Using PH and SMO2 from a spectral sensor as an indication of subject down time
Inventors
Freeman, Gary A. • Herken, Ulrich • Kaufman, Christopher L. • Silver, Annemarie Elizabeth
Assignees
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Publication Number
US-12350012-B2
Publication Date
2025-07-08
Expiration Date
Abstract
Embodiments of the present disclosure relate generally to the use of spectral sensors during a cardiac arrest event. More specifically, the present disclosure relates to the use of spectral sensors for measuring changes in pH and muscle oxygen saturation to estimate subject down time and evaluating the effectiveness of the clinical treatment administered during a cardiac arrest event. Given the narrow window of time in which emergency treatment must be administered, as well as the lack of information concerning the subject's condition, there is a need for a fast and accurate method of estimating the onset of the cardiac arrest emergency and evaluating the effectiveness of the emergency treatment being administered.
Core Innovation
A patient monitoring system assists treatment of a patient experiencing a cardiac arrest event by using an external defibrillator to administer defibrillation therapy and by using a skin-placed spectral sensor assembly to obtain spectroscopic data continuously during a period of time. The spectral sensor assembly includes at least one of a muscle oxygen saturation sensor, a pH sensor, a blood hematocrit sensor, a carbon dioxide sensor, or a pulse oximetry sensor. The system presents physiological information to a user via a display.
The system processes the spectroscopic data to determine tissue oxygen saturation and compares the determined tissue oxygen saturation to a mathematical model. The mathematical model represents a plurality of tissue oxygen saturation measurements obtained from a group of subjects having similar demographics and similar physiological characteristics as the patient. Based on the comparison, the system determines that the patient experienced the cardiac arrest event at a first time and determines an elapsed time since the first time.
Using the elapsed time, the system determines whether to administer the defibrillation therapy using the external defibrillator or to administer cardiopulmonary resuscitation (CPR) without administering the defibrillation therapy, and presents an indication of the elapsed time and the therapy selection. In addition, the system determines, based on the spectroscopic data, an effectiveness of a treatment of the patient during the period of time and presents, using the display, an indication of the effectiveness of the treatment.
Claims Coverage
The provided claim set contains one independent claim. The independent claim covers continuous skin-placed spectroscopic sensing, model-based estimation of elapsed time since a cardiac arrest event, decision support for defibrillation therapy versus CPR without defibrillation, and display of treatment effectiveness during the monitored period.
Continuous skin-placed spectroscopic sensing during cardiac arrest
A spectral sensor assembly comprising at least one of a muscle oxygen saturation sensor, a pH sensor, a blood hematocrit sensor, a carbon dioxide sensor, or a pulse oximetry sensor, configured to be placed on a skin of the patient and configured to obtain spectroscopic data continuously during a period of time.
Subject-based mathematical model comparison to determine event time
Process the spectroscopic data to determine tissue oxygen saturation of the patient, compare the determined tissue oxygen saturation to a mathematical model representing a plurality of tissue oxygen saturation measurements obtained from a group of subjects having similar demographics and similar physiological characteristics as the patient, determine that the patient experienced the cardiac arrest event at a first time, and determine an elapsed time since the first time.
Elapsed-time-based decision between defibrillation therapy and CPR
Determine, based on the elapsed time, whether to administer the defibrillation therapy on the patient using the external defibrillator or administer cardiopulmonary resuscitation (CPR) on the patient without administering the defibrillation therapy, and present an indication whether to administer the defibrillation therapy or administer CPR without administering the defibrillation therapy.
Displayed treatment effectiveness based on spectroscopic data
Determine, based on the spectroscopic data, an effectiveness of a treatment of the patient during the period of time, and present, using the display, an indication of the effectiveness of the treatment including at least one of an indication to continue administering CPR or an indication to discontinue administering CPR and administer an alternative treatment.
The independent claim centers on continuous skin-placed spectroscopic sensing, deriving tissue oxygen saturation and comparing it to a subject-based mathematical model to estimate elapsed time since the cardiac arrest event, using that elapsed time to decide between defibrillation therapy and CPR without defibrillation, and displaying treatment effectiveness over the monitored period.
Stated Advantages
Provides an indication of the elapsed time since the cardiac arrest event to a user.
Supports determining whether to administer defibrillation therapy or administer CPR without administering defibrillation therapy based on elapsed time.
Provides an indication of treatment effectiveness during the period of time, including guidance to continue CPR or discontinue CPR and administer an alternative treatment.
Documented Applications
Assisting treatment of a patient experiencing a cardiac arrest event by monitoring spectroscopic data, estimating elapsed time since onset, selecting defibrillation therapy versus CPR without defibrillation, and indicating treatment effectiveness during CPR and/or alternative treatment.
A three-phase cardiac arrest decision framework using estimated elapsed time and associated pH/SmO2 cutoff values to trigger different treatment protocols.
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