Apparatus and method for monitoring nitric oxide delivery

1. A method of monitoring the delivery of therapeutic gas to a patient comprising:

receiving to a gas delivery device a desired concentration of therapeutic gas;

providing a flow of breathing gas;

providing a flow of therapeutic gas comprising nitric oxide;

delivering a combined flow of the breathing gas and the therapeutic gas to a patient;

measuring via a first flow sensor a measured flow rate of the breathing gas;

obtaining a flow rate of the therapeutic gas that is one of a measured flow rate and a known flow rate;

determining, using the flow rate of the therapeutic gas and the flow rate of the breathing gas, a calculated delivered concentration of therapeutic gas in the combined flow; and

presenting on a display a visual indication of the calculated delivery concentration of nitric oxide as a percentage comparison to the desired delivery concentration, wherein the visual indication includes a first region representing over delivery and a second region representing under delivery wherein the visual indicator further includes a marker associated with one of the first region and second region.

2. The method of claim 1 further comprising comparing the measured flow of breathing gas to a predetermined flow limit and providing an alert if the measured flow of breathing gas is above or below the flow limit.

3. The method of claim 2 , wherein the alert includes one or more of an audible alert, a visual alert and a text alert.

4. The method of claim 2 , wherein the predetermined flow limit comprises a low flow limit equal to or less than 0.25 L/min.

5. The method of claim 2 , wherein the predetermined flow limit comprises a high flow limit.

6. The method of claim 2 , further comprising adjusting the flow of breathing gas delivered to the patient in response to the alert.

7. The method of claim 1 , further comprising presenting the measured flow of breathing gas on the display, wherein displaying the measured flow of breathing gas includes displaying one or more of volumetric flow rate, tidal volume, and minute ventilation.

8. The method of claim 1 , further comprising presenting the measured flow of breathing gas on the display, wherein the measured flow of breathing gas is one or more of an average flow rate, an instantaneous flow rate, a peak flow rate and a minimum measured flow rate.

9. The method of claim 1 wherein the visual indication includes an over delivery region, an under delivery region and disposed between the over delivery region and under delivery region a target delivery region, and further includes an arrowhead indicating the delivered concentration of therapeutic gas.