The Science Journal of the American Association for Respiratory Care
Background: Inhaled Nitric Oxide (INO) has been shown to be a selective pulmonary vasodilator and has been used post-op on cardiac surgery patients. In our institutions INO is most frequently administered in conjunction with mechanical ventilation with the Datex-Ohmeda INOvent. In some instances it has been necessary to continue INO therapy after the patient has been weaned from mechanical ventilation. We tested the performance of the INOvent adapted to a nasal cannula. This would give us the flexibility to use the same NO delivery device for both spontaneously breathing and ventilator dependant patients. Description: The INOvent is a self-contained delivery and monitoring system. It incorporates a flow sensor/injector module. For spontaneously breathing patients INO is administered via a nasal cannula.
Methods: A flowmeter is incorporated to control a carrier gas (21-100% O2) at 2-8lpm through the flow sensor into a mixing tube and into a standard nasal cannula. Gas is sampled at the exit of the mixing tube for NO, NO2 and O2. For purposes of this study the gas was sampled at the end of a 7
Results: Flowmeter settings of 2-8 lpm (O2 or air) can deliver 20 and 40ppm NO continuously through a standard nasal cannula. Flowmeter settings of 7-8 lpm (O2 or air) can deliver 80ppm NO continuously through a standard nasal cannula. NO2 levels remained well below the EPA standard of 5ppm as well as below our institutional standard of 2ppm. Limiting factors that were identified during testing include: 1) 80ppm could not be maintained with flow meter settings below 7 lpm. 2) Flow meter settings below 2 lpm resulted in erratic NO readings. Conclusion: INO via nasal cannula can be easily and safely accomplished utilizing the INOvent.