Pulse Oximeter Alarm Threshold Adaptation
Solution Overview
Problem
Pulse oximeters generate nuisance alarms due to noise and inaccuracies in oxygen saturation (SpO2) and pulse rate measurements, leading to false alerts and decreased reliability.
Innovation Solution
The system calculates a probability distribution and accuracy of SpO2 measurements, adjusting alarm thresholds and delaying alarms based on these metrics to reduce false alarms, incorporating modules for oxygen saturation estimation, accuracy calculation, and alarm generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional alarm thresholds are used without considering measurement accuracy, then alarm responsiveness is improved, but false alarm rate increases
Solution Approach 1:
The patent changes the alarm threshold from a fixed value to a dynamic value that adapts based on measurement accuracy. The alarm threshold is adjusted according to the calculated accuracy of the SpO2 measurement, allowing the system to maintain high reliability by accounting for measurement uncertainty while avoiding false alarms when accuracy is low
Solution Approach 2:
The system implements feedback by using the calculated measurement accuracy to modify future alarm decisions. The accuracy information feeds back into the alarm generation logic, creating a closed-loop system that continuously improves alarm reliability based on actual measurement quality
2Measurement precision
If alarm threshold is lowered to increase sensitivity, then detection capability is improved, but false alarm rate increases
Solution Approach 1:
The patent makes the alarm threshold dynamic rather than static. The threshold adapts in real-time based on the calculated accuracy of measurements, allowing the system to be more sensitive when accuracy is high and more conservative when accuracy is low, thereby reducing false alarms while maintaining detection capability
3Speed
If immediate alarm is generated when threshold is exceeded, then response time is improved, but alarm accuracy decreases
Solution Approach 1:
The system performs preliminary action by calculating measurement accuracy before generating an alarm. This preliminary accuracy assessment allows the system to determine whether an immediate alarm is appropriate or if further monitoring is needed, thereby improving alarm accuracy while maintaining appropriate response speed
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces nuisance alarms by ensuring that alarms are generated only when the SpO2 is likely to be outside the normal range with high accuracy, thereby improving the reliability and accuracy of pulse oximeter readings.
Implementation Method 1
Light, which may be produced by a light source integrated into the pulse oximeter, containing both red and infrared wavelengths is directed onto the skin of the patient and the light that passes through the skin is detected by the sensor. The intensity of light in each wavelength is measured by the sensor over time.
Implementation Method 2
The graph of light intensity versus time is referred to as the photoplethysmogram (PPG) or, more commonly, simply as the 'pleth.'
Implementation Method 3
calculating a probability distribution of an actual value of the physiological parameter based on data received from a sensor or detector
Implementation Method 4
The first accuracy is used to calculate a delay period after which, if the physiological parameter still exceeds the predetermined threshold, the alarm is generated.
Data Source
AI summary
Embodiments disclosed herein may describe systems and methods for reducing nuisance alarms using probability and/or accuracy of a measured physiological parameter, such as the pulse rate or SpO2 measurement generated by a pulse oximeter. Embodiments may include methods for adjusting a predetermined alarm threshold based on the probability distribution of the estimated pulse rate and/or oxygen saturation of a patient's blood.