Abstract: A method for calibration of a photoplethysmographic device including the steps of providing a fluid circuit (305) for blood or other liquid, a pump mechanism (310) to generate pulsatile flow of blood through the fluid circuit, a sample of excised tissue (315) in the fluid circuit through which the blood flows, and a photoplethysmographic device including an emitter and a photodetector (330) positioned on the tissue (335, 340) 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 (420) to move the blood through the tissue, energizing the emitter (425) to output light, collecting paired data from the photodetector and from one or more reference measurements (430), and processing the paired data to calibrate the photoplethysmographic device (435).

Abstract: A photoplethysmographic device including at least one laser light source and further including a protective sensor connector that has a protective flap (350), a mechanism (340) for controlling movement of the protective flap, and a plurality of interconnections, at least one of which is an optical connection (240). The movement of the protective flap designed to provide at least a substantially open position and a substantially closed position.

Abstract: A method for calibration of a photoplethysmographic device including the steps of providing a fluid circuit (305) for blood or other liquid, a pump mechanism (310) to generate pulsatile flow of blood through the fluid circuit, a sample of excised tissue (315) in the fluid circuit through which the blood flows, and a photoplethysmographic device including an emitter and a photodetector (330) positioned on the tissue (335, 340) 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 (420) to move the blood through the tissue, energizing the emitter (425) to output light, collecting paired data from the photodetector and from one or more reference measurements (430), and processing the paired data to calibrate the photoplethysmographic device (435).

Abstract: A photoplethysmographic device including at least one laser light source and further including a protective sensor connector that has a protective flap (350), a mechanism (340) for controlling movement of the protective flap, and a plurality of interconnections, at least one of which is an optical connection (240). The movement of the protective flap designed to provide at least a substantially open position and a substantially closed position.

Abstract: A replaceable optical subsystem for a laser-based photoplethysmographic monitor. At least one laser light source (200) is located in an optical subsystem (110) that can be easily detached from the monitor (110). The optical subsystem is attached to the monitor with the aid of a listening element (170) and communicates with the monitor via a monitor connector (160). The patient cable and sensor system, for delivery of the signals to and from the tissue-under-test, attach to the optical subsystem via a sensor connector (150). Other embodiments are described and shown.

Abstract: An embodiment of a laser to fiber coupling apparatus having a substrate 110 that supports a laser mount 120, to which is affixed a submount 130 and laser die 140, and an open slot mount 150, in which a light guide 160 is affixed with an adhesive 170, such that the light from the laser 140 is coupled into the light guide 160. 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.

Abstract: An embodiment of a light launching portion of a photoplethysmographic device having a laser (20) light source and a light guide (40). The coupled end of the light guide (40) includes an anti-reflection coating (30a) to prevent or minimize the back reflection of light emitted by the laser (20). This minimizes the extent to which back reflected light can re-enter the laser and adversely alter the optical output properties of the laser (20) and additionally minimizes the associated light loss thus helping to maximize the optical coupling efficiency. Other embodiments are described and shown.

Abstract: An embodiment of a laser to fiber coupling apparatus having a substrate 110 that supports a laser mount 120, to which is affixed a submount 130 and laser die 140, and an open slot mount 150, in which a light guide 160 is affixed with an adhesive 170, such that the light from the laser 140 is coupled into the light guide 160. 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.

Abstract: An embodiment of a light homogenizing apparatus having one or more emitters (110, 120) incident on a light mixing element. The emitters including at least one laser light source. The light mixing element comprising a diffuser (130) followed by an internally reflective light guide (160). This apparatus substantially homogenizes light from all emitters (110, 120) before light exits the internally reflective light guide (160) where it could then be incident on living tissue for use in photoplethysmographic measurement. Other embodiments are described and shown.

Abstract: One embodiment of an optical coupling for use in a photoplethysmographic device having a first light guide (160) with core (150) that mates to a second light guide (210) that has a core (220) with a diameter and numerical aperture that are larger than those of the first light guide. This results in a high-throughput optical coupling that is insensitive to lateral offset and angular misalignments of the light guide axes. It allows the use of lower-cost, lower-precision molded parts in the manufacture of optical connectors, yet maximizes the light that is available for delivery to the tissue-under-test. Other embodiments are described and shown.

Abstract: An embodiment of a light delivery portion of a photoplethysmographic device having a series of two or more optical elements. The series of two or more optical elements (20, 40, 50) are arranged to conduct light (10) from a laser and at least two consecutive elements of the series of two or more optical elements are coupled together by a non-reflective coupling (30a, 30b). 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 light loss associated with back reflection thus helping to maximize the optical throughput. Other embodiments are described and shown.

Abstract: An embodiment of a light launching portion of a photoplethysmographic device having a laser (20) light source and a light guide (40). The coupled end of the light guide (40) includes an anti-reflection coating (30a) to prevent or minimize the back reflection of light emitted by the laser (20). This minimizes the extent to which back reflected light can re-enter the laser and adversely alter the optical output properties of the laser (20) and additionally minimizes the associated light loss thus helping to maximize the optical coupling efficiency. Other embodiments are described and shown.

Abstract: 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.

Abstract: 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.

Abstract: 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.