Claims for Patent: 6,125,846

Summary for Patent: 6,125,846

Title:	Purge system for nitric oxide administration apparatus
Abstract:	A nitric oxide delivery system is disclosed that delivers a pulsed volume of NO containing therapeutic gas to a patient upon each inhalation of the patient. The NO delivery system includes certain functions to provide protection against the inadvertent inclusion of NO.sub.2 in the therapeutic gas administered to the patient. One of the functions is to provide a purge upon start up of the delivery system apparatus that clears the regulator and conduits of any NO.sub.2 that may have formed during the prior idle period of the system. A detector determines the start-up and may automatically carry out the purge cycle or may cause a prompt that is visual or audible to remind the user to carry out the purge cycle manually. As a further function, when the NO apparatus is terminated with respect to a patient, the system can, again, sense the termination or cessation of the therapy and automatically shut off the supply of NO containing gas at the source or provide an audible or visual prompt to remind the user to shut off the supply of the NO containing gas manually.
Inventor(s):	Bathe; Duncan P. L. (Madison, WI), Montgomery; Frederick J. (Sun Prairie, WI)
Assignee:	Datex-Ohmeda, Inc. (Madison, WI)
Application Number:	08/857,925
Patent Claims:	1. A method for purging a nitric oxide delivery system of an oxygen containing gas to avoid the production of nitrogen dioxide in the system, said method comprising the steps of: placing the system in an active state in which the system is capable of delivering nitric oxide containing gas to a patient; sensing the commencement of the active state to initiate a purging of a conduit through which the nitric oxide containing gas is delivered from a source to a patient, the purging being carried out by passing nitric oxide containing gas along the conduit for a predetermined period of time to remove oxygen containing gas from the delivery system; sensing a physical parameter of purging gas passage in the conduit to verify occurrence of the purge; and delivering nitric oxide containing gas to a patient when the purge has been completed. 2. A method of purging a nitric oxide delivery system as defined in claim 1 wherein said step of purging includes the step of opening a location on the conduit and passing the nitric oxide containing gas into and through the conduit to vent through the opening. 3. A method of purging a nitric oxide delivery system as defined in claim 1 wherein said step of sensing a parameter comprises sensing the pressure of gas in the conduit. 4. A method of purging a nitric oxide delivery system as defined in claim 1 wherein said step of sensing a parameter comprises sensing the flow of gas in the conduit. 5. A method for purging a nitric oxide delivery system of an oxygen containing gas to avoid the production of nitrogen dioxide in the system, said method comprising the steps of: placing the system in an inactive state in which delivery of nitric oxide containing gas to a patient is not carried out; sensing the inactive state of the system and thereafter sealing a source of nitric oxide containing gas to avoid production of nitrogen dioxide in the source from oxygen containing gases in the system; and purging a conduit by which the nitric oxide containing gas is delivered from the source to a patient, the purging being carried out by passing nitric oxide containing gas along the conduit for a predetermined period of time to remove oxygen containing gas from the delivery system. 6. A method of purging a nitric oxide delivery system as defined in claim 5 further including the step of sensing a physical parameter of the purging gas passage in the conduit to verify occurrence of the purging and sealing of the source of nitric oxide containing gas. 7. A method for purging a nitric oxide delivery system of an oxygen containing gas to avoid the production of nitrogen dioxide in the system, said method comprising the steps of: placing the system in an active state in which the system is capable of delivering nitric oxide containing gas to a patient; sensing the commencement of the active state to initiate a purging of a conduit through which the nitric oxide containing gas is delivered from a source to a patient, the purging being carried out by passing nitric oxide containing gas along the conduit for a predetermined period of time to remove oxygen containing gas from the delivery system; and delivering nitric oxide containing gas to a patient when the purge has been completed. 8. A method of purging a nitric oxide delivery system as defined in claim 7 wherein said step of purging includes the step of opening a location on the conduit and passing the nitric oxide containing gas into and through the conduit to vent through the opening. 9. A method for purging a nitric oxide delivery system of oxygen containing gas to avoid the production of nitrogen dioxide in the system, said method comprising the steps of: placing the system in an active state in which the system is capable of delivering nitric oxide containing gas to a user; sensing the commencement of the active state to provide a prompt to a user of the system calling for the initiating of a purging of the system; sensing a physical parameter of gas passing in the conduit as a result of a user initiated purge to verify occurrence of the purge; and delivering nitric oxide containing gas to a user when the purge has been completed. 10. A method of purging a nitric oxide delivery system as defined in claim 9 further defined as providing a further prompt to a user indicating that a purge has taken place. 11. A method of purging a nitric oxide delivery system as defined in claim 9 wherein said step of sensing a parameter comprises sensing the pressure of the nitric oxide containing gas in the conduit. 12. A method of purging a nitric oxide delivery system as defined in claim 9 wherein said step of sensing a parameter comprises sensing the flow of the nitric oxide containing gas in the conduit. 13. A method for purging a nitric oxide delivery system of an oxygen containing gas to avoid the production of nitrogen dioxide in the system, said method comprising the steps of: placing the system in an inactive state in which delivery of nitric oxide containing gas to a user is not carried out; sensing the inactive state of the system to provide a prompt to a user of the system calling for a user initiated sealing of a source of nitric oxide containing gas and a user initiated purging of a conduit by which the nitric oxide containing gas is delivered from the source to a user, the purging being carried out by passing nitric oxide containing gas along the conduit for a predetermined period of time to remove oxygen containing gas from the delivery system to avoid production of nitrogen dioxide in the source from oxygen containing gases in the system; and sensing a physical parameter of the purging gas passage in the conduit to verify occurrence of the purging and sealing of the source of nitric oxide containing gas. 14. A method for purging a nitric oxide delivery system of oxygen containing gases to avoid the production of nitrogen dioxide in the system, said method comprising the steps of: placing the system in an active state in which the system is capable of delivering nitric oxide containing gas to a user; sensing the commencement of the active state to provide a prompt to a user calling for the initiation of a purging of the system; and delivering nitric oxide containing gas to a user when the purge has been completed. 15. A method for purging a nitric oxide delivery system of an oxygen containing gas to avoid the production of nitrogen dioxide in the system, said method comprising the steps of: placing the system in an inactive state in which delivery of nitric oxide containing gas to a user is not carried out; and sensing the inactive state of the system to provide a prompt to a user calling for a user initiated sealing of a source of nitric oxide containing gas and a user initiated purging of a conduit by which the nitric oxide containing gas is delivered from the source to a patient, the purging being carried out by passing nitric oxide containing gas along the conduit for a predetermined period of time to remove oxygen containing gas from the delivery system to avoid production of nitrogen dioxide in the source from oxygen containing gases in the system; and delivering nitric oxide containing gas to a user when the purge has been completed.