System and method for non-invasive monitoring of cerebral tissue hemodynamics

Inventors

Cheng, Xuefeng

Assignees

Mespere Lifesciences Inc

Abstract

A method and system are provided which are useful for the non-invasive determination and monitoring of cerebral blood oxygenation in a patient. The system comprises a first module for optically generating at least first and second internal jugular venous output signals against time at at least first and second wavelengths of light; and a second module for generating first and second cardiac arterial output signals at the first and second wavelengths of light, respectively. The system may additionally include a third module for optically generating at least first and second external jugular venous output signals against time at at least first and second wavelengths of light, and one or more cerebral modules for optically generating at least first and second local cerebral output signals against time at at least first and second wavelengths of light. The system includes a signal processing means adapted to calculate average cerebral, arterial, venous scalp and local cerebral blood oxygenation values based on the output from each of the modules.

Core Innovation

A system is described for optically monitoring cerebral tissue oxygenation in a patient using multi-wavelength light and internal jugular venous measurements. First and second internal jugular venous output signals are generated as current or voltage based on change in blood volume over time at first and second wavelengths of light using at least one light source and at least one photodetector receiving transmitted or reflected light. A pulse oximeter generates first and second cardiac arterial output signals over time at the first and second wavelengths of light.

The system calculates average cerebral blood oxygenation based on the internal jugular venous output signals, calculates arterial blood oxygenation based on the cardiac arterial output signals, and calculates cerebral tissue oxygenation based on the difference between average cerebral blood oxygenation and arterial blood oxygenation. The described approach separates or subtracts an arterial component from the optical measurements to obtain cerebral venous signals and compute cerebral oxygenation based on modified Beer-Lambert-based processing.

The description further provides optional modules for scalp venous oxygenation and local cerebral oxygenation, including external jugular venous output signals and one or more cerebral site modules (StO2). Comparisons among local cerebral, average cerebral venous, scalp venous, and scalp arterial oxygenation are used to detect or locate cerebral ischemia. The system architecture includes optical hardware and signal processing hardware for generating output signals over time and producing computed oxygenation outputs.

Claims Coverage

Two independent claims are present: one directed to a system and one directed to an amended application method. Each independent claim includes multiple inventive features centered on multi-wavelength optical venous measurements, pulse oximeter arterial signals, and computing cerebral tissue oxygenation from differences between venous and arterial oxygenation.

Across the independent claims, the core inventive concept is generating multi-wavelength internal jugular venous output signals and corresponding pulse oximeter arterial output signals, then calculating cerebral tissue oxygenation from the difference between average cerebral venous blood oxygenation and cerebral arterial blood oxygenation.

Stated Advantages

Documented Applications

No documented applications found