Device and method for transcutaneous determination of blood gases
The device for the transcutaneous determination of blood gases including a transcutaneous sensor for the measurement of at least one of the parameters of skin carbon dioxide partial pressure (PsCO2) and skin oxygen partial pressure (PsO2) includes at least one sensor for the measurement of the tissue blood flow (F) local with respect to the transcutaneous sensor, and includes a device for the calculation of at least one of the parameters of transcutaneous carbon dioxide partial pressure (tcpCO2) and transcutaneous oxygen partial pressure (tcpO2) from the measured skin carbon dioxide partial pressure (PsCO2) or the measured skin oxygen partial pressure (PsO2), with a factor dependent on the local tissue blood flow (F) being taken into account in the calculation of at least one of the parameters of transcutaneous carbon dioxide partial pressure (tcpCO2) and transcutaneous oxygen partial pressure (tcpO2).
1. A device for a transcutaneous determination of blood gases comprising:
a transcutaneous sensor for a measurement of at least one of the parameters of skin carbon dioxide partial pressure (PsC02) and skin oxygen partial pressure (Ps02), at least one sensor for a measurement of a tissue blood flow (F) local with respect to the transcutaneous sensor, and a device for the calculation of at least one of the parameters of transcutaneous carbon dioxide partial pressure (tcpC02) and transcutaneous oxygen partial pressure (tcp02) from the measured skin carbon dioxide partial pressure (PsC02) or the measured skin oxygen partial pressure (Ps02) respectively, with a factor dependent on the local tissue blood flow (F) being taken into account in a calculation of at least one of the parameters of transcutaneous carbon dioxide partial pressure (tcpC02) and transcutaneous oxygen partial pressure (tcp02),
wherein the determination of the transcutaneous carbon dioxide partial pressure (tcpC02) takes place in accordance with the equation:
tcp
CO
2
(
Tr
,
F
)
=
Ps
CO
2
(
Ts
)
10
(
Ts
-
Tr
)
×
A
-
Ms
(
F
)
while taking account of the local tissue blood flow (F).
2. A device in accordance with claim 1 , wherein the determination of the transcutaneous carbon dioxide partial pressure (tcpCO2) takes place in accordance with the equation:
tcp
CO
2
(
Tr
,
F
)
=
Ps
CO
2
(
Ts
)
10
(
Ts
-
Tr
)
×
A
-
Ms
(
Ts
,
F
)
while additionally taking account of the local temperature (Ts).
3. A device in accordance with claim 1 , wherein the determination of the transcutaneous oxygen partial pressure (tcpO2) takes place in accordance with the equation tcpO2(Tr,F)=Corr(F)*PsO2(Ts) while additionally taking account of the local tissue blood flow (F).
4. A device in accordance with claim 1 , wherein the determination of the transcutaneous oxygen partial pressure (tcpO2) takes place in accordance with the equation tcpO2(Tr,F)=Corr(Tr,Ts,F)*PsO2(Ts) while taking account of the local temperature (Ts).
5. A device in accordance with claim 1 , wherein the at least one sensor for the measurement of the local tissue blood flow (F) is arranged in the same housing as the transcutaneous sensor.
6. A device in accordance with claim 1 , wherein the at least one sensor for the measurement of the local tissue blood flow (F) are configured such that they measure the local tissue blood flow (F) beneath the contact surface of the transcutaneous sensor.
7. A device in accordance with claim 1 , wherein the at least one sensor for the measurement of the local tissue blood flow (F) detect a region of up to 4 cm distance from the contact surface of the transcutaneous sensor.
8. A device in accordance with claim 1 , wherein the at least one sensor for the measurement of the local tissue blood flow (F) are part of a (photo)plethysmographic measurement system.
9. A device in accordance with claim 8 wherein the (photo)plethysmographic measurement system is selected from the group consisting of a pulse spectroscopic and a pulse oximetric measurement system.
10. A device in accordance with claim 1 , wherein the at least one sensor for the measurement of the local tissue blood flow (F) are part of a heating device which keeps the temperature of the contact surface constant, with the power supplied to the heating device being a measure for the tissue blood flow (F).
11. A device in accordance with claim 1 , wherein the at least one sensor for the measurement of the local tissue blood flow (F) are configured as acoustic sensors or as light sensors and form part of a Doppler measurement system.
12. A device in accordance with claim 1 , wherein the at least one sensor for the measurement of the local tissue blood flow (F) is configured as a laser sensor, and forms part of a Doppler measurement system.
13. A method for transcutaneous blood gas monitoring, comprising:
detecting at least one of the parameters of skin carbon dioxide partial pressure (PsCO2) and skin oxygen partial pressure (PsO2), and detecting a local tissue blood flow (F), and calculating at least one of the parameters of transcutaneous carbon dioxide partial pressure (tcpCO2) and transcutaneous oxygen partial pressure (tcpO2) from the measured skin carbon dioxide partial pressure (PsCO2) or the measured skin oxygen partial pressure (PsO2), wherein the local tissue blood flow (F) is taken into account in the calculation of at least one of the parameters of transcutaneous carbon dioxide partial pressure (tcpCO2) and transcutaneous oxygen partial pressure (tcpO2),
wherein the transcutaneous carbon dioxide partial pressure (tcpCO2) is calculated as a function of the tissue blood flow (F) in accordance with the equation
tcp
CO
2
(
Tr
,
F
)
=
Ps
CO
2
(
Ts
)
10
(
Ts
-
Tr
)
×
A
-
Ms
(
F
)
.
14. A method in accordance with claim 13 , wherein the transcutaneous carbon dioxide partial pressure (tcpCO2) is additionally calculated as a function of the local temperature (Ts) in accordance with the equation
tcp
CO
2
(
Tr
,
F
)
=
Ps
CO
2
(
Ts
)
10
(
Ts
-
Tr
)
×
A
-
Ms
(
Ts
,
F
)
.
15. A method in accordance with claim 13 , wherein the transcutaneous oxygen partial pressure (tcpO2) is calculated as a function of the tissue blood flow (F) in accordance with the equation tcpO2(Tr,F)=Corr(Tr,Ts,F)*PsO2(Ts).
16. A method in accordance with claim 15 , wherein the transcutaneous oxygen partial pressure (tcpO2) is additionally calculated as a function of the local temperature (Ts) in accordance with the equation tcpO2(Tr,F)=Corr(Tr,Ts,F)*PsO2(Ts).
17. A method in accordance with claim 13 , wherein a transcutaneous sensor has a contact surface; and the local tissue blood flow (F) is measured within the region determined by the contact surface.
18. A method in accordance with claim 13 , wherein a transcutaneous sensor has a contact surface; and the local tissue blood flow (F) is measured within a region of up to 4 cm, and preferably within a region of up to 2 cm, distance from the contact surface of the transcutaneous sensor.
19. A method in accordance with claim 13 , wherein the local tissue blood flow (F) is determined using a (photo)plethysmographic measurement system.
20. A method in accordance with claim 13 , wherein the local tissue blood flow (F) is determined using a heating device which keeps the temperature of the contact surface constant, with the power supplied to the beating device being a measure for the tissue blood flow (F).
21. A method in accordance with claim 13 , wherein the local tissue blood flow (F) is determined using acoustic sensors or light sensors which are part of a Doppler scan system.
22. A method in accordance with claim 13 , wherein the local tissue blood flow (F) is determined using a pulse spectroscopic or a pulse oximetric measurement system.
23. A method in accordance with claim 13 , wherein the local tissue blood flow (F) is determined using laser sensors which are part of a Doppler scan system.
24. A method comprising using a sensor for a transcutaneous determination of blood gases, the sensor comprising a transcutaneous sensor for a measurement of a skin carbon dioxide partial pressure (PsCO2) and comprising sensor for a pulse spectroscopic or pulse oximetric measurement of the arterial oxygen saturation (SpO2), the method comprising determining a local tissue blood flow (F) using the sensor for the pulse spectroscopic or pulse oximetric measurement mid calculating the transcutaneous carbon dioxide partial pressure (tcpCO2) from the measured skin carbon dioxide partial pressure (PsCO2) taking into account the local tissue blood flow (F) in accordance with the equation:
tcp
CO
2
(
Tr
,
F
)
=
Ps
CO
2
(
Ts
)
10
(
Ts
-
Tr
)
×
A
-
Ms
(
F
)
.
25. A method comprising using a sensor for a transcutaneous determination of blood gases, the sensor comprising a transcutaneous sensor for a measurement of the skin carbon dioxide partial pressure (PsCO2), the sensor comprising a sensor for a pulse spectroscopic or pulse oximetric measurement of an arterial oxygen saturation (SpO2) and comprising a heating device, the method comprising calculating local tissue blood flow (F) wherein at least the pulse spectroscopic or pulse oximetric measurement or at least the heating device is taken into account for a determination of the local tissue blood flow (F) and comprising calculating transcutaneous carbon dioxide partial pressure (tcpC02) from the measured skin carbon dioxide partial pressure (PsC02) taking into account the local tissue blood flow (F), wherein the at least one sensor for the measurement of the local tissue blood flow (F) detects a region of up to 2 cm distance from a contact surface of the transcutaneous sensor.