Pulse oximeter probe-off detector
First Claim
1. A patient monitor configured to obtain signals responsive to physiological parameters of a monitored patient and determine when a physiological sensor may not be properly attached to said monitored patient with respect to a measurement site, the patient monitor comprising:
- one or more processors configured to;
receive a sensitivity mode setting;
determine a signal strength limit based at least in part on the sensitivity mode setting;
determine a signal strength of one or more signals indicative of one or more physiological parameters of a monitored patient, wherein the one or more signals comprise a plurality of pulses, each pulse comprising a plurality of pulse features;
perform one or more checks on one or more pulse features to determine one or more physiologically acceptable pulses from the plurality of pulses, wherein the one or more features include at least one of pulse starting point, pulse period, or pulse signal strength;
determine a pulse rate density indicative of a percentage of time physiologically acceptable pulses occur;
determine a sensor not properly attached condition exists when the signal strength and the pulse rate density fall within a probe off region, wherein the probe off region is associated with the signal strength limit and wherein the probe off region corresponds to operating conditions outside an acceptable operating range; and
indicate an alarm condition responsive to a determination that the sensor not properly attached condition exists.
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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.
699 Citations
23 Claims
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1. A patient monitor configured to obtain signals responsive to physiological parameters of a monitored patient and determine when a physiological sensor may not be properly attached to said monitored patient with respect to a measurement site, the patient monitor comprising:
one or more processors configured to; receive a sensitivity mode setting; determine a signal strength limit based at least in part on the sensitivity mode setting; determine a signal strength of one or more signals indicative of one or more physiological parameters of a monitored patient, wherein the one or more signals comprise a plurality of pulses, each pulse comprising a plurality of pulse features; perform one or more checks on one or more pulse features to determine one or more physiologically acceptable pulses from the plurality of pulses, wherein the one or more features include at least one of pulse starting point, pulse period, or pulse signal strength; determine a pulse rate density indicative of a percentage of time physiologically acceptable pulses occur; determine a sensor not properly attached condition exists when the signal strength and the pulse rate density fall within a probe off region, wherein the probe off region is associated with the signal strength limit and wherein the probe off region corresponds to operating conditions outside an acceptable operating range; and indicate an alarm condition responsive to a determination that the sensor not properly attached condition exists. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. 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 from the one or more setting signals; determining a signal strength of one or more sensor signals indicative of one or more physiological parameters of a monitored patient, wherein the one or more signals comprise a plurality of pulses; performing one or more checks on one or more pulse features to determine one or more physiologically acceptable pulses from the plurality of pulses, wherein the one or more features include at least one of pulse starting point, pulse period, or pulse signal strength; determining a pulse rate density indicative of a percentage of time physiologically acceptable pulses occur; determining a sensor not properly attached condition exists when the signal strength and the pulse rate density fall within a probe off region, wherein the probe off region is associated with the signal strength limit and wherein the probe off region corresponds to operating conditions outside an acceptable operating range; and indicating an alarm condition responsive to a determination that the sensor not properly attached condition exists. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification