Perfusion index smoother
An embodiment of the present disclosure seeks to smooth a perfusion index measurement through use of a baseline perfusion index measurement and/or through the use of multiple PI calculations. The combination of the baseline perfusion index measurement reduces an error between a calculated measurement of PI and actual conditions.
1. A method of determining an indication of a physiological condition using data responsive to intensity signals acquired from a detector capable of detecting light attenuated by body tissue, the method comprising:
determining one or more indications of pulse information from data responsive to intensity signals acquired from a detector capable of detecting light attenuated by body tissue;
determining a first indication of amplitude data on a pulse by pulse basis based on the one or more indications of pulse information;
determining a second indication of amplitude data for a combination of pulses based on the one or more indications of pulse information;
determining a final indication of amplitude data based on the first and second indications, wherein the determining a final indication comprises selecting a lowest indication of amplitude from the first and second indications, averaging the first and second indications of amplitude, or using a statistical analysis of the first and second indications of amplitude; and
outputting the final indication as an indication of perfusion index.
2. The method of claim 1 , wherein the determining the final indication further comprises using a signal quality indication.
3. The method of claim 1 , wherein the determining the final indication comprises selecting the lowest indication of amplitude.
4. The method of claim 1 , wherein the determining the final indication comprises averaging the first and second indications of amplitude.
5. The method of claim 1 , wherein the determining the final indication comprises using the statistical analysis of the first and second indications of amplitude.
6. The method of claim 1 , wherein the combination comprises a statistical combination of pulses.
7. The method of claim 1 , wherein the combination comprises a maximum and minimum amplitude of a plurality of pulses.
8. A method of determining an indication of perfusion index in a patient monitor, the method comprising:
receiving pleth data;
calculating at least two indications of perfusion index based on the pleth data using at least two different calculation techniques; and
determining a final indication of perfusion index based on the at least two indications of perfusion index, the final indication determined based on a signal quality, the lowest determined value of the at least two indications of perfusion index, an average of the at least two indications of perfusion index or a statistical analysis of the at least two indications of perfusion index;
wherein a first of said calculation techniques performs analysis based on a pulse by pulse basis and a second of said calculation techniques performs analysis based on a combination of pulses.
9. The method of claim 8 , wherein the determining the final indication further comprises using the signal quality indication.
10. The method of claim 8 , wherein the determining the final indication comprises using amplitude data.
11. The method of claim 10 , wherein the amplitude data comprises a maximum and minimum amplitude of at least one pulse.
12. The method of claim 10 , wherein the amplitude data comprises a maximum and minimum amplitude of a plurality of pulses.
13. The method of claim 8 , wherein the determining a final indication comprises selecting the lowest indication of amplitude.
14. The method of claim 8 , wherein the determining a final indication further comprises averaging a first and a second indications of amplitude.
15. The method of claim 8 , wherein the determining a final indication comprises using the statistical analysis of the at least two indications of perfusion index.