Systems and methods for compensating long term sensitivity drift of electrochemical gas sensors exposed to nitric oxide
Inventors
Tolmie, Craig R. • Milsap, Jeff • Acker, Jaron M.
Assignees
Mallinckrodt Pharma IP Trading DAC • Mallinckrodt Pharmaceuticals Ireland Ltd • Therakos Inc • INO Therapeutics LLC • Mallinckrodt Critical Care Finance Inc
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Publication Number
US-9919118-B2
Publication Date
2018-03-20
Expiration Date
Abstract
Systems and methods for compensating long term sensitivity drift of catalytic type electrochemical gas sensors used in systems for delivering therapeutic nitric oxide (NO) gas to a patient by compensating for drift that may be specific to the sensors. In at least some instances, the long term sensitivity drift of catalytic type electrochemical gas sensors can be addressed using calibration schedules, which can factor in the absolute change in set dose of NO being delivered to the patient that can drive one or more baseline calibrations. The calibration schedules can reduce the amount of times the sensor goes offline. Systems and methods may factor in actions occurring at the delivery system and/or aspects of the surrounding environment, prior to performing a baseline calibration, and may postpone the calibration and/or rejected using the sensor's output for the calibration.
Core Innovation
The invention addresses sensor output drift during therapeutic gas delivery by performing a calibration according to a calibration schedule for a sensor associated with a therapeutic gas delivery device. The calibration includes exposing the sensor to a zero concentration of the therapeutic gas and adjusting a baseline calibration value according to a sensor output value during the calibration.
During therapeutic gas delivery, the method monitors a patient intake of therapeutic gas with a sensor and delivers a predetermined dosage of therapeutic gas to the patient. The method measures a concentration of therapeutic gas from the delivered predetermined dosage and, upon completion of the calibration, determines an actual concentration of therapeutic gas delivered by adjusting the value of the measured concentration based on the adjusted baseline value and the slope.
The invention further provides user notifications of calibration status during the calibration, including that the measuring of therapeutic gas concentration is off-line. The notifying is implemented as a notification during the performance of the calibration that the calibration is currently in effect, and in some implementations the notification includes disabling an alarm associated with the sensor.
Claims Coverage
The patent includes two independent claims, each covering a method for delivering notifications of a calibration status for a sensor associated with a therapeutic gas delivery device and compensating measured therapeutic gas concentration for sensor drift using calibration-adjusted baseline parameters.
Calibration status notification with baseline/slope calibration parameters
Storing in memory a baseline calibration value, slope, and calibration schedule; performing a calibration according to the calibration schedule that includes exposing the sensor to a zero concentration of the therapeutic gas and adjusting the baseline calibration value according to a sensor output value during the calibration; notifying a user, during the performance of the calibration, that the calibration is currently in effect and that the measuring of therapeutic gas concentration is off-line; and, upon completion, determining an actual concentration of therapeutic gas delivered to compensate for sensor drift by adjusting the value of the measured concentration based on the adjusted baseline value and the slope.
Display-based calibration in-effect notification with alarm disable
Storing in memory a baseline calibration value, slope, and calibration schedule; performing a calibration according to the calibration schedule that includes exposing the sensor to a zero concentration of the therapeutic gas and adjusting the baseline calibration value according to a sensor output value during the calibration; notifying a user, during the performance of the calibration, that the calibration is currently in effect where the notifying includes displaying a notification on the display screen that the measuring of therapeutic gas concentration is off-line and that an alarm associated with the sensor has been disabled; and, upon completion of the calibration, determining an actual concentration of therapeutic gas delivered to compensate for sensor drift by adjusting the value of the measured concentration based on the adjusted baseline value and the slope.
Across the independent claims, the coverage centers on scheduled calibration using a zero concentration exposure and baseline adjustment, user notification that measurement is off-line during calibration, and compensating the delivered therapeutic gas concentration after calibration using the adjusted baseline value and the slope. The second independent claim further specifies a display-based notification that measurement is off-line while an alarm associated with the sensor has been disabled.
Stated Advantages
Compensating for sensor drift by adjusting the measured therapeutic gas concentration based on calibration-adjusted baseline value and slope.
Providing user notification during calibration that the calibration is currently in effect and that measurement of therapeutic gas concentration is off-line.
Disabling an alarm associated with the sensor during calibration while communicating calibration status to the user.
Documented Applications
Therapeutic gas delivery using a sensor associated with a therapeutic gas delivery device, with calibration status notifications for a calibration process to address sensor drift.
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