Method and device for measuring parameters of cardiac function
Inventors
Assignees
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Publication Number
US-8918153-B2
Publication Date
2014-12-23
Expiration Date
Abstract
A device for non-invasively measuring at least one parameter of a cardiac blood vessel in a patient is provided. The device comprises at least one light source that emits light in the 400 nm to 1000 nm wavelength range; at least one photodetector adapted to receive light emitted by the light source and generate an output based on the received light, wherein said light is reflected from or transmitted through tissue of the patient, the output of said photodetector being correlated with a parameter of the blood vessel; and at least one probe for facilitating delivery of light from the light source to an external tissue site on the patient in the proximity of the cardiac blood vessel and receipt of light by the photodetector. A system and methods of monitoring/measuring cardiac parameters utilizing the device and/or system are also provided.
Core Innovation
The invention provides a device useful to determine central venous pressure in a patient using light in the 400 nm to 1000 nm wavelength range. A probe facilitates delivery of the light from at least one light source to an external tissue site on the patient in the proximity of the jugular vein, and receives light reflected from or transmitted through the patient tissue at the same site. Adjacent photodetectors sequentially receive the emitted light and translate the light into a recordable output derived from reflected or transmitted tissue light.
The device uses an array of adjacent photodetectors adapted to receive light reflected from or transmitted through patient tissue, with photodetectors adjacent along a length of about 1.5 to 10 cm. The optical input and photodetector output are processed to produce a visual waveform or output signal related to central venous pressure and a central venous pulse. Signal processing includes generating waveforms and applying multi-wavelength and multi-source concepts using a modified Beer-Lambert’s law with chromophores such as hemoglobin.
For central venous pressure determination, the invention specifies locating a highest position along the jugular vein that yields a waveform relative to a reference point, with the central venous pressure calculated using vertical distances relative to the reference point. The reference point may be described as the sternal angle or the phlebostatic axis, and compensation is provided for an inclination angle of the patient. In one described device implementation, height information is obtained using a height sensor comprising a pressure sensor connected to a patch via a tube, enabling calculation based on vertical distance and angle of inclination.
Claims Coverage
The provided partial content includes two independent claims directed to a central venous pressure determining optical device with a jugular-proximal patch probe and adjacent photodetector array, and a central venous pressure determining device that further specifies a height sensor comprising a pressure sensor connected to a patch via a tube. Across these independent claims, the inventive coverage centers on combining a wavelength-limited light source with a sequential adjacent photodetector array to convert reflected or transmitted tissue light into a recordable output, and calculating central venous pressure using reference-point geometry along the jugular vein with inclination-angle compensation.
Jugular-proximal light delivery with adjacent photodetector array for recordable output
A device useful to determine central venous pressure in a patient comprising at least one light source adapted to emit light in the 400 nm to 1000 nm wavelength range; an array of adjacent photodetectors adapted to sequentially receive light emitted by the light source and translate said light into a recordable output wherein said light is reflected from or transmitted through tissue of the patient, wherein the photodetectors are adjacent along a length of about 1.5 to 10 cm; and at least one probe which facilitates delivery of light from the light source to an external tissue site on the patient in the proximity of the jugular vein and receipt of light reflected from or transmitted through said patient site by the photodetectors.
Height sensor comprising pressure sensor connected to patch via tube
A device useful to determine central venous pressure in a patient comprising at least one light source adapted to emit light in the 400 nm to 1000 nm wavelength range; an array of adjacent photodetectors adapted to sequentially receive light emitted by the light source and translate said light into a recordable output wherein said light is reflected from or transmitted through tissue of the patient, wherein the photodetectors are adjacent along a length of about 1.5 to 10 cm; at least one probe which facilitates delivery of light from the light source to an external tissue site on the patient in the proximity of the jugular vein and receipt of light reflected from or transmitted through said patient site by the photodetectors; and a height sensor comprising a pressure sensor connected to a patch via a tube.
Across the independent claims, the core claimed coverage is the central venous pressure determining device that delivers 400 nm to 1000 nm light via a probe near the jugular vein, receives reflected or transmitted tissue light using an adjacent photodetector array to produce a recordable output, and includes an additional height sensor comprising a pressure sensor connected to a patch via a tube in the second independent claim.
Stated Advantages
Not explicitly described in patent.
Documented Applications
Not explicitly described in patent.
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