Plethysmograph variability processor

A plethysmograph variability processing system comprising:

• an optical sensor that transmits multiple wavelengths of optical radiation into a tissue site, detects the optical radiation after attenuation by pulsatile blood flowing within the tissue site, and generates a sensor signal responsive to the detected optical radiation;
• a patient monitor that demodulates the sensor signal so as to generate a plurality of plethysmograph channels;
• a digital signal processor (DSP) within the patient monitor that inputs at least one of the plethysmograph channels and outputs a plethysmograph variability (PV) parameter accordingly;
• a PV process that executes on the DSP so as to process the at least one plethysmograph channel and derive the PV parameter;
• and
• a patient monitor output that is responsive to the PV parameter.

A plethysmograph variability method comprising:

• inputting at least one of a plurality of plethysmograph channels measuring a plurality of plethysmograph values from the input;
• defining a plurality of windows each encompassing a unique time interval of the plethysmograph values;
• calculating a plurality of variability values, each of the variability values derived from the plethysmograph values encompassed in a unique one of the windows;
• defining a second plurality of windows each encompassing a unique time interval of the variability values;
• calculating a plurality of parameter values, each of the parameter values derived from the variability values encompassed in a unique one of the second windows;
• and
• outputting the parameter values.

A plethysmograph variability processing system having a sensor that transmits multiple wavelengths of optical radiation into a tissue site and that detects the optical radiation after attenuation by pulsatile blood flow within a tissue site so as to provide a plethysmograph input to a digital signal processor (DSP), the input selected from a plurality of channels corresponding to the multiple wavelengths, the DSP executes instructions for deriving plethysmograph variability from the plethysmograph, comprising:

• a plethysmograph input;
• a measuring means for generating plethysmograph values from the plethysmograph input according to predefined plethysmograph features;
• a calculation means for deriving variability values from the plethysmograph values;
• and
• a reduction means for deriving a plethysmograph variability (PV) parameter from the plethysmograph values.