Adaptive alarm system

Abstract

Systems and electronic processes for reducing electronic alarms in a medical patient monitoring system. For example, a system for reducing electronic alarms can include an optical sensor and one or more hardware processors in electronic communication with the optical sensor. The one or more hardware processors can be programmed to measure oxygen saturation values of a patient over a first period of time, determine if at least one oxygen saturation value obtained over the first period of time exceeds a first alarm threshold, determine whether a first alarm should be triggered based on the determination that the at least one oxygen saturation value obtained over the first period of time exceeds the first alarm threshold, determine a second alarm threshold to be applied during a second period of time subsequent to the first period of time, the second alarm threshold replacing the first alarm threshold.

What is claimed is: 
     
       1. A system for reducing electronic alarms in a medical patient monitoring system, the system comprising:
 an optical sensor configured to transmit optical radiation into a tissue site of a patient and detect attenuated optical radiation indicative of at least one physiological parameter of a patient; and   one or more hardware processors in electronic communication with the optical sensor, the one or more hardware processors configured to:
 measure oxygen saturation values of a patient over a first period of time; 
 determine if at least one oxygen saturation value obtained over the first period of time exceeds a first alarm threshold; 
 determine whether a first alarm should be triggered based on the determination that the at least one oxygen saturation value obtained over the first period of time exceeds the first alarm threshold; 
 determine a second alarm threshold to be applied during a second period of time subsequent to the first period of time, the second alarm threshold replacing the first alarm threshold, the second alarm threshold being determined by:
 comparing at least a first oxygen saturation value obtained during the first time period with a lower limit associated with oxygen saturation; and 
 computing a second alarm threshold based on the comparison where the second alarm threshold is computed to be at a value less than the at least first oxygen saturation value and greater than the lower limit and at an offset from the first oxygen saturation value, wherein the offset is configured to diminish as a difference between the at least first oxygen saturation value and the lower limit diminishes; 
 
 measure oxygen saturation values of a patient over the second period of time to determine at least a second oxygen saturation value; and 
 determine whether a second alarm should be triggered by determining if at least one oxygen saturation value obtained during the second period of time exceeds the second alarm threshold and triggering an alarm if it is determined the second alarm should be triggered. 
   
     
     
       2. The system of  claim 1 , wherein the one or more hardware processors are configured to calculate a first baseline measurement from the measured oxygen saturation values over the first period of time and wherein the at least one oxygen saturation value obtained during the first period of time corresponds to the first baseline measurement. 
     
     
       3. The system of  claim 2 , wherein the one or more hardware processors are configured to calculate a second baseline measurement from the measured oxygen saturation values over the second period of time and wherein the at least one oxygen saturation value obtained during the second period of time corresponds to the second baseline measurement. 
     
     
       4. The system of  claim 1 , wherein the lower limit is predefined and corresponds to a minimum parameter value for oxygen saturation. 
     
     
       5. The system of  claim 1 , wherein the one or more hardware processors are further configured to wait for a time delay prior to the triggering of the second alarm, and wherein the time delay is a function of the second alarm threshold. 
     
     
       6. The system of  claim 5 , wherein the time delay decreases as the difference between the at least first oxygen saturation value and the lower limit diminishes. 
     
     
       7. The system of  claim 1 , wherein the first alarm threshold is predetermined. 
     
     
       8. A system for reducing electronic alarms in a medical patient monitoring system including a pulse oximeter in communication with an optical sensor, the system comprising one or more hardware processors configured to:
 measure oxygen saturation values of a patient over a first period of time;   determine if at least one oxygen saturation value obtained over the first period of time exceeds a first alarm threshold;   determine whether a first alarm should be triggered based on the determination that the at least one oxygen saturation value obtained over the first period of time exceeds the first alarm threshold;   compare at least a first oxygen saturation value obtained during the first time period with a lower limit associated with oxygen saturation;   compute a second alarm threshold based on the comparison;   determine a time delay based on the computed second alarm threshold, wherein the time delay approaches zero as the first oxygen saturation value approaches the lower limit;   measure oxygen saturation values of a patient over the second period of time to determine at least a second oxygen saturation value; and   determine whether a second alarm should be triggered by determining if at least one oxygen saturation value obtained during the second period of time exceeds the second alarm threshold for the time delay and triggering an alarm if it is determined the second alarm should be triggered.   
     
     
       9. The system of  claim 8 , wherein the first alarm threshold is predetermined. 
     
     
       10. The system of  claim 8 , wherein the lower limit is predefined and corresponds to a minimum parameter value for oxygen saturation. 
     
     
       11. The system of  claim 8 , where the second alarm threshold is computed to be at a value less than the at least first oxygen saturation value and greater than the lower limit and at an offset from the first oxygen saturation value, wherein the offset is configured to diminish as a difference between the at least first oxygen saturation value and the lower limit diminishes. 
     
     
       12. An electronic method for reducing electronic alarms in a medical patient monitoring system, the electronic method comprising:
 measuring oxygen saturation values of a patient over a first period of time;   determining if at least one oxygen saturation value determined over the first period of time exceeds a first alarm threshold;   determining whether a first alarm should be triggered based on the determination that at least one oxygen saturation value obtained during the first period of time exceeds the first alarm threshold;   comparing at least a first oxygen saturation value obtained during the first time period with a lower limit associated with oxygen saturation;   computing the second alarm threshold based on the comparison where the second alarm threshold is computed to be at a value less than the at least first oxygen saturation value and greater than the lower limit and at an offset from the first oxygen saturation value, wherein the offset is configured to diminish as a difference between the at least first oxygen saturation value and the lower limit diminishes and wherein the second alarm threshold is configured to be applied during a second period of time subsequent to the first period of time, the second alarm threshold replacing the first alarm threshold;   measuring oxygen saturation values of a patient over the second period of time to determine at least a second oxygen saturation value; and   determining whether a second alarm should be triggered by determining if at least one oxygen saturation value obtained during the second period of time exceeds the second alarm threshold and triggering an alarm if it is determined the second alarm should be triggered.   
     
     
       13. The electronic method of  claim 12 , wherein the one or more hardware processors are configured to calculate a first baseline measurement from the measured oxygen saturation values over the first period of time and wherein the at least one oxygen saturation value obtained during the first period of time corresponds to the first baseline measurement. 
     
     
       14. The electronic method of  claim 13 , wherein the one or more hardware processors are configured to calculate a second baseline measurement from the measured oxygen saturation values over the second period of time and wherein the at least one oxygen saturation value obtained during the second period of time corresponds to the second baseline measurement. 
     
     
       15. The electronic method of  claim 12 , wherein the lower limit is predefined and corresponds to a minimum parameter value for oxygen saturation. 
     
     
       16. The electronic method of  claim 12 , wherein the one or more hardware processors are further configured to wait for a time delay prior to the triggering of the second alarm, and wherein the time delay is a function of the second alarm threshold. 
     
     
       17. The electronic method of  claim 16 , wherein the time delay decreases as the difference between the at least first oxygen saturation value and the lower limit diminishes. 
     
     
       18. The electronic method of  claim 12 , wherein the first alarm threshold is predetermined. 
     
     
       19. A system for reducing electronic alarms in a patient monitoring system, the system comprising:
 an optical sensor configured to transmit optical radiation into a tissue site of a patient and detect attenuated optical radiation indicative of an oxygen saturation of a patient; and   one or more hardware processors in electronic communication with the optical sensor, the one or more hardware processors configured to:
 determine, over a first period of time, whether a first alarm should be triggered based on a first oxygen saturation value obtained in the first period of time crossing a first alarm limit; 
 access a second alarm limit to be applied during a second period of time subsequent to the first period of time, the second alarm limit replacing the first alarm limit, wherein the second alarm limit has a value less than the first oxygen saturation value and greater than a lower limit and at an offset from the first oxygen saturation value, wherein the offset decreases as a difference between the first oxygen saturation value and the lower limit diminishes; 
 determine oxygen saturation values of the patient over the second period of time; and 
 trigger a second alarm based on at least one value of the oxygen saturation values obtained over the second period of time crossing the second alarm limit. 
   
     
     
       20. The system of claim 19, wherein the difference diminishes in response to a decrease in the patient's oxygen saturation until it reaches zero. 
     
     
       21. The system of claim 20, wherein the diminishment is proportional to the difference. 
     
     
       22. The system of claim 20, wherein the diminishment is a stepwise function of discrete diminishment steps. 
     
     
       23. The system of claim 19, wherein the system automatically determines the second alarm limit. 
     
     
       24. The system of claim 19, wherein the system automatically determines the first alarm limit. 
     
     
       25. The system of claim 19, wherein the lower limit is predetermined and corresponds to a minimum parameter value for oxygen saturation. 
     
     
       26. The system of claim 19, wherein the one or more hardware processors are further configured to wait for a time delay prior to triggering of the second alarm, and wherein the time delay is a function of the second alarm limit. 
     
     
       27. An electronic method of reducing electronic alarms in a patient monitoring system, the electronic method comprising:
 determining, over a first period of time, whether a first alarm should be triggered based on a first oxygen saturation value obtained in the first period of time crossing a first alarm limit;   accessing a second alarm limit to be applied during a second period of time subsequent to the first period of time, the second alarm limit replacing the first alarm limit, wherein the second alarm limit has a value less than the first oxygen saturation value and greater than a lower limit and at an offset from the first oxygen saturation value, wherein the offset decreases as a difference between the first oxygen saturation value and the lower limit diminishes;   determining oxygen saturation values of the patient over the second period of time; and   triggerring a second alarm based on at least one value of the oxygen saturation values obtained over the second period of time crossing the second alarm limit.   
     
     
       28. The electronic method of claim 27, wherein the difference diminishes in response to a decrease in the patient's oxygen saturation until it reaches zero. 
     
     
       29. The electronic method of claim 28, wherein the diminishment is proportional to the difference. 
     
     
       30. The electronic method of claim 28, wherein the diminishment is a stepwise function of discrete diminishment steps. 
     
     
       31. The electronic method of claim 27, further comprising automatically determines the second alarm limit. 
     
     
       32. The electronic method of claim 27, further comprising automatically determines the first alarm limit. 
     
     
       33. The electronic method of claim 27, wherein the lower limit is predetermined and corresponds to a minimum parameter value for oxygen saturation. 
     
     
       34. The electronic method of claim 27, further comprising waiting for a time delay prior to triggering of the second alarm, and wherein the time delay is a function of the second alarm limit. 
     
     
       35. A system for reducing electronic alarms in a patient monitoring system, the system comprising one or more hardware processors configured to:
 determine, over a first period of time, whether a first alarm should be triggered based on a first oxygen saturation value obtained in the first period of time crossing a first alarm limit;   access a second alarm limit to be applied during a second period of time subsequent to the first period of time, the second alarm limit replacing the first alarm limit, wherein the second alarm limit has a value less than the first oxygen saturation value and greater than a lower limit and at an offset from the first oxygen saturation value, wherein the offset decreases as a difference between the first oxygen saturation value and the lower limit diminishes;   determine oxygen saturation values of the patient over the second period of time; and   trigger a second alarm based on at least one value of the oxygen saturation values obtained over the second period of time crossing the second alarm limit.