fig1 illustrates a physiological assessment system 100 that advantageously monitors the nonlinear dynamics of one or more physiological parameters 122 so as to provide a physiological assessment 132 of a living organism . the physiological assessment system 100 has one or more sensors 110 capable of responding to a living organism so as to provide sensor signals 112 to one or more physiological parameter processors 120 . the physiological parameter processors 120 provide measured parameters 122 derived from the sensor signals 112 . a nonlinear dynamics processor 130 analyzes the dynamics of the measured parameters 122 so as to provide a physiological assessment 132 of the living organism . a sensor ( s ) 110 may be a pulse oximetry sensor , a blood pressure transducer , ecg or eeg electrodes or a capnometer , or a combination of these , to name a few . the physiological parameter processor ( s ) 120 , accordingly , may be a pulse oximeter , a blood pressure monitor , an ecg monitor , an eeg monitor , a co 2 monitor or a multi - parameter patient monitor , or a combination of these , to name a few . likewise , the measured parameters 122 may be , as examples , oxygen saturation , pulse rate , perfusion index , blood glucose , blood pressure and etco 2 among others . the nonlinear dynamics processor 130 can be hardware , software or a combination that analyzes , for example , the variability of the measured parameters 122 . the physiological assessment 132 may be a numerical readout , message or other visual display or an alarm or other audible indication , or a combination of these . the physiological assessment 132 may assist in the determination of illness severity , wellness , or depth of sedation , to name a few ; may provide information helpful for triage in emergency , hospital or surgical environments , for example ; or may help in the prediction of , for instance , recovery time , length of hospitalization or medical costs . fig2 illustrates one embodiment of a physiological assessment system 200 having a pulse oximeter 210 , a data storage 220 , a variability analyzer 230 and a statistics interpreter 240 . the pulse oximeter 210 measures parameters 212 such as perfusion index ( pi ) or pulse rate ( pr ) or a combination of pi and pr . the data storage 220 compiles a trend of the parameters 212 so as to create a data record 224 . the data record length ( t ) is set by a predetermined storage interval input 222 . the variability analyzer 230 processes the data record 224 so as to provide data statistics 232 . in a particular embodiment , the variability analyzer 230 is a chaos data analyzer ( cda - pro ) available from the academic software library , north carolina state university , raleigh , n . c . the cda - pro performs various tests for detecting hidden determinism in a seemingly random time series , such as the probability distribution , power spectrum , lyapunov exponent , and various measures of the fractal dimension . the statistics interpreter 240 evaluates the data statistics 232 to determine if variability is in a normal or abnormal range and provides an illness severity indicator 244 accordingly . a predetermined normality range input 242 sets this range . the illness severity indicator 244 may be displayed 250 or may trigger an alarm 260 or both . in an alternative embodiment , the range input 242 may specify multiple ranges , which may include one or more of variability above a normal level indicating illness , variability within a normal range , variability within an indeterminate range , and variability below a normal range indicating illness . the range input 242 may also be a threshold or cutoff between normal and abnormal variability . in another embodiment , pr variability may be used as an early predictor of a return to health , and pi variability may be used as an early predictor of the onset of illness . in a particular embodiment , the pulse oximeter 210 incorporates the data storage 220 , variability analyzer 230 and statistics interpreter 240 . the display 250 is a scaled readout on a pulse oximeter 210 showing pi variance on a relative scale having a gauge of maximum and minimum ranges . an alarm 260 is configured to sound when pi variance drops below a predetermined level . fig3 illustrates a physiological assessment method 300 wherein physiological parameters are iteratively measured 310 and recorded as a time series 320 . the physiological parameters may be , for example , perfusion index or pulse rate or both . nonlinear dynamics of the time series are calculated 330 . these calculations may be based upon chaos data analysis . the nonlinear dynamics are evaluated with respect to predetermined criteria 340 so as to provide a physiological assessment 350 . in one embodiment , the nonlinear dynamics may provided a measure of variability of the physiological parameter or parameters , which may be compared to a range of normal or abnormal variability or , alternatively , a threshold or cutoff value or variability so as to assess illness severity or depth of sedation , for example . a physiological assessment system has been disclosed in detail in connection with various embodiments . these embodiments are disclosed by way of examples only and are not to limit the scope of the claims that follow . one of ordinary skill in art will appreciate many variations and modifications .
a physiological assessment system comprises a sensor and first and second processors . the sensor is adapted to generate a signal responsive to a living organism . the first processor is configured to derive a measured parameter from the sensor signal . the second processor is configured to analyze nonlinear dynamics of the measured parameter so as to provide a physiological assessment of the living organism .