System and elements for managing therapeutic gas administration to a spontaneously breathing non-ventilated patient
View Patent ↗A system controls and manages administration of a therapeutic gas, such as NO, O 2 , or the like, to a spontaneously breathing, non-ventilated patient such that concentrated NO is as low as reasonably possible while delivering the desired amount of NO to the distal portions of the lungs. The system includes an entrainment cell that provides remote, turbulent mixing with low temporal latency and can be used with a nasal cannula or a mask. The entrainment cell uses room air to dilute the therapeutic gas; however, supplementary gases can also be used. A baffle can be included to promote mixing and a flow sensor can also be used if desired. Multiple ports can be included in the entrainment cell. An equalizing valve is also disclosed.
1. A low dead volume pressure equalizing device for high purity gas circuits comprising: means for providing a flow versus pressure dead band, and means for providing zero flow in either direction at non-zero differential pressures.
2. The device defined in claim 1 further including an inlet fitting to a gas circuit and means for connecting the device to said inlet fitting and further including a pin for minimizing dead space.
3. The device defined in claim 2 further including a plunger, first and second sealing surfaces, opposed springs acting on said plunger, and an intermediate region of plunger travel during which flow will be prohibited.
4. The device defined in claim 3 wherein said dead band is symmetric in differential pressure about zero with respect to non-zero flow in either direction.
5. The device defined in claim 3 wherein characteristics of said springs determine whether said dead band is symmetric or asymmetric in differential pressure about zero with respect to non-zero flow in each direction.
6. The device defined in claim 5 further including safety means for preventing flow rates beyond a preset value in an event of otherwise unconstrained flow.
7. The device defined in claim 6 wherein said safety means includes means for changing flow restriction based on flow rates.
8. The device defined in claim 1 wherein the pressure equalizing device is located inside an inlet fitting to a gas circuit.