minimum detection depth of 0.35 mm in the skin is considered optimum. The reflectance oximeter sensor component configuration of the present invention achieves the minimum detection depth. The present invention offers a more accurate indication of blood oxygen saturation in a patient's arterial blood than was available from previous reflectance oximeter sensors.

Noninvasive reflectance oximeter sensor providing controlled minimum

An oximeter system for measuring blood oxygen saturation using a noninvasive optical technique is disclosed. A patient's arterial blood is illuminated with light at two different wavelengths and the intensity of the light which is transmitted through or reflected by said arterial blood is correlated with the blood oxygen saturation of the tissue. The system provides a manner in which filtering artifacts are avoided in the oximeter signal using a high resolution analog-to-digital converter of 14 bits or more, such that, it is unnecessary to separate the DC and pulsatile components of the oximeter signal prior to processing within the microprocessor.

Composite signal implementation for acquiring oximetry signals

A system for measuring blood oxygen saturation uses a noninvasive optical technique. A patient's arterial blood is illuminated with light at two different wavelengths and the intensity of the reflected light is correlated with an oxygen saturation reference curve to determine the oxygen saturation of the patient's blood. The optical sensor includes one or more controlled heat sources which are used to maintain the patient's tissue at a predetermined temperature. Safety circuits are also provided in order to prevent thermal burns to a patient in the event of a system failure.

Oximeter sensor temperature control

An improved biological signal detector which is extremely sensitive, yet resistant to the effects of high frequency noise. A multiplexed signal representation of a plurality biological signals is demultiplexed by a detector circuit comprising a plurality of switches each of which controls an individual storage network. A switch logic control circuit synchronizes the various switches to close during the time intervals corresponding to the pulse amplitudes representing the particular signal of interest. The amplitude of the alternating component of each of the biological signals is stored in one of the respective storage networks over a number of pulse time intervals. In the preferred embodiment, the storage networks of the detector each have a time constant which is purposely chosen to be substantially longer than the time interval of the pulses. The long time constant of the storage networks allows the detector circuit to track changes in amplitude which manifest themselves over a relatively large number of time intervals, but prevents the detection of high frequency noise signals which may be present during the sampling intervals.

Noise rejecting detector for biomedical signals

An improved optical sensor which has increased sensitivity and which is resistant to the effects of ambient light. In one embodiment of the invention, the sensor housing has a flat lower face with a central protrusion in which a plurality of light emitting diodes and an optical sensor are mounted. When the sensor is placed on the patient's tissue, the portion of the sensor face containing the LEDs and detector protrudes slightly into the tissue to provide improved optical coupling of the sensor to the skin. A light absorbing compliant material is attached to the perimeter of the sensor to reduce the effects of ambient light and to provide a cushion to minimize discomfort to the patient. In an alternate embodiment of the sensor, the LEDs and detector are mounted in a horizontal configuration substantially parallel to the surface of the tissue. The light produced by the LEDs is projected into a central chamber of the housing where the respective beams are combined and directed toward the tissue. In this emodiment, the desired combining of the beams can be achieved through the use of a set of mirrors or a prism. Various combinations of the improvements provided by each of the embodiments described above can be incorporated into either a transmission or backscatter optical sensor to provide a compact, sensitive optical sensor which is resistant to interference caused by ambient light.

Growing community of inventors

San Antonio, TX, United States of America

Jonathan P Jaeb