BODY-WORN PULSE OXIMETER
First Claim
1. A method for monitoring a patient, comprising:
- (a) measuring a first time-dependent signal by detecting radiation emitted by a first radiation source after it passes through a portion of the patient;
(b) measuring a second time-dependent signal by detecting electrical signals from the patient using at least two electrodes, and processing the electrical signals with an electrical circuit to form the second time-dependent signal;
(c) measuring a time-dependent motion signal with at least one motion sensor;
(d) processing the first and second time-dependent signals to determine a transit time corresponding to a single heartbeat in a collection of heartbeats;
(e) processing multiple transit times, each corresponding to a heartbeat within the collection of heartbeats, with a first algorithm to identify a portion of the first time-dependent signal that may be affected by motion;
(f) analyzing the time-dependent motion signal to estimate if the portion of the first time-dependent signal is affected by motion;
(g) applying a mathematical filter that processes both the portion of the first time-dependent signal and a numerical template representing a pre-determined portion of a time-dependent signal if it is determined that the portion of the first time-dependent signal is affected by motion;
(h) determining a filtered version of at least a portion of the first time-dependent signal with the mathematical filter; and
(i) processing the filtered version of the first time-dependent signal to determine a oxygen saturation value for the patient.
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Accused Products
Abstract
The invention provides a body-worn system that continuously measures pulse oximetry and blood pressure, along with motion, posture, and activity level, from an ambulatory patient. The system features an oximetry probe that comfortably clips to the base of the patient'"'"'s thumb, thereby freeing up their fingers for conventional activities in a hospital, such as reading and eating. The probe secures to the thumb and measures time-dependent signals corresponding to LEDs operating near 660 and 905 nm. Analog versions of these signals pass through a low-profile cable to a wrist-worn transceiver that encloses a processing unit. Also within the wrist-worn transceiver is an accelerometer, a wireless system that sends information through a network to a remote receiver, e.g. a computer located in a central nursing station.
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Citations
16 Claims
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1. A method for monitoring a patient, comprising:
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(a) measuring a first time-dependent signal by detecting radiation emitted by a first radiation source after it passes through a portion of the patient; (b) measuring a second time-dependent signal by detecting electrical signals from the patient using at least two electrodes, and processing the electrical signals with an electrical circuit to form the second time-dependent signal; (c) measuring a time-dependent motion signal with at least one motion sensor; (d) processing the first and second time-dependent signals to determine a transit time corresponding to a single heartbeat in a collection of heartbeats; (e) processing multiple transit times, each corresponding to a heartbeat within the collection of heartbeats, with a first algorithm to identify a portion of the first time-dependent signal that may be affected by motion; (f) analyzing the time-dependent motion signal to estimate if the portion of the first time-dependent signal is affected by motion; (g) applying a mathematical filter that processes both the portion of the first time-dependent signal and a numerical template representing a pre-determined portion of a time-dependent signal if it is determined that the portion of the first time-dependent signal is affected by motion; (h) determining a filtered version of at least a portion of the first time-dependent signal with the mathematical filter; and (i) processing the filtered version of the first time-dependent signal to determine a oxygen saturation value for the patient. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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2. A signal processing method comprising:
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(a) measuring multiple transit times from portions of a first and second time-dependent signal, the first time-dependent signal measured with an optical sensor, and the second time-dependent signal measured with an electrical sensor; (b) measuring a time-dependent motion signal with a motion sensor; (c) collectively processing the multiple transit times and the time-dependent motion signal to determine if the first time-dependent signal is affected by motion; and (d) filtering the first time-dependent signal depending on the processing done in (c).
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3. A method of determining oxygen saturation and blood pressure values for a patient, comprising:
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(a) measuring multiple transit times from portions of a first and second time-dependent signal, the first time-dependent signal measured with an optical sensor, and the second time-dependent signal measured with an electrical sensor; (b) measuring a time-dependent motion signal with a motion sensor; (c) processing the multiple transit times and the time-dependent motion signal to determine if the first time-dependent signal is affected by motion; (d) filtering the first time-dependent signal depending on the processing done in (c) to determine a filtered time-dependent signal; and (e) determining oxygen saturation and blood pressure values for a patient using the filtered time-dependent signal.
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Specification