INHALED NITRIC-OXIDE - TECHNICAL ASPECTS OF ADMINISTRATION AND MONITORING

Objectives: Clinical applications of inhaled nitric oxide (NO) therapy resulted in the development, of delivery systems and monitoring devic es applicable to routine clinical care. This article presents the vari ous components necessary for an adequate clinical use of inhaled NO, a nd discusses the NO gas mixture cylinders, inhaled NO delivery techniq ues and specifications, monitoring devices, and ending with an exhaust ive description of the scavengers of nitrogen oxides (NOx). Data Sourc es: Computerized search (CURRENT CONTENTS, MEDLINE) of published origi nal research and review articles (similar to 200), conference abstract s acid compendiums up to May 1997 (similar to 50), personal files, and contact with expert informants. Study Selection: Technical, experimen tal, and clinical reports were selected from the recent English, Frenc h, German, and Spanish literature, if pertinent to the administration or monitoring of inhaled NO. Data Extraction: The authors extracted al l applicable data. Data Synthesis: The production of NO gas mixture cy linders must be certified with respect to gas purity, stability, and c oncentration (limits between 100 and 1000 ppm), guaranteed calibration , acid 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 fl ushing, cylinder change possible while in use and a simple alarm setti ng) with full information (high and low alarms and available precision monitoring of NO, NO2, and O-2). Emergency and transport systems must toe readily available. The choice of the monitoring device (chemilumi nescence or electrochemistry) should he made based on the knowledge of their strength and weakness for a particular clinical application. Fi nally, scavengers of NOx should be used with caution until specific fi lters are proven safe and effective. Conclusions: The great expectanci es generated by inhaled NO action have led researchers to design perso nal inhaled NO delivery systems, but only with mitigated results. At p resent, medical companies are finding a financial interest in designin g a delivery system which will suit the needs of clinicians and this, along with official governmental approval, will only then permit the u se of inhaled NO safely and on a larger scale.