Systems and method for delivery of therapeutic gas to patients, in need thereof, receiving breathing gas from a ventilator that varies at least pressure and/or flow using enhanced therapeutic gas (no) flow measurement

Abstract

The present disclosure generally relates to systems and methods for delivery of therapeutic gas to patients, in need thereof, receiving breathing gas from a high frequency ventilator using at least enhanced therapeutic gas (e.g., nitric oxide, NO, etc.) flow measurement. At least some of these enhanced therapeutic gas flow measurements can be used to address some surprising phenomenon that may, at times, occur when wild stream blending therapeutic gas into breathing gas a patient receives from a breathing circuit affiliated with a high frequency ventilator. Utilizing at least some of these enhanced therapeutic gas flow measurements the dose of therapeutic gas wild stream blended into breathing gas that the patient receives can at least be more accurate and/or under delivery of therapeutic gas into the breathing gas can be avoided and/or reduced.

What is claimed is: 
     
         1 . A method of delivering nitric oxide gas to a patient in need thereof, the method comprising:
 providing, through at least one control valve of a nitric oxide delivery system, a flow of nitric oxide gas to an injector module configured to inject the nitric oxide gas into a breathing gas in an inspiratory limb of a breathing circuit affiliated with a high frequency ventilator or ventilation techniques which provide reverse and/or oscillations in inspiratory pressure or flow;   measuring, using at least one NO flow sensor, NO flow, wherein the at least one NO flow sensor is in fluid communication with a therapeutic gas inlet of the injector module;   receiving, using a control system in communication with the at least one NO flow sensor, flow information from the at least one NO flow sensor; and   delivering the nitric oxide gas to the patient.   
     
     
         2 . The method of  claim 1 , wherein the injector module has an injector body having a first opening and a second opening, the first opening and the second opening being configured to couple the injector module to the inspiratory limb of the breathing circuit enabling the breathing gas in the breathing circuit to flow through the first opening and the second opening. 
     
     
         3 . The method of  claim 2 , wherein the therapeutic gas inlet is in the injector body, the therapeutic gas inlet being configured to receive the flow of the nitric oxide gas and enable injection of the nitric oxide gas into the injector module, and in turn into the breathing gas in the inspiratory limb of the breathing circuit. 
     
     
         4 . The method of  claim 1 , wherein the control system is operable to:
 (i) detect use of the high frequency ventilator;   (ii) identify the flow information as missing and interpolate the missing flow information; and/or (iii) identify the flow information as reverse flow.   
     
     
         5 . The method of  claim 1 , wherein the therapeutic gas inlet receives the flow of nitric oxide gas from a nitric oxide source, via a conduit. 
     
     
         6 . The method of  claim 5 , wherein the nitric oxide source is a cylinder storing NO or an NO generator. 
     
     
         7 . The method of  claim 6 , further comprising generating the nitric oxide gas by reaction of a NO-releasing agent with a reductant using the NO generator. 
     
     
         8 . The method of  claim 7 , wherein the NO-releasing agent is nitrogen dioxide and the reductant is ascorbic acid. 
     
     
         9 . The method of  claim 1 , further comprising monitoring the flow information, using the control system, to ensure that a desired dose of NO is delivered into the injector module, and in turn into the breathing gas in the inspiratory limb of the breathing circuit. 
     
     
         10 . The method of  claim 1 , furthering comprising monitoring the flow information, using the control system, to ensure a desired does of NO is not under delivered and/or under dosed. 
     
     
         11 . The method of  claim 1 , further comprising opening or closing a check valve that is one or more of (i) in fluid communication with the therapeutic gas inlet of the injector module and (ii) is integral to the injector module. 
     
     
         12 . The method of  claim 1 , wherein the at least one NO flow sensor is at least one bi-directional flow sensor. 
     
     
         13 . The method of  claim 12 , wherein the at least one bi-directional flow sensor is a thermal mass flow meter or a thermal dispersion flow meter. 
     
     
         14 . The method of  claim 1 , wherein the inspiratory limb is also an expiratory limb in the breathing circuit. 
     
     
         15 . The method of  claim 1 , wherein the NO flow sensor is downstream of the control valve in the nitric oxide delivery system. 
     
     
         16 . The method of  claim 1 , wherein the control valve is upstream of the NO flow sensor in the nitric oxide delivery system. 
     
     
         17 . The method of  claim 1 , further comprising receiving the flow of nitric oxide gas at the therapeutic gas inlet via a conduit, wherein the conduit has one or more of (i) an internal cross-sectional diameter of about 1/32 of an inch to about ¼ of an inch and (ii) an internal portion within the nitric oxide delivery system and an external portion outside the nitric oxide delivery system, the internal portion of the conduit having a cross-sectional diameter that is substantially the same as a cross-sectional diameter of the external portion of the conduit. 
     
     
         18 . The method of  claim 1 , further comprising:
 measuring, using at least a second NO flow sensor, NO flow, wherein the second NO flow sensor is in fluid communication with the therapeutic gas inlet and in communication with the control system,   receiving, at the control system, flow information from the second NO flow sensor; and   detecting, using the control system, a leak when the flow information from the NO flow sensors does not match.   
     
     
         19 . The method of  claim 18 , further comprising increasing the flow of nitric oxide gas if a leak is detected. 
     
     
         20 . A method of delivering nitric oxide gas to a patient in need thereof, the method comprising:
 providing, through a conduit and at least one control valve of a nitric oxide delivery system, a flow of nitric oxide gas to a therapeutic gas inlet of an injector module from a nitric oxide gas source, wherein the nitric oxide is injected into a breathing gas in an inspiratory limb of a breathing circuit affiliated with a high frequency ventilator or ventilation techniques which provide reverse and/or oscillations in inspiratory pressure or flow;   measuring, using at least one bi-directional NO flow sensor, NO flow in a forward direction and in a reverse direction through the therapeutic gas inlet, wherein the at least one bi-directional NO flow sensor is in fluid communication with the therapeutic gas inlet;   receiving, using a control system in communication with the at least one bi-directional NO flow sensor, bi-directional flow information; and   delivering the nitric oxide gas to the patient.   
     
     
         21 . The method of  claim 20 , wherein the injector module has an injector body having a first opening and a second opening, the first opening and the second opening being configured to couple the injector module to the inspiratory limb of the breathing circuit enabling the breathing gas in the breathing circuit to flow through the first opening and the second opening. 
     
     
         22 . The method of  claim 21 , wherein the therapeutic gas inlet is in the injector body, the therapeutic gas inlet being configured receive the flow of the nitric oxide gas and enable injection of the nitric oxide gas into the injector module, and in turn into the breathing gas in the inspiratory limb of the breathing circuit. 
     
     
         23 . The method of  claim 20 , wherein the bi-directional flow information comprises at least forward flow information and reverse flow information. 
     
     
         24 . The method of  claim 20 , wherein the nitric oxide source is a cylinder storing NO or an NO generator. 
     
     
         25 . The method of  claim 24 , further comprising generating the nitric oxide gas by reaction of a NO-releasing agent with a reductant using the NO generator. 
     
     
         26 . The method of  claim 25 , wherein the NO-releasing agent is nitrogen dioxide and the reductant is ascorbic acid. 
     
     
         27 . The method of  claim 20 , further comprising monitoring the flow information, using the control system, to ensure that a desired dose of NO is delivered into the injector module, and in turn into patient breathing gas in the inspiratory limb of the breathing circuit. 
     
     
         28 . The method of  claim 20 , further comprising monitoring the flow information, using the control system, to ensure that a desired dose of NO is not under delivered and/or under dosed. 
     
     
         29 . The method of  claim 20 , further comprising opening or closing a check valve that is one or more of (i) in fluid communication with the therapeutic gas inlet of the injector module and (ii) is integral to the injector module. 
     
     
         30 . The method of  claim 20 , wherein the at least one bi-directional flow sensor is a thermal mass flow meter or a thermal dispersion flow meter. 
     
     
         31 . The method of  claim 20 , wherein the inspiratory limb is also an expiratory limb in the breathing circuit. 
     
     
         32 . The method of  claim 20 , wherein the NO flow sensor is downstream of the control valve in the nitric oxide delivery system. 
     
     
         33 . The method of  claim 20 , wherein the control valve is upstream of the NO flow sensor in the nitric oxide delivery system. 
     
     
         34 . The method of  claim 20 , wherein the conduit has one or more of (i) an internal cross-sectional diameter of about 1/32 of an inch to about ¼ of an inch and (ii) an internal portion within the nitric oxide delivery system and an external portion outside the nitric oxide delivery system, the internal portion of the conduit having a cross-sectional diameter that is substantially the same as a cross-sectional diameter of the external portion of the conduit. 
     
     
         35 . The method of  claim 20 , further comprising:
 measuring, using at least a second bi-directional NO flow sensor, NO flow, wherein the second bi-directional flow sensor is in fluid communication with the therapeutic gas inlet and in communication with the control system,   receiving, at the control system, flow information from the second bi-directional NO flow sensor; and   detecting, using the control system, a leak when the flow information from the NO flow sensors does not match.   
     
     
         36 . The method of  claim 35 , further comprising increasing the flow of nitric oxide gas if a leak is detected.