Systems and method for delivery of therapeutic gas to patients in need thereof using enhanced breathing circuit gas (BCG) flow measurement
Inventors
Acker, Jaron M. • Tolmie, Craig R.
Assignees
Mallinckrodt Pharma IP Trading DAC • Therakos Inc • INO Therapeutics LLC • Mallinckrodt Critical Care Finance Inc
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Publication Number
US-10226592-B2
Publication Date
2019-03-12
Expiration Date
Abstract
The present invention generally relates to systems and method for delivery of therapeutic gas to patients in need thereof using enhanced breathing circuit gas (BCG) flow measurement. At least some of these enhanced BCG flow measurements can be used to address some surprising phenomena that may, at times, occur when wild stream blending therapeutic gas into breathing gas that a patient receives from a breathing circuit affiliated with a ventilator. Utilizing at least some of these enhanced BCG flow measurements the dose of therapeutic gas wild stream blended into breathing gas that the patient receives from a ventilator can at least be more accurate and/or over delivery of therapeutic gas into the breathing gas can be avoided and/or reduced.
Core Innovation
The invention relates to administering therapeutic gas, comprising nitric oxide, to a patient through a breathing circuit affiliated with a ventilator by detecting a flow direction of a breathing gas relative to the ventilator. Flow is identified as forward direction when flowing from the ventilator towards the patient and as reverse direction when flowing from the patient towards the ventilator, and a control valve is opened for forward direction flow to deliver the therapeutic gas into the breathing gas and closed for reverse direction flow to cease delivery.
A reverse BCG flow phenomenon is addressed by determining a volume of reverse flow and determining a volume of resumed forward flow. Delivery is compensated for the flow in the reverse direction by opening the control valve to resume delivery only after the volume of forward flow is at least equal to the volume of reverse flow, preventing therapeutic gas dose from being over or under delivered.
In certain implementations, the invention further compensates based on dead space volume and a lesser-of volume timing constraint to control when delivery resumes in forward direction after reverse direction flow. For single-limb breathing circuit and BiPAP ventilator scenarios, the forward-flow resumption rule can be varied based on the ventilator type and breathing-circuit configuration, and carbon dioxide may be measured in at least a portion of the reverse flow so that therapeutic gas is delivered only into reverse-flow portions containing carbon dioxide and not delivered into reverse-flow portions not containing carbon dioxide.
Claims Coverage
The independent claims are directed to a method of administering therapeutic gas by detecting forward versus reverse flow and compensating delivery using forward/reverse flow volumes, and to a nitric oxide delivery system that implements that method using an injector module with a control valve and a bi-directional BCG flow sensor.
Flow direction-based control valve actuation for therapeutic gas delivery
Measuring a flow direction of a breathing gas through and/or in fluid communication with a breathing circuit affiliated with a ventilator; determining forward direction and opening a control valve to deliver therapeutic gas into the breathing gas; determining reverse direction and closing the control valve and ceasing delivery of the therapeutic gas into the breathing gas.
Volume compensation to resume delivery after reverse flow
Determining a volume of reverse flow; determining a volume of resumed forward flow; compensating for flow in the reverse direction by opening the control valve to resume delivery of the therapeutic gas into the breathing gas after the volume of forward flow is at least equal to the volume of reverse flow.
Injector module with bi-directional BCG flow sensor and control module for forward/reverse determination
An injector module for delivering a therapeutic gas into a breathing gas in a breathing circuit, wherein the injector module comprises an injector body with openings configured to couple to the breathing circuit, a therapeutic gas inlet to receive and inject the therapeutic gas, and at least one bi-directional BCG flow sensor capable of measuring breathing gas flow in a forward direction and in a reverse direction, and a control valve in communication with the therapeutic gas inlet, and a control module in communication with the at least one bi-directional BCG flow sensor and the control valve to determine a volume of forward flow and a volume of reverse flow.
Therapeutic gas delivery inhibit during reverse flow and volume-compensated resumption
When the at least one bi-directional BCG flow sensor measures flow in the reverse direction, the control valve is closed and the therapeutic gas is not delivered into the breathing circuit via the therapeutic gas inlet; when the at least one bi-directional BCG flow sensor measures flow in the forward direction after reverse direction, the therapeutic gas is delivered into the breathing circuit after compensating for the flow in the reverse direction by opening the control valve after the volume of resumed forward flow is at least equal to the volume of reverse flow.
Across the independent claims, the core claim coverage is the combination of forward/reverse flow direction measurement, closing the control valve and ceasing delivery during reverse flow, and resuming delivery only after volume compensation so that resumed forward-flow volume is at least equal to reverse-flow volume; the system claim further recites implementing this with an injector module, therapeutic gas inlet, control valve, control module, and at least one bi-directional BCG flow sensor, where the therapeutic gas comprises nitric oxide.
Stated Advantages
Prevents therapeutic gas dose from being over or under delivered by compensating for reverse-direction flow.
Documented Applications
Administering nitric oxide therapy to a patient using a ventilator-associated breathing circuit, including scenarios involving reverse flow and forward-flow volume compensation.
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