Objectives: Clinical applications of inhaled nitric oxide (NO) therapy resulted in the development of delivery systems and monitoring devices applicable to routine clinical care. This article presents the various components necessary for an adequate clinical use of inhaled NO, and discusses the NO gas mixture cylinders, inhaled NO delivery techniques and specifications, monitoring devices, and ending with an exhaustive description of the scavengers of nitrogen oxides (NOx).
Data sources: Computerized search (CURRENT CONTENTS, MEDLINE) of published original research and review articles (approximately 200), conference abstracts and compendiums up to May 1997 (approximately 50), personal files, and contact with expert informants.
Study selection: Technical, experimental, and clinical reports were selected from the recent English, French, German, and Spanish literature, if pertinent to the administration or monitoring of inhaled NO.
Data extraction: The authors extracted all applicable data.
Data synthesis: The production of NO gas mixture cylinders must be certified with respect to gas purity, stability, and concentration (limits between 100 and 1000 ppm), guaranteed calibration, and specific color. An ideal inhaled NO delivery device requires a synchronized delivery, a minimal production of nitrogen dioxide (NO2), and should be simple to use (verification, calibration, convenient flushing, cylinder change possible while in use and a simple alarm setting) with full information (high and low alarms and available precision monitoring of NO, NO2, and O2). Emergency and transport systems must be readily available. The choice of the monitoring device (chemiluminescence or electrochemistry) should be made based on the knowledge of their strength and weakness for a particular clinical application. Finally, scavengers of NOx should be used with caution until specific filters are proven safe and effective.
Conclusions: The great expectancies generated by inhaled NO action have led researchers to design personal inhaled NO delivery systems, but only with mitigated results. At present, medical companies are finding a financial interest in designing a delivery system which will suit the needs of clinicians and this, along with official governmental approval, will only then permit the use of inhaled NO safely and on a larger scale.