Methods and Systems for Determining Whether to Trigger an Alarm

Abstract

According to embodiment, systems and methods for processing a physiological measurement and generating alarms based on the measurement are provided. Multiple features of a single physiological measurement may be concurrently monitored to generate alarms. One or more of the features may be based on a trend of the physiological measurement. One or more of the features may be based on a wavelet transform of the physiological measurement. Different features may be used in different combinations to lower the percentage of false alarms while still recognizing valid alarm events.

What is claimed is: 
     
         1 . A method for determining whether to trigger an alarm, the method comprising:
 using a processor for:
 receiving an SpO 2  signal; 
 determining at least one feature of the SpO 2  signal; 
 performing a wavelet transform of the SpO 2  signal to generate a scalogram; 
 determining at least one feature of the scalogram; and 
 determining whether to trigger an alarm based at least in part on the at least one feature of the SpO 2  signal and the at least one feature of the scalogram. 
   
     
     
         2 . The method of  claim 1 , wherein the at least one feature of the scalogram comprises signal quality. 
     
     
         3 . The method of  claim 1 , wherein the at least one feature of the scalogram comprises a feature indicative of a probe condition. 
     
     
         4 . The method of  claim 1 , wherein the at least one feature of the scalogram comprises a moving average of the scalogram. 
     
     
         5 . The method of  claim 1 , wherein the at least one feature of the scalogram comprises a slope of the scalogram. 
     
     
         6 . The method of  claim 1 , wherein the feature of the SpO 2  signal comprises a moving average of the SpO 2  signal. 
     
     
         7 . The method of  claim 1 , wherein the feature of the SpO 2  signal comprises a value of the SpO 2  signal. 
     
     
         8 . The method of  claim 1 , wherein the feature of the SpO 2  signal comprises a slope of the SpO 2  signal. 
     
     
         9 . The method of  claim 1 , further comprising determining whether the at least one feature of the SpO 2  signal is below a threshold. 
     
     
         10 . The method of  claim 1 , further comprising generating an alarm based at least in part on the determining whether to trigger an alarm. 
     
     
         11 . A system capable of determining whether to trigger an alarm, the system comprising:
 an SpO 2  signal generator coupled to the sensor and capable of generating an SpO 2  signal based at least in part on a PPG signal;   a wavelet transform generator coupled to the SpO 2  signal generator and capable of performing a wavelet transform of the SpO 2  signal to generate a scalogram;   at least a first feature analyzer coupled to the SpO 2  signal generator capable of determining at least one feature of the SpO 2  signal and providing an output;   at least a second feature analyzer coupled to the wavelet transform generator capable of determining at least one feature of the scalogram and providing an output; and   an alarm generator coupled at least to the outputs of the first feature analyzer and the second feature analyzer and capable of triggering an alarm based at least in part on the outputs.   
     
     
         12 . The system of  claim 11 , further comprising a sensor capable of generating the photoplethysmograph (PPG) signal; and 
     
     
         13 . The system of  claim 11 , wherein the at least one feature of the scalogram comprises at least one of signal quality and probe condition. 
     
     
         14 . The system of  claim 11 , wherein the at least one feature of the scalogram comprises a moving average of the scalogram. 
     
     
         15 . The system of  claim 11 , wherein the at least one feature of the scalogram comprises a slope of the scalogram. 
     
     
         16 . The system of  claim 11 , wherein the at least one feature of the SpO 2  signal comprises a moving average of the SpO 2  signal. 
     
     
         17 . The system of  claim 11 , wherein the at least one feature of the SpO 2  signal comprises a value of the SpO 2  signal. 
     
     
         18 . The system of  claim 11 , wherein the at least one feature of the SpO 2  signal comprises a slope of the SpO 2  signal. 
     
     
         19 . Non-transitory computer-readable medium for use in determining whether to trigger an alarm, the non-transitory computer-readable medium having computer program instructions recorded thereon for:
 determining at least one feature of the SpO 2  signal;   performing a wavelet transform of the SpO 2  signal to generate a scalogram;   determining at least one feature of the scalogram; and   determining whether to trigger an alarm based at least in part on the at least one feature of the SpO 2  signal and the at least one feature of the scalogram.   
     
     
         20 . The non-transitory computer-readable medium of  claim 19 , wherein:
 the at least one feature of the SpO 2  signal is selected from the group consisting of slope, value, or moving average; and   the at least one feature of the scalogram is selected from the group consisting of signal quality, probe condition, or moving average.