Method and system for monitoring intracranial pressure

• US 20080077023A1
• Filed: 09/27/2006
• Published: 03/27/2008
• Est. Priority Date: 09/27/2006
• Status: Active Grant

• Current Assignee: Covidien LP (Medtronic Plc)
• Original Assignee: Nellcor Puritan Bennett Incorporated (Medtronic Plc)
• Inventors: Campbell, Shannon E., Baker, Clark R.
• Granted Patent: US 8,696,593 B2
• Time in Patent Office: Days
• US Class Current: 600/502
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/031 Intracranial pressure
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/6814 Head

Abstract

Embodiments of the present invention relate to a system and method for monitoring intracranial pressure. Embodiments of the present invention include emitting an electromagnetic wavelength into forehead tissue of a patient and detecting characteristics of the electromagnetic wavelength after the electromagnetic wavelength has been scattered by the tissue. The characteristics may include variations in the electromagnetic wavelength corresponding to a pulse. Further, embodiments of the present invention include analyzing the variations to identify venous pulsations, and determining whether intracranial pressure is elevated in the patient based on a correlation between the venous pulsations and levels of intracranial pressure.

Claims

1. A method for monitoring intracranial pressure, comprising:

emitting an electromagnetic wavelength into forehead tissue of a patient;

detecting characteristics of the electromagnetic wavelength after the electromagnetic wavelength has been scattered by the tissue, wherein the characteristics include variations in the electromagnetic wavelength corresponding to a pulse;

analyzing the variations to identify venous pulsations; and

determining whether intracranial pressure is elevated in the patient based on a correlation between the venous pulsations and levels of intracranial pressure.

2. The method of claim 1, comprising:

applying an increasing amount of pressure to the forehead tissue until the venous pulsations are abolished;

measuring the amount of pressure corresponding to abolishment of the venous pulsations; and

quantifying the intracranial pressure based on the measured amount of pressure.

3. The method of claim 1, comprising:

elevating the forehead tissue relative to the heart of the patient until the venous pulsations are abolished;

measuring the elevation corresponding to abolishment of the venous pulsations; and

quantifying the intracranial pressure based on the measured elevation.

4. The method of claim 1, comprising analyzing a shape of the variations to identify the venous pulsations based on a correlation between the shape and the venous pulsations.

5. The method of claim 1, comprising analyzing a phase difference between variations in multiple electromagnetic wavelengths to identify the venous pulsations based on a correlation between the phase difference and the venous pulsations.

6. The method of claim 1, comprising:

emitting a second electromagnetic wavelength into a different portion of the forehead tissue of the patient;

detecting characteristics of the second electromagnetic wavelength after the second electromagnetic wavelength has been scattered by the different portion of forehead tissue, wherein the characteristics of the second electromagnetic wavelength includes variations in the second electromagnetic wavelength corresponding to pulse; and

comparing a ratio of the variations in the electromagnetic wavelength and the variations in the second electromagnetic wavelength to identify the venous pulsations based on a correlation between the ratio and the venous pulsations.

7. The method of claim 1, comprising identifying the venous pulsations by comparing a first oxygen saturation estimate obtained from the forehead tissue and a second oxygen saturation estimate from a different portion of the forehead tissue.

8. The method of claim 1, comprising delivering a pharmaceutical to the patient to control elevated intracranial pressure when elevated intracranial pressure is determined to be present.

9. The method of claim 1, comprising comparing saturation values from multiple sites or comparing phase differences between a pulse and an ECG to identify the venous pulsations.

10. A sensor for monitoring intracranial pressure, comprising:

an emitter configured to emit at least one electromagnetic wavelength into tissue of a patient;

a detector configured to detect the at least one electromagnetic wavelength after scattering by the tissue; and

an adjustment measurement device configured to measure a level of adjustment corresponding to abolishment of venous pulsations detected using the emitter and detector.

11. The sensor of claim 10, wherein the adjustment measurement device is configured to measure an amount of pressure applied to the sensor.

12. The sensor of claim 10, wherein the adjustment measurement device comprises a pressure sheet.

13. The sensor of claim 10, wherein the adjustment measurement device is configured to measure an elevation relative to the heart of the patient.

14. The sensor of claim 10, comprising a headband configured to adjustably press the sensor against the patient.

15. A system for monitoring intracranial pressure, comprising:

a sensor comprising;

an emitter configured to emit at least one electromagnetic wavelength into tissue of a patient; and

a detector configured to detect the at least one electromagnetic wavelength after scattering by the tissue;

a monitor in electronic communication with the sensor, the monitor configured to analyze characteristics of the detected electromagnetic wavelength to identify venous pulsations; and

an adjustment measurement device configured to measure a level of adjustment corresponding to abolishment of identified venous pulsations.

16. The system of claim 15, comprising:

an inflatable headband; and

a pump configured to inflate the headband to increase pressure between the sensor and the tissue.

17. The system of claim 15, comprising an adjustable head elevator configured to elevate the tissue with respect to the heart of the patient.

18. The system of claim 15, wherein the monitor comprises a pressure mapping system.

19. The system of claim 15, wherein the monitor comprises a pulse oximeter.

20. A method, comprising:

providing an emitter configured to emit at least one electromagnetic wavelength into tissue of a patient;

providing a detector configured to detect the at least one electromagnetic wavelength after scattering by the tissue; and

providing an adjustment measurement device configured to measure a level of adjustment corresponding to abolishment of venous pulsations detected using the emitter and detector.

21. The method of claim 20, wherein the adjustment measurement device is configured to measure an amount of pressure applied to the sensor.

22. The method of claim 20, wherein the adjustment measurement device comprises a pressure sheet.

23. The method of claim 20, wherein the adjustment measurement device is configured to measure an elevation relative to the heart of the patient.