Ohmeda Inc.

Kestrel Labs, Inc

Datex-ohmeda, Inc.

Other

Zynex Monitoring Solutions Inc.

Kestrel Lab, Inc.

Jonas Alexander Pologe

Theodore Philip Delianides

Kurt Albert Aronow

Kristin H Jarman

D Alan Hanna

Matthew A Gingrich

David W Trumble

Shao Yang

Robert M Tobin, Jr

A photoplethysmographic device includes a photoplethysmographic monitor, two or more emitters coupled to and controlled by the monitor, the emitters including at least one laser and at least one of the at least one lasers is a tapped laser configured to emit light through a primary optical path from the emitter to a sensor, and a photodetector coupled to the monitor and positioned to receive light tapped from the tapped laser prior to the point where the light exits the sensor, the photodetector generating an electrical signal indicative of the intensity of the amplitude of the light tapped from the tapped laser. The monitor processing the electrical signal to determine the condition of the tapped laser, whereby the monitor determines if the tapped laser is damaged and/or if one or more operating conditions of the tapped laser need to be altered.

Tapped light in a laser-based photoplethysmographic device

A method for calibration of a photoplethysmographic device including the steps of providing a fluid circuit () for blood or other liquid, a pump mechanism () to generate pulsatile flow of blood through the fluid circuit, a sample of excised tissue () in the fluid circuit through which the blood flows, and a photoplethysmographic device including an emitter and a photodetector () positioned on the tissue () so that a portion of the light output by the emitter passes through the tissue and is incident on the photodetector. The method further includes the steps of energizing the pump mechanism () to move the blood through the tissue, energizing the emitter () to output light, collecting paired data from the photodetector and from one or more reference measurements (), and processing the paired data to calibrate the photoplethysmographic device ().

Ex vivo calibration of a photoplethysmographic device

A photoplethysmographic device including at least one laser light source and further including a protective sensor connector that has a protective flap (), a mechanism () for controlling movement of the protective flap, and a plurality of interconnections, at least one of which is an optical connection (). The movement of the protective flap designed to provide at least a substantially open position and a substantially closed position.

Photoplethysmographic device with mechanically-protected sensor connector

An embodiment of a laser to fiber coupling apparatus having a substratethat supports a laser mount, to which is affixed a submountand laser die, and an open slot mount, in which a light guideis affixed with an adhesive, such that the light from the laseris coupled into the light guide. The open slot arrangement permits the light guide to be moved in all six translational and rotational degrees of freedom to maximally couple the light from the laser to the light guide. Other embodiments are described and shown.

Laser to fiber optical coupling in photoplethysmography

An embodiment of a light launching portion of a photoplethysmographic device having a laser () light source and a light guide (). The coupled end of the light guide () includes an anti-reflection coating () to prevent or minimize the back reflection of light emitted by the laser (). This minimizes the extent to which back reflected light can re-enter the laser and adversely alter the optical output properties of the laser () and additionally minimizes the associated light loss thus helping to maximize the optical coupling efficiency. Other embodiments are described and shown.

Anti-reflective launch optics for laser to fiber coupling in a photoplethysmograpic device

A photoplethysmographic sensor designed for use on the presenting portion of a fetus during labor and delivery. The sensor has a non-deployed state in which the sensor presents a smaller footprint, or cross sectional area, for transvaginal insertion. Once the sensor is applied to the fetal tissue it is moved into the deployed state, which has a larger footprint or cross sectional area, than the sensor does in the non-deployed state. The deployed state optimizes the physical distance between the light emitter and the photodetector to maximize the photoplethysmographic measurement accuracy from the fetal tissue.

Spring wing assembly for photoplethysmorgraphic sensor

A method and apparatus for photoplethysmographic measurements from non-human species is disclosed. The extinction of light by hemoglobin, as a function of wavelength, varies as a function of the species of the subject being monitored. The calibration of a photoplethysmographic device should therefore also vary dependant upon the species of the subject. The photoplethysmographic device of this invention includes calibrations specifically designed to provide accurate readings on non-human subjects.

Photoplethysmographic device with species-specific calibration

A method and apparatus for photoplethysmographic measurements is disclosed. In this system light from a plurality of emitters is delivered to the tissue-under-test. A subset of one or more of the emitters is known to be quiet light sources with relatively stable output intensity levels and spectral contents. A second subset of one or more emitters is known to be relatively noisy light sources with output intensity levels that fluctuate over time. The use of noisy light sources may be necessary for the photoplethysmographic measurements due to favorable spectral output characteristics such as narrow spectral bandwidth or desirable center wavelengths for the measurement of the hemodynamic parameters or analytes of interest. This invention utilizes the quiet light sources to enable the use of noisy light sources without the loss in accuracy or precision of analyte measurement that would otherwise typically be associated with the use of noisy light sources in the design and use of a photoplethysmographic instrument.

Stabilization of noisy optical sources in photoplethysmography

A hybrid optical system for photoplethysmographic measurements is disclosed. The system delivers light from a plurality of emitters to the tissue-under-test. A set of one or more of the emitters resides in close proximity to the sensor. A second set of one or more emitters resides at some distance from the sensor with the light from this second set of emitters being delivered to the sensor by a light pipe typically consisting of a fiber optic cable. This invention allows the photoplethysmographic instrument designer to use two or more different types of emitters in the same photoplethysmographic device while still generating a technically feasible and cost effective design.

Hybrid optical delivery system for photoplethysmography

A photoplethysmographic measurement system includes an electrical lockout to effectively prevent users, such as patients and medical personnel, from being exposed to high levels of light energy illuminating from light emitters ( ) housed within a main instrument ( ) when a probe ( ) becomes detached from the system during use. The probe ( ) is provided with a resistor having a range of resistor values. In use, the electrical lockout frequently or continuously interrogates the probe connection and determines whether the detected value of the resistor falls within predetermined allowable levels. If the probe ( ) inadvertently becomes disconnected from the main instrument, the value of the resistor will fall outside of the predetermined allowable levels indicative of an incompatible probe, an improper coupling of the probe, or a complete detachment of the probe. In this case, lockout switch ( ) is employed to inhibit activation of the light emitters ( ). When a proper connection is re-established, the electrical lockout will recognize the value of the detected resistor and send a signal to close the lockout switch ( ), allowing current to pass and re-energize the light sources. Alternatively or in addition, the electrical lockout may include a circuit or a mechanism for detecting a presence of a light sensor ( ) in the probe by checking for the appropriate forward voltage drop on the conductors ( ) connected to the light sensor.

Electrical lockout photoplethysmographic measurement system

The present invention is directed to a method and system for use in assessing collateral blood flow to a tissue region of interest (ROI). The method includes the steps of obtaining a first pulsatility measurement and a second pulsatility measurement, wherein one of the pulsatility measurements is obtained with a plurality of arteries supplying blood to the tissue ROI and the other pulsatility measurement is obtained with at least a selected one of such arteries substantially occluded. The method further provides for use of the first and second pulsatility measurements to generate a collateral flow value useful to medical personnel as an objective measure in assessing collateral blood flow to a tissue ROI. The method may further include the step of obtaining a check pulsatility measurement after obtaining a first pulsatility measurement and prior to obtaining a second pulsatility measurement, wherein all of the plurality of the arteries are substantially occluded. The check procedure enhances the reliability of a second pulsatility measurement obtained when a selected one of the arteries is substantially occluded.

Method and system for assessing collateral blood flow to a tissue region of interest

A system is provided for improving photoplethysmographic analyte measurements by de-emphasizing motion-contaminated data and/or emphasizing motion-free data. The system is used in a measurement instrument which includes at least illumination source for transmitting at least two light signals at two center wavelengths through a patient's appendage and a sensor for converting the light signals transmitted through the appendage into electrical output signals. The system includes a first buffer configured to temporarily store at least one pulse cycle of output signals received from the sensor A motion estimator quantifies an amount of motion associated with the output signals stored in the first buffer by performing a principal component analysis on differential absorption values derived from the output signals. Based on the amount of motion estimated, a weight application module is configured to associate a weight with the output signals in the first buffer. The weighted output signals are transferred into a second buffer which contains weighted output signals collected over multiple pulse cycles. An analyte computing module computes blood analyte related values based on the weighted output signals stored in the second buffer

Method and system for improving photoplethysmographic analyte measurements by de-weighting motion-contaminated data

A medical monitoring instrument such as a pulse oximeter uses vertical cavity surface emitting laser diodes (VCSELs) to produce at least two high intensity, essentially monochromatic light beams. The VCSELs are located either in: (1) the probe itself, (2) the connector to the probe, or (3) the monitor box connected with an optical fiber to the probe.

Noninvasive medical monitoring instrument using surface emitting laser devices

An improved method and apparatus for the photoplethysmographic monitoring of blood analyte parameters, specifically oxyhemoglobin, deoxyhemoglobin (reduced hemoglobin), carboxyhemoglobin and, in addition, in a four emitter apparatus, methemoglobin, uses a plurality of beams of light having different spectral contents to trans-illuminate the tissue of a patient. The apparatus and method require the application of an emitter set comprised of four emitters. The emitters may be LED's or laser diodes. In the three analyte system the center wavelength of the emitters must fall within three specific bands. In the four emitter system (capable of measuring methemoglobin) the center wavelength of the emitters in the emitter set must fall within four predetermined bands and the emitters having the two lowest center wavelengths must be at least 5 nanometers apart. The apparatus can use emitters which are located either in a probe, or, preferably, in the monitor, as well as a photodiode which can either be located in the patient probe or in the monitor.

Apparatus and method for improved photoplethysmographic monitoring of

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.

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Boulder, CO, United States of America

Jonas Alexander Pologe