Monitoring severity and duration of aberrant physiological parameters during a procedure

Abstract

Systems and methods are provided for monitoring a patient during a procedure. A physiological parameter of a patient is monitored during a procedure at an associated sensor. Respective cumulative times are measured for which the monitored physiological parameter of the patient meets each of a plurality of threshold values during the procedure. A risk metric is calculated for the patient, representing an effect of monitored physiological parameter on a patient outcome related to the procedure from the measured cumulative times for which the monitored physiological parameter of the patient met each of the plurality of threshold values.

1 . A method for monitoring a patient under anesthesia during a procedure comprising:
 monitoring a physiological parameter of a patient during a procedure at an associated sensor;   measuring respective cumulative times for which the monitored physiological parameter of the patient meets each of a plurality of threshold values during the procedure;   calculating a risk metric for the patient, representing an effect of monitored physiological parameter on a patient outcome related to the procedure from the measured cumulative times for which the monitored physiological parameter of the patient met each of the plurality of threshold values; and   adjusting a level of anesthesia provided to the patient according to the calculated risk metric, such that further increase in the risk metric is minimized.   
     
     
         2 . The method of  claim 1 , wherein calculating a risk metric for the patient, comprises calculating the risk metric as a linear combination of respective mathematical functions of the measured cumulative times. 
     
     
         3 . The method of  claim 2 , wherein the mathematical function for each cumulative time is a step function, such that the linear combination of the respective mathematical functions of the cumulative times comprises a number of cumulative times that exceed a value associated with their associated step function. 
     
     
         4 . The method of  claim 3 , further comprising calculating a risk index, representing a change in a probability of the patient outcome related to the procedure, as an exponential function of the risk metric. 
     
     
         5 . The method of  claim 3 , further comprising alerting an operator each time a cumulative time exceeds the value associated with its associated step function. 
     
     
         6 . The method of  claim 3 , wherein the values associated with the step functions for the plurality of cumulative times are determined according to at least one biometric parameter of the patient. 
     
     
         7 . The method of  claim 1 , wherein the monitored physiological parameter is a mean arterial blood pressure, and the plurality of threshold values comprise a plurality of mean arterial blood pressure values between forty-five mmHg and seventy-five mmHg. 
     
     
         8 . The method of  claim 6 , wherein the plurality of threshold values comprise each integer value between forty-five mmHg and seventy-five mmHg. 
     
     
         9 . The method of  claim 1 , wherein the calculated risk metric is categorical, and calculating a risk metric for the patient further comprises—classifying a patient into one of a plurality of risk classes to provide the risk metric. 
     
     
         10 . The method of  claim 1 , further comprising alerting an operator each time the calculated risk metric changes. 
     
     
         11 - 16 . (canceled) 
     
     
         17 . A system, implemented on at least one dedicated hardware device, for predicting patient outcomes relating to a procedure comprising:
 a sensor configured to detect a physiological parameter of a patient during the procedure;   a user interface;   a processing assembly configured to compare the detected physiological parameter to a plurality of defined ranges, record respective cumulative times for which the measured physiological parameter deviate from each of the defined ranges, and notify an operator, via an alert at the user interface, each time the cumulative time that the measured physiological parameter exceeds a maximum time associated with a given defined range.   
     
     
         18 . The system of  claim 17 , wherein the sensor is configured to measure a blood pressure of the patient. 
     
     
         19 . (canceled) 
     
     
         20 . A method for detecting hypotensive exposure during anesthesia comprising:
 monitoring a blood pressure of a patient during a procedure at a blood pressure sensor;   measuring respective cumulative times for which the blood pressure of the patient was below each of a plurality of threshold values during the procedure; and   alerting a user, at an associated user device, when any one of the cumulative times exceeds a predetermined exposure limit for its associated threshold value.   
     
     
         21 . The method of  claim 20 , the method further comprising assigning the patient to a course of postsurgical follow-up care according to a number of the plurality of threshold values for which the cumulative time associated with the threshold value exceeds a predetermined exposure limit. 
     
     
         22 . The method of  claim 21 , wherein the plurality of threshold values comprise each integer value between forty-five mmHg and seventy-five mmHg. 
     
     
         23 . The method of  claim 21 , wherein the predetermined exposure limit for each of the plurality of threshold values is selected as a time period associated with a defined progressive increase in a risk of post-procedure morbidity to the patient, such that each predetermined exposure limit that is exceeded represents a same percentage increase in the risk of post-procedure morbidity to the patient. 
     
     
         24 . The method of  claim 9 , the method further comprising assigning the patient to a course of postsurgical follow-up care according to the risk class into which the patient was classified.