PULSE OXIMETER PROBE-OFF DETECTOR
First Claim
1. In a patient monitor configured to obtain signals responsive to physiological parameters of a monitored patient, a detector for determining when a physiological sensor may not be properly attached to said monitored patient with respect to a measurement site, the detector comprising:
- a limit selector configured to output a signal strength limit in response to a sensitivity mode; and
logic configured to indicate that a sensor not properly attached condition exists based on a comparison of a signal strength of one or more signals indicative of one or more physiological parameters and the signal strength limit.
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Accused Products
Abstract
A processor provides signal quality based limits to a signal strength operating region of a pulse oximeter. These limits are superimposed on the typical gain dependent signal strength limits. If a sensor signal appears physiologically generated, the pulse oximeter is allowed to operate with minimal signal strength, maximizing low perfusion performance. If a sensor signal is potentially due to a signal induced by a dislodged sensor, signal strength requirements are raised. Thus, signal quality limitations enhance probe off detection without significantly impacting low perfusion performance. One signal quality measure used is pulse rate density, which defines the percentage of time physiologically acceptable pulses are occurring. If the detected signal contains a significant percentage of unacceptable pulses, the minimum required signal strength is raised proportionately. Another signal quality measure used in conjunction with pulse rate density is energy ratio, computed as the percentage of total energy contained in the pulse rate fundamental and associated harmonics.
96 Citations
20 Claims
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1. In a patient monitor configured to obtain signals responsive to physiological parameters of a monitored patient, a detector for determining when a physiological sensor may not be properly attached to said monitored patient with respect to a measurement site, the detector comprising:
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a limit selector configured to output a signal strength limit in response to a sensitivity mode; and logic configured to indicate that a sensor not properly attached condition exists based on a comparison of a signal strength of one or more signals indicative of one or more physiological parameters and the signal strength limit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a patient monitor configured to obtain signals responsive to physiological parameters of a monitored patient, a method for determining when a physiological sensor may not be properly attached to said monitored patient with respect to a measurement site, the method comprising:
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receiving one or more setting signals indicative of one or more selectable settings; determining a signal strength limit based upon the one or more setting signals; determining a signal strength based upon one or more sensor signals wherein said one or more sensor signals are indicative of one or more physiological parameters; and determining whether a sensor not properly attached condition exists based upon the sensor strength and the signal strength. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification