System and method of assessment of arousal, pain and stress during anesthesia and sedation
First Claim
1. A method of noninvasively monitoring and controlling stress, pain or arousal states during sedation or anesthesia comprising the steps of:
- acquiring at least one ECG signal from a subject being analyzed;
acquiring an arterial pulse waveform;
processing said at least one ECG signal to identify a pulse initiation fiducial point;
processing said arterial pulse waveform to identify a pulse arrival fidicual point;
calculating the time difference between said pulse initiation fiducial point and said resultant pulse arrival fiducial points of cardiac cycles;
estimating a current PTT from a sequence of said time differences; and
adjusting the administration of analgesia based on clinical interpretation of PTT.
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Accused Products
Abstract
A PTT monitoring system for measuring arousal and responses to stress or pain during sedation or anesthesia. includes ECG electrodes and a PPG probe connected to a computer via signal conditioning and digitizing hardware. Lead I is typically used as the ECG lead while the PPG probe is typically placed on a finger. The ECG and PPG waveforms are continuously analyzed to update and display a current estimate of the subject'"'"'s PPT from heart to hand. For each cardiac cycle, fiducial points are identified to indicate the pulse onset time (via QRS detection in the ECG) and pulse arrival time (via the point of steepest ascent in the PPG). The onset and arrival times for each cardiac cycle are paired, and the time difference is the interval estimate for that beat. An artifact post-processor (e.g., trim-mean filtering) excludes unlikely intervals from entering the averaged, current estimate of PTT. Finally, the current PTT estimate is displayed numerically and the trend of PTT is updated every second. Clinicians may interpret the instantaneous PTT value directly or in context of its recent trend. If there is a rapid decrease in PTT much less than the predetermined baseline value when the patient should be unconscious and free of stress and pain, then supplemental analgesics are administered to bring PTT greater than or equal to such baseline value.
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Citations
16 Claims
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1. A method of noninvasively monitoring and controlling stress, pain or arousal states during sedation or anesthesia comprising the steps of:
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acquiring at least one ECG signal from a subject being analyzed;
acquiring an arterial pulse waveform;
processing said at least one ECG signal to identify a pulse initiation fiducial point;
processing said arterial pulse waveform to identify a pulse arrival fidicual point;
calculating the time difference between said pulse initiation fiducial point and said resultant pulse arrival fiducial points of cardiac cycles;
estimating a current PTT from a sequence of said time differences; and
adjusting the administration of analgesia based on clinical interpretation of PTT. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A system for noninvasively monitoring stress, pain or arousal in a subject comprising:
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at least one ECG lead connected to a subject for acquiring ECG signals from said subject;
probe connected to a subject for acquiring pulse waveform signal from said subject;
a processor for analyzing said ECG and PPG signals to compute an estimate of said subject'"'"'s PTT from the heart of said subject to a location on the body of said subject where said PPG probe is attached and for determining whether the administration of analgesia needs to be adjusted based on said PTT. - View Dependent Claims (14, 15, 16)
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Specification