DEVICE AND METHOD FOR DETERMINING A PARTIAL CARBON DIOXIDE PRESSURE IN A SUBJECT OF INTEREST

• US 20160029973A1
• Filed: 06/13/2014
• Published: 02/04/2016
• Est. Priority Date: 06/13/2013
• Status: Active Application

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: KAHLMAN, Josephus Arnoldus Henricus Maria
• Application Number:
  US14/776,747
• Publication Number:
  US 20160029973A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 5/01 Measuring temperature of body parts ; Diagnostic temperature sensing, e.g. for malignant or inflamed tissue clinical contact thermometers G01K13/20
• CPC Class Codes: A61B 5/015 By temperature mapping of body part
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/7278 Artificial waveform generation or derivation, e.g. synthesising signals from measured signals A61B5/327 takes precedence
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0063 Compressors
• CPC Class Codes: A61M 16/021 operated by electrical means A61M16/202 – A61M16/205 take precedence
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 2016/102 Measuring a parameter of the content of the delivered gas
• CPC Class Codes: A61M 2202/0208 Oxygen
• CPC Class Codes: A61M 2202/0266 Nitrogen (N)
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2230/202 partial carbon oxide pressure, e.g. partial dioxide pressure (P-CO2)
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/208 pH-value
• CPC Class Codes: A61M 2230/50 Temperature

Abstract

The present invention relates to a device (30) and a related method for determining a blood gas partial pressure in blood in a circulatory system of a subject (12) of interest. Also a system for ventilating a patient is disclosed. Temperature-related measurement values indicative of given blood temperature levels are detected. Oxygen saturation measurements of the blood of said subject (12) under consideration of said temperature-related measurement values are derived. A blood gas partial pressure of a monitored subject (12) from said derived oxygen saturation measurements is determined under consideration of present blood temperature levels of said subject (12). Preferably, pH-representative values attributable to present blood pH-values of the subject (12) are determined. More preferably, the pH-representative values are derived from an oxygen dissociation curve under consideration of changes in said derived oxygen saturation measurements of the blood attributable to detected temperature-related measurement values of the subject'"'"'s blood.

Claims

1. A device for unobtrusively determining a blood gas partial pressure in blood in a circulatory system of a subject of interest, the device comprising:

a non-obtrusive temperature detector for detecting temperature-related measurement values indicative of present intrinsic natural blood temperature level differences;

a non-obtrusive oxygen saturation sensor for deriving oxygen saturation measurements of the blood of said subject under consideration of said temperature-related measurement values; and

a blood gas pressure processor for determining a blood as partial pressure of the monitored subject from said derived oxygen saturation measurements under consideration of said temperature-related measurement values indicative of the present blood temperature level differences of said subject.

2. The device as claimed in claim 1, wherein the blood gas partial pressure is a partial carbon dioxide pressure, wherein the blood gas pressure processor is arranged as a partial carbon dioxide pressure processor, and wherein the blood gas pressure processor is further configured for determining pH-representative values attributable to present blood pH-values of the subject.

3. The device as claimed in claim 1, wherein the temperature detector is further configured for monitoring at least two measurement zones at the subject'"'"'s skin, wherein the at least two measurement zones exhibit different blood temperature levels.

4. The device as claimed in claim 1, wherein the temperature detector is arranged as an optical detector comprising at least one sensory element for sensing electromagnetic radiation indicative of actual temperature values.

5. The device as claimed in claim 4, wherein the temperature detector is arranged as a thermal imaging sensor, particularly as a thermal imaging camera.

6. The device as claimed in claim 4, wherein the temperature detector further comprises at least one optical temperature indicator attachable to the subject'"'"'s skin, wherein the at least one optical temperature indicator is capable of exhibiting a property change in response to a change in temperature.

7. The device as claimed in claim 1, wherein the oxygen saturation sensor is arranged as an optical sensor capable of sensing electromagnetic radiation at at least two distinct wavelength portions indicative of blood perfusion in a subject'"'"'s tissue.

8. the device as claimed in claim 7, wherein the oxygen saturation sensor is arranged as an image sensor, particularly as an imaging camera capable of sensing electromagnetic radiation in at least one particular wavelength range.

9. The device as claimed in claim 1, wherein the temperature detector is arranged as a contact sensor attachable to the subject'"'"'s skin.

10. The device as claimed in claim 1, wherein the temperature detector and the oxygen saturation sensor are further capable of operating at sampling rates allowing for detecting inter-cycle variations of blood temperature and blood oxygen saturation.

11. the device as claimed in claim 1, further comprising a clock generator for synchronizing the temperature detector and the oxygen saturation sensor.

12. A system for ventilating a patient, the system comprising

a device according to any of the preceding claims;

and

a patient ventilation interface;

wherein the temperature detector is preferably attached to said patient ventilation interface.

13. A method for unobtrusively determining a blood gas partial pressure in blood in a circulatory system of a subject of interest, comprising the following steps:

non-obtrusively detecting temperature-related measurement values indicative of present intrinsic natural temperature level differences of a subject'"'"'s blood;

non-obtrusively deriving oxygen saturation measurements of the blood of said subject under consideration of said temperature-related measurement values; and

determining a blood gas partial pressure of said monitored subject from said derived oxygen saturation measurements under consideration of present blood temperature level differences of said subject.

14. The method as claimed in claim 13, wherein the step of determining the blood gas partial pressure comprises:

determining pH-representative values attributable to present blood pH-values of the subject, preferably comprising a derivation of the pH-representative values from an oxygen dissociation curve under consideration of changes in said derived oxygen saturation measurements of the blood attributable to detected temperature-related measurement values of the subject'"'"'s blood.

15. A computer program comprising program code means for causing a computer being part of a medical system or device to carry out the steps of the method as claimed in claim 13 when said computer program is carried out on the computer.