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 • Therakos Inc • INO Therapeutics LLC • Mallinckrodt Critical Care Finance Inc
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Publication Number
US-10046125-B2
Publication Date
2018-08-14
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. 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 relates to methods of compensating for nitric oxide sensor drift in a nitric oxide delivery device. It stores a calibration schedule in memory associated with the nitric oxide delivery device and, in response to a set dosage change, selects calibration intervals according to the magnitude of the set dosage change.
The method performs zero calibrations by exposing the nitric oxide sensor to a gas having a zero concentration of nitric oxide and adjusting a calibration line according to detected current output or measured output. In some embodiments, the zero calibrations are performed after first and second intervals selected according to the magnitude of the set dosage change, and successive zero calibrations occur at successive increasing time intervals according to the calibration schedule, with a maximum interval value controlling further interval behavior.
The invention further includes storing calibration schedule(s) and a calibration line in memory associated with the nitric oxide delivery device and selecting one of the calibration schedules according to the magnitude of the set dosage change. In these embodiments, the nitric oxide delivery device is configured to deliver nitric oxide to a breathing circuit, and the zero calibrations include exposing the nitric oxide sensor to ambient air having a zero concentration of nitric oxide while adjusting the calibration line based on measured output.
Claims Coverage
The provided excerpt includes three independent claims, each centered on compensating nitric oxide sensor drift through stored calibration schedule(s), interval-based zero calibrations selected according to set dosage change magnitude, and calibration line adjustment based on sensor output.
Calibration schedule selecting first and second zero calibration intervals based on set dosage change magnitude
Storing, in memory associated with a nitric oxide delivery device, a calibration schedule; selecting, in response to a set dosage change, according to the calibration schedule, a first zero calibration after a first interval and a second zero calibration after a second interval; selecting the first interval and the second interval according to a magnitude of the set dosage change; and performing the first and second zero calibrations by exposing the nitric oxide sensor to a gas having a zero concentration of nitric oxide and adjusting a calibration line according to a detected current output of the nitric oxide sensor during the second zero calibration.
System controller receiving set dosage change and performing interval-based zero calibrations while delivering to a breathing circuit
Storing in memory associated with a nitric oxide delivery device a calibration schedule and a calibration line; receiving a set dosage change of nitric oxide to the system controller; delivering the set dosage of nitric oxide to a breathing circuit from the nitric oxide delivery device; determining according to the calibration schedule a first zero calibration at a first interval and a second zero calibration at a second interval, with the first interval and second interval selected according to a magnitude of the set dosage change; performing the first zero calibration after the first interval and performing the second zero calibration after the second interval; and exposing the nitric oxide sensor to a gas having a zero concentration of nitric oxide and adjusting the calibration line.
Selecting one calibration schedule and performing zero calibrations using ambient air with zero concentration
Storing in a memory associated with a nitric oxide delivery device at least one calibration schedule and a calibration line; receiving a set dosage change to the system controller; selecting one of the at least one calibration schedules according to a magnitude of the set dosage change; performing a first zero calibration after a first interval and a second zero calibration after a second interval; where each zero calibration includes exposing the nitric oxide sensor to ambient air having a zero concentration of nitric oxide and adjusting the calibration line according to a measured output of the nitric oxide sensor.
Across the independent claims, the inventive core is interval-based zero calibration scheduling tied to the magnitude of a set dosage change, using stored calibration schedule(s) to select first and second zero calibration intervals, delivering nitric oxide to a breathing circuit in at least one embodiment, and adjusting a calibration line based on sensor output while exposing the nitric oxide sensor to zero-concentration gas or ambient air with zero concentration.
Stated Advantages
Compensates for nitric oxide sensor drift.
Documented Applications
Delivering nitric oxide to a breathing circuit with a nitric oxide delivery device and compensating for nitric oxide sensor drift.
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