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US 6,360,114 B1Granted
Pulse oximeter probe-off detector
AssigneeMasimo Corporation
InventorsMohamed K. Diab, Ammar Al Ali
Life of this patent
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AssigneeMasimo Corporation
InventorsMohamed K. Diab, Ammar Al Ali
Estimating the term…
An intelligent, rule-based processor provides signal quality based limits to the 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.
An improvement to a probe-off detector having a signal input, a signal quality input and a probe off output, said signal quality input dependent on a comparison between a sensor output and a physiological signal model, said probe off output providing an indication that said sensor may not be properly attached to a tissue site, said improvement comprising:
An improved method of detecting that a pulse oximetry sensor may not be properly attached to a tissue site by processing a sensor signal, said method comprising the steps of:
Dependencies are inferred from the claim text.