Spacelabs Medical, Inc.

David R Marble

Jonathan Tien

Stephen C Rafert

Glenn W Pelikan

Alan Kahn

An optoelectronic pulse oximetry sensor is described which physically conforms to a body portion of a patient, such as a finger, and provides a firm pressing engagement between the sensor and the patient's body portion. The sensor includes a flexible substrate, such as an elastic bandage-type material, which is physically conformable and attachable/adherable to the patient's body portion. The sensor also includes a light source assembly for transilluminating the patient's body portion, and a light detector assembly for measuring transmitted light. The dimensions of the light source and light detector assemblies are constructed to provide a high aspect ratio relative to the flexible substrate. When the sensor is conformably applied to the patient's body portion, localized pressure is exerted on the body portion at the points of contact with the light source and light detector assemblies, thereby stressing the skin and the underlying blood-perfused tissue. The stress imparted to the skin and underlying tissues affects the distributions of blood in the tissues and provides improved accuracy and sensitivity in arterial oxygen saturation measurement, especially in circumstances of low perfusion.

Conformal pulse oximetry sensor and monitor

A technique for the algebraic derivation of a pulse oximetry signal uses the mathematical relations of detected light signals. First and second light sources transmit light through the patient's finger or reflects light off the blood vessels in the patient's finger. A light detector detects light from each of the light sources and generates a measured intensity signal. The measured intensity signal includes the true intensity of light transmitted from each of the light sources as well as noise introduced during the measurement process. A data sample from each of the light sources is digitized and subdivided into a plurality of data windows. The mathematical relationship is applied to each of the data windows to determine a ratio value indicative of oxygen saturation in the patient. The ratio values are statistically analyzed to determine the best estimate for the correct ratio value. This ratio value is subsequently processed to determine the oxygen saturation within the patient.

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Seattle, WA, United States of America

David R Marble