Selecting energy escalation for defibrillation

Abstract

In an aspect, a system for treating a patient in cardiac arrest is described and includes memory, one or more electronic ports for receiving signals from sensors for obtaining indications of an electrocardiogram (ECG) of the patient, one or more sensors for obtaining a transthoracic impedance of the patient, and a patient treatment module executable on one or more processing devices that is configured to generate, from the ECG, transform values that represent magnitudes of two or more frequency components of the ECG, and modify, based on at least one transform value, at least one shock delivery parameter.

What is claimed is: 
     
         1 . A system for treating a patient in cardiac arrest, the system comprising:
 memory;   one or more electronic ports for receiving signals from sensors for obtaining indications of an electrocardiogram (ECG) of the patient;   one or more sensors for obtaining a transthoracic impedance of the patient; and   a patient treatment module executable on one or more processing devices, the patient treatment module configured to:
 generate, from the ECG, transform values that represent magnitudes of two or more frequency components of the ECG, and 
 modify, based on at least one transform value, at least one shock delivery parameter. 
   
     
     
         2 . The system of  claim 1 , wherein the at least one shock delivery parameter is current. 
     
     
         3 . The system of  claim 2 , wherein the current is an average defibrillation current. 
     
     
         4 . The system of  claim 1 , wherein the at least one shock delivery parameter is defibrillation waveform duration. 
     
     
         5 . The system of  claim 1 , wherein the at least one shock delivery parameter is defibrillation waveform rise time. 
     
     
         6 . The system of  claim 1 , wherein the at least one shock delivery parameter is shock energy. 
     
     
         7 . The system of  claim 1 , wherein the at least one shock delivery parameter is defibrillation peak voltage. 
     
     
         8 . The system of  claim 1 , wherein generating the transform values comprises applying one or more Fast Fourier Transforms (FFTs) to data representing the ECG. 
     
     
         9 . The system of  claim 8 , wherein the FFTs comprise vectorized FFTs applied to vectors formed from data obtained by different leads for the ECG. 
     
     
         10 . The system of  claim 8 , wherein generating the transform values comprises one or more amplitude spectrum area calculations applied to the data representing the ECG. 
     
     
         11 . The system of  claim 1 , wherein generating the transform values comprises computing a mathematical transform from a time domain to a frequency domain on a window of data. 
     
     
         12 . The system of  claim 11 , wherein the window is between about one second and about 2 seconds in width. 
     
     
         13 . The system of  claim 11 , wherein the window is a tapered window. 
     
     
         14 . The system of  claim 13 , wherein the tapered window comprises a Tukey window, Hahn window, Blackman Harris window or Flat Top window. 
     
     
         15 . The system of  claim 1 , wherein the system is programmed to automatically charge one or more capacitors to an identified level of energy to be delivered. 
     
     
         16 . The system of  claim 1 , wherein the system is programmed to present to a user an identified level of energy to be delivered, and to permit the user to choose between using the identified level of energy to be delivered or manually selecting a different level of energy to be delivered. 
     
     
         17 . The system of  claim 16 , further comprising a visible, audible, or tactile output mechanism arranged to present, to the user, an indication regarding the identified level of energy to be delivered. 
     
     
         18 . The system of  claim 17 , wherein the indication comprises information about a current level, duration, or associated waveform. 
     
     
         19 . The system of  claim 1 , wherein the patient treatment module is arranged to identify a level of energy to be delivered as a shock to the patient based on a trans-thoracic impedance of the patient and a value derived from a current ECG from the patient. 
     
     
         20 . The system of  claim 1 , wherein the patient treatment module is further arranged to use data representing a current ECG to determine a likelihood of success from delivering a defibrillating shock with one or more capacitors to the patient. 
     
     
         21 . The system of  claim 20 , further comprising an interlock that prevents a user from delivering a shock unless the determined likelihood of success exceeds a determined value. 
     
     
         22 . The system of  claim 1 , further comprising a visible, audible, or tactile output mechanism arranged to present, to a user of the system, an indication regarding the determined likelihood of success from delivering a defibrillating shock with one or more capacitors to the patient. 
     
     
         23 . The system of  claim 1 , wherein the patient treatment module comprises an ECG analyzer for generating an amplitude spectrum area (AMSA) transform value using the transform values. 
     
     
         24 . The system of  claim 1 , wherein generating the transform values includes defining a region for employing one of escalating energy levels for a plurality of shocks or a fixed energy level for a plurality of shocks. 
     
     
         25 . The system of  claim 24 , wherein an AMSA transform value of about 12 mV-Hz defines the region. 
     
     
         26 . A system for treating a patient in cardiac arrest, the system comprising:
 memory;   one or more electronic ports for receiving signals from sensors for obtaining indications of an electrocardiogram (ECG) the patient;   one or more sensors for obtaining a transthoracic impedance of the patient; and   a patient treatment module executable on one or more processing devices, the patient treatment module configured to:
 generate transform values that represent magnitudes of two or more frequency components of the ECG, 
 determine the viability of future therapeutic actions based at least in part on the transform values and the transthoracic impedance, and 
 provide a treatment determination based on the viability determination. 
   
     
     
         27 . The system of  claim 26 , wherein determining the viability of the future therapeutic actions comprises adjusting one or more values derived from the transform values. 
     
     
         28 . The system of  claim 27 , wherein the one or more values derived from the transform values include AMSA values. 
     
     
         29 . The system of  claim 27 , wherein adjusting comprises modifying the one or more values derived from the transform values using a multiplicative factor, linear regression or non-linear regression. 
     
     
         30 . The system of  claim 27 , wherein the adjusting comprises modifying the one or more values derived from the transform values using a table lookup. 
     
     
         31 . The system of  claim 26 , wherein the treatment determination identifies delivering a defibrillating shock to the patient. 
     
     
         32 . The system of  claim 26 , wherein the treatment determination identifies administering cardiopulmonary resuscitation (CPR). 
     
     
         33 . The system of  claim 26 , wherein the treatment determination identifies adjusting a cardiopulmonary resuscitation (CPR) technique. 
     
     
         34 . A system for monitoring the physiological status of a patient in cardiac arrest, the system comprising:
 memory;   one or more electronic ports for receiving signals from sensors for obtaining indications of a vectorcardiograph (VCG) for the patient; and   a patient treatment module executable on one or more processing devices, the patient treatment module configured to:
 generate transform values for a time segment of VCG, 
 wherein the transform values represent magnitudes of two or more frequency components of the VCG, and are indicative of a likelihood of success of a future therapeutic action. 
   
     
     
         35 . The system of  claim 34 , wherein the VCG is represented in a polar coordinate system and the transform is a polar Fourier transform. 
     
     
         36 . The system of  claim 34 , wherein the VCG is represented in a spherical coordinate system and the transform is a spherical Fourier transform. 
     
     
         37 . The system of  claim 34 , wherein the transform is a Hankel transform. 
     
     
         38 . The system of  claim 34 , wherein the transform is a spherical harmonic transform. 
     
     
         39 . One or more machine-readable storage devices having encoded thereon machine readable instructions for causing one or more processors to perform operations comprising:
 receiving signals indicative of an electrocardiogram (ECG) of a patient;   obtaining a transthoracic impedance of the patient;   generating, from the ECG, transform values that represent magnitudes of two or more frequency components of the ECG; and   modifying, based on at least one transform value, at least one shock delivery parameter.   
     
     
         40 . The one or more machine-readable storage devices of  claim 39 , wherein the at least one shock delivery parameter is current. 
     
     
         41 . The one or more machine-readable storage devices of  claim 40 , wherein the current is an average defibrillation current. 
     
     
         42 . The one or more machine-readable storage devices of  claim 39 , wherein the at least one shock delivery parameter is defibrillation waveform duration. 
     
     
         43 . The one or more machine-readable storage devices of  claim 39 , wherein the at least one shock delivery parameter is defibrillation waveform rise time. 
     
     
         44 . The one or more machine-readable storage devices of  claim 39 , wherein the at least one shock delivery parameter is shock energy. 
     
     
         45 . The one or more machine-readable storage devices of  claim 39 , wherein generating the transform values comprises applying one or more Fast Fourier Transforms (FFTs) to data representing the ECG. 
     
     
         46 . The one or more machine-readable storage devices of  claim 45 , wherein the FFTs comprise vectorized FFTs applied to vectors formed from data obtained by different leads for the ECG. 
     
     
         47 . The one or more machine-readable storage devices of  claim 45 , wherein generating the transform values comprises one or more amplitude spectrum area calculations applied to the data representing the ECG. 
     
     
         48 . The one or more machine-readable storage devices of  claim 39 , wherein generating the transform values comprises computing a mathematical transform from a time domain to a frequency domain on a window of data. 
     
     
         49 . The one or more machine-readable storage devices of  claim 48 , wherein the window is between about one second and about 2 seconds in width. 
     
     
         50 . The one or more machine-readable storage devices of  claim 48 , wherein the window is a tapered window. 
     
     
         51 . The one or more machine-readable storage devices of  claim 50 , wherein the tapered window comprises a Tukey window, Hahn window, Blackman Harris window or Flat Top window. 
     
     
         52 . The one or more machine-readable storage devices of  claim 39 , further comprising instructions for automatically charging one or more capacitors to an identified level of energy to be delivered. 
     
     
         53 . The one or more machine-readable storage devices of  claim 39 , further comprising instructions for presenting to a user, an identified level of energy to be delivered, and permitting the user to choose between using the identified level of energy to be delivered or manually selecting a different level of energy to be delivered. 
     
     
         54 . The one or more machine-readable storage devices of  claim 53 , further comprising a visible, audible, or tactile output mechanism arranged to present, to the user, an indication regarding the identified level of energy to be delivered. 
     
     
         55 . The one or more machine-readable storage devices of  claim 54 , wherein the indication comprises information about a current level, duration, or associated waveform. 
     
     
         56 . The one or more machine-readable storage devices of  claim 39 , further comprising instructions for identifying a level of energy to be delivered as a shock to the patient based on a trans-thoracic impedance of the patient and a value derived from a current ECG from the patient. 
     
     
         57 . The one or more machine-readable storage devices of  claim 56 , further comprising instructions for using data representing the current ECG to determine a likelihood of success from delivering a defibrillating shock with one or more capacitors to the patient. 
     
     
         58 . The one or more machine-readable storage devices of  claim 57 , further comprising instructions for implementing an interlock that prevents a user from delivering a shock unless the determined likelihood of success exceeds a determined value. 
     
     
         59 . The one or more machine-readable storage devices of  claim 39 , further comprising instructions for providing a visible, audible, or tactile indication regarding the determined likelihood of success from delivering a defibrillating shock with one or more capacitors to the patient. 
     
     
         60 . The one or more machine-readable storage devices of  claim 39 , further comprising instructions for generating an amplitude spectrum area (AMSA) transform value using the transform values. 
     
     
         61 . The one or more machine-readable storage devices of  claim 39 , wherein generating the transform values includes defining a region for one of employing escalating energy levels for a plurality of shocks or a fixed energy level for a plurality of shocks. 
     
     
         62 . The one or more machine-readable storage devices of  claim 61 , wherein an AMSA transform value of about 12 mV-Hz defines the region. 
     
     
         63 . One or more machine-readable storage devices having encoded thereon machine readable instructions for causing one or more processors to perform operations comprising:
 receiving signals indicative of an electrocardiogram (ECG) of a patient;   obtaining a transthoracic impedance of the patient;   generating transform values that represent magnitudes of two or more frequency components of the ECG;   determining the viability of future therapeutic actions based at least in part on the transform values and the transthoracic impedance; and   providing a treatment determination based on the viability determination.   
     
     
         64 . The one or more machine-readable storage devices of  claim 63 , wherein determining the viability of future therapeutic actions comprises adjusting one or more values derived from the transform values. 
     
     
         65 . The one or more machine-readable storage devices of  claim 64 , wherein the one or more values derived from the transform values include AMSA transform values. 
     
     
         66 . The one or more machine-readable storage devices of  claim 64 , wherein adjusting comprises modifying the one or more values derived from the transform values using a multiplicative factor, linear regression or non-linear regression. 
     
     
         67 . The one or more machine-readable storage devices of  claim 64 , wherein the adjusting comprises modifying the one or more transform values using a table lookup. 
     
     
         68 . The one or more machine-readable storage devices of  claim 63 , wherein the treatment determination identifies delivering a defibrillating shock to the patient. 
     
     
         69 . The one or more machine-readable storage devices of  claim 63 , wherein the treatment determination identifies administering cardiopulmonary resuscitation (CPR). 
     
     
         70 . The one or more machine-readable storage devices of  claim 63 , wherein the treatment determination identifies adjusting a cardiopulmonary resuscitation (CPR) technique. 
     
     
         71 . One or more machine-readable storage devices having encoded thereon machine readable instructions for causing one or more processors to perform operations comprising:
 receiving signals indicative of a vectorcardiograph (VCG) for a patient; and   generating transform values for a time segment of VCG,
 wherein the transform values represent magnitudes of two or more frequency components of the VCG, and are indicative of a likelihood of success of a future therapeutic action. 
   
     
     
         72 . The one or more machine-readable storage devices of  claim 71 , wherein the VCG is represented in a polar coordinate system and the transform is a polar Fourier transform. 
     
     
         73 . The one or more machine-readable storage devices of  claim 71 , wherein the VCG is represented in a spherical coordinate system and the transform is a spherical Fourier transform. 
     
     
         74 . The one or more machine-readable storage devices of  claim 71 , wherein the transform is a spherical Fourier transform or a polar Fourier transform. 
     
     
         75 . The one or more machine-readable storage devices of  claim 71 , wherein the transform is a Hankel transform. 
     
     
         76 . The one or more machine-readable storage devices of  claim 71 , wherein the transform is a spherical harmonic transform.