Accurate dose nitric oxide pulse delivery device with monitoring and alarms

• US 6,164,276 A
• Filed: 05/26/1998
• Issued: 12/26/2000
• Est. Priority Date: 05/16/1997
• Status: Expired due to Term

• Current Assignee: Mallinckrodt Critical Care Finance Inc (Mallinckrodt plc), Mallinckrodt Pharma Ip Trading DAC (Mallinckrodt plc), Therakos, Inc (Mallinckrodt plc)
• Original Assignee: Datex-Ohmeda Incorporated (General Electric Company)
• Inventors: Montgomery, Frederick J., Bathe, Duncan P. L.
• Primary Examiner(s): Weiss, John G.
• Assistant Examiner(s): WEISS JR, JOSEPH
• Application Number:
  US09/084,710
• Time in Patent Office: 945 Days
• Field of Search: 128/202.22, 128/203.12, 128/203.14, 128/204.18, 128/204.23, 128/205.23, 128/205.24, 128/205.25, 128/204.21
• US Class Current: 128/202.22
• CPC Class Codes: A61F 2/06 Blood vessels
• CPC Class Codes: A61F 2/24 Heart valves ; Vascular valves, e.g. venous valves; Heart implants, e.g. passive devices for improving the function of the native valve or the heart muscle; Transmyocardial revascularisation [TMR] devices; Valves implantable in the body
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/0677 Gas-saving devices therefor
• CPC Class Codes: A61M 16/10 Preparation of respiratory gases or vapours
• CPC Class Codes: A61M 16/12 by mixing different gases
• CPC Class Codes: A61M 16/202 electrically actuated
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2202/0275 Nitric oxide [NO]

Abstract

A respiratory therapy apparatus that delivers a predetermined precise volume of a therapeutic gas to a patient upon each inhalation of the patient. The apparatus has a flow sensing device and a valve that opens and closes to deliver the pulse to the patient. A CPU controls the open time of the valve and also uses the flow to the patient determined by the flow sensing device and the time the valve is in the open position to determine the volume of therapeutic gas to the patient. A user input device communicates a user desired volume to be delivered to the patient and the CPU compares the user input desired volume with the calculated volume and adjusts the time the valve is in the open position to cause the apparatus to deliver to the patient the precise desired volume inputted by the user. In one embodiment the system senses and used the ambient temperature and ambient pressure to determine the correct volume of gas delivered to the patient. The apparatus thus provides a precise volume of therapeutic gas to the patient during each inhalation independent of supply pressure of the therapeutic gas, the ambient pressure, ambient temperature or the size of the inhalation.

Claims

1. A respiratory therapy apparatus delivering a pulsed dose of nitric oxide gas to a patient, said apparatus having an alarm system and comprising:

conduit means connecting said respiratory therapy apparatus to a source of nitric oxide gas under pressure,

means to establish a predetermined desired dose of nitric oxide gas to be delivered along the conduit means to the patient during each inhalation,

sensing means for sensing the initiation of an inhalation of the patient,

delivery control means coupled to said conduit means and responsive to said sensing means sensing an inhalation of the patient to deliver a pulsed dose of nitric oxide gas along the conduit means to the patient during each inhalation of the patient,

a control means for controlling the delivery control means to deliver the dose of nitric oxide gas,

a measurement means to detect a fault by measuring the volume of the delivered pulsed dose, comparing the measured volume against the desired volume of the dose, and detecting a fault when the measured volume is greater or less than the desired dose volume be a given amount;

an alarm to alert the user of a fault condition, and means to activate said alarm when said measurement means has detected a fault.

2. A respiratory therapy apparatus as defined in claim 1, wherein said measurement means detects a fault when the measured volume differs from the desired dose volume by at least about 30 percent.

3. A respiratory therapy apparatus as defined in claim 1 wherein said conduit means has an orifice through which said dose is delivered to the patient and wherein said measurement means determines the mass flow of said pulsed dose through said orifice.

4. A respiratory therapy apparatus as defined in claim 3 wherein said respiratory therapy apparatus further includes a sensor for determining ambient temperature and a sensor for determining ambient pressure and said measurement means converts said determined mass flow of said pulsed dose to volumetric flow using said determined ambient temperature and pressure.

5. A respiratory therapy apparatus as defined in claim 1 wherein said apparatus further includes a sensor for determining ambient temperature and a sensor for determining ambient pressure and said measurement means corrects said control means in accordance with said ambient temperature and said ambient pressure determinations.

6. A respiratory therapy apparatus delivering a dose of nitric oxide gas to a patient, said apparatus having an alarm system and comprising:

a conduit adapted to be connected to a source of nitric oxide gas under pressure and to a patient,

said conduit including a valve controlling the flow of the nitric oxide gas from the source to the patient,

control means to open and close said valve at timed intervals by sending a signal to open said valve and a signal to close said valve to deliver accurate doses of the nitric oxide gas along the conduit to the patient,

a sensor adapted to detect a condition of the dose of nitric oxide gas in said conduit,

an alarm activatable to alert the user of a fault condition, and

means to activate said alarm when a signal has been sent by said control means to close said valve and said sensor does not detect a corresponding change in the detected condition of the dose in said conduit indicative of the valve being moved to its closed position.

7. A respiratory therapy apparatus as defined in claim 6 wherein said sensor is a pressure sensor.

8. A respiratory therapy apparatus as defined in claim 6 wherein said sensor is a flow sensor.

9. A respiratory therapy apparatus delivering a dose of nitric oxide gas to a patient, said apparatus having an alarm system and comprising:

a conduit adapted to be connected to a source of nitric oxide gas under pressure and to a patient,

said conduit including a valve controlling the flow of the nitric oxide gas from the source to the patient,

control means to open and close said valve at timed intervals by sending a signal to open said valve and a signal to close said valve to deliver accurate doses of the nitric oxide gas along the conduit to the patient,

a sensor adapted to detect a physical condition in said conduit,

an alarm activatable to alert the user of a fault condition, and

means to activate said alarm when a signal has been sent by said control means to open said valve and said sensor does not detect a corresponding change in a physical condition in said conduit indicative of the valve being moved to its open position.

10. A respiratory therapy apparatus as defined in claim 9 wherein said sensor is a pressure sensor.

11. A respiratory therapy apparatus as defined in claim 9 wherein said sensor is a flow sensor.