Hemoglobinometers and the like for measuring the metabolic condition of a subject

Abstract

The present invention discloses a novel, user-wearable system for monitoring the oxygen concentration, or oxygenation trend, in the tissue of a subject undergoing aerobic stress. The system comprises a lightweight detector, worn against the skin surface of the subject, at the site being monitored. The system further includes wearable power pack and display means for displaying information indicative of the metabolic condition of the region being monitored. The detector preferably employs a continuous wave spectrophotometer having one or more sources of electromagnetic radiation with wavelengths between about 760 and 800 nanometers directed into the tissue of the subject. The detector utilizes photon migration to detect the portion of the transmitted radiation arriving at an adjacent skin region. The present invention also discloses methods for displaying the aerobic metabolic condition of a subject.

Description

BACKGROUND OF THE INVENTION [0001] In one aspect, the present invention relates to wearable apparatus for noninvasive determinations of the concentration of oxygen in a specific target region of tissue. More specifically, the present invention discloses a user-wearable system for monitoring the oxygen concentration, or oxygenation trend, in the tissue of a subject undergoing aerobic stress, such as an exercising person. [0002] The increasing popularity of all forms of exercise over the last several decades has also lead to an increased interest in the measurement of individual athletic performance. However, at the present time, athletes are limited to obtaining heartbeat and blood pressure data while they are exercising. Although of some use, these data do not reflect peripheral circulatory capacity or the oxygenation state of specific muscle tissue. [0003] In order to measure oxygen delivery to the capillary bed of the muscles, an athlete must be tethered to electrocardiogram appar...

AI Technical Summary

Benefits of technology

[0008] The present invention provides a novel, wearable system for determining the metabolic condition of an aerobically stressed portion of the muscle tissue of an exercising person. The system comprises a lightweight rugged detector, worn against the skin surface of the subject, adjacent to the muscle being monitored. The system of the present invention thus minimizes any performance impairment. The preferred system further comprises a wearable power pack and a wearable display means for displaying information indicative of the aerobic metabolic condition of the region being monitored. In a preferred embodiment intended for use while running or engaged in similar athletic activities, the display is worn on the wrist and displays information from a leg-mounted detector. In another embodiment, intended to provide information to coaches, a telemetry system is employed to transmit a signal carrying the data from the detector to a remote location, for processing and display.

[0009] The detector of the present invention preferably employs a continuous wave spectrophotometer having one or more sources of electromagnetic radiation with wavelengths between about 760 nanometers and about 800 nanometers directed into the tissue of the subject. The detector is efficiently coupled to the body tissue and utilizes the principle of photon migration to detect the portion of the transmitted radiation arriving at an adjacent skin region.

[0011] It is an object of the present invention to provide methods and apparatus which allow a rapid determination of the oxygenation state of tissue, such as muscle tissue, located beneath the surface of the skin of a subject, such as an athlete, without requiring the subject to be tethered or physically connected to laboratory or operating room monitoring equipment.

[0022] According to another aspect of the invention, an oximeter is provided comprising a flexible support member comprised of a molded-elastomeric backing member, the backing member mounting at least one light source means capable of producing one or more (e.g., two) selected wavelengths and oriented to direct the light to tissue of a user and the backing member also mounting detector means capable of separately detecting energy at each of the wavelengths scattered by tissue of the user, integral elastomeric portions of the backing member defining a barrier exposed for conformable contact with an exposed surface of the user, in position to prevent lateral movement of light in subcutaneous layers from the source means to the detector means.

[0023] According to another aspect of the invention, an oximeter is provided comprising a flexible support member, the support member mounting at least one light source means capable of producing two selected wavelengths and oriented to direct the light to tissue of a user and the support member mounting detector means capable of separately detecting energy at each of the wavelengths scattered by tissue of the user, the support member supporting a barrier member exposed for conformable contact with an exposed surface of the user in position to prevent lateral movement of light from the source means to the detector means, the barrier comprising a member having an edge sized and positioned to indent skin and the flesh of the user thereby to intercept light migrating laterally in the subcutaneous fat layer and prevent such light from reaching said detector means.

[0044] The method is provided of monitoring a person suspect of sleep apnea or sudden infant death syndrome including providing to the person a comfortable oximeter sensor capable of automatically responding to oxygen level of the person while permitting the person to sleep, automatically monitoring the output of the oximeter by comparing it to a standard and generating a signal, such as a warning or control signal, in the event the monitored level violates a pre-established standard. Preferably the oximeter sensor is taped comfortably to the head for monitoring. Also, preferably the method is used in conjunction with impedance pneumography (breathing rate measurement using chest-wall impedance) and / or EKG to provide an effective in-home apnea monitor to alarm the patient or other individuals in the area so as to wake the patient and prevent hypoxic tissue damage during sleep.

Problems solved by technology

However, at the present time, athletes are limited to obtaining heartbeat and blood pressure data while they are exercising.

Although of some use, these data do not reflect peripheral circulatory capacity or the oxygenation state of specific muscle tissue.

For example, as a casual jogger strives to become a marathon runner, the efficiency at which he / she uses oxygen can severely impact performance; data reflecting the utilization of oxygen can provide information which allows an athlete to change pacing strategies or otherwise adjust their activity to produce better results.

Although apparatuses which measure the oxygenation content of blood using data collected from a fingertip or ear lobe are available, these devices do not actually measure the oxygenation state of nearby muscle groups or the brain.

While these techniques eventually might be able to provide examination and screening for neuronal deterioration and / or deterioration of brain function, they are relatively expensive and not suitable for emergency treatment situations wherein the diagnostic equipment should be taken to a patient.

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