[Accuracy of measuring nitric oxide by the chemiluminescence: effect of measuring chamber pressure].

There are two ways of measuring nitric oxide (NO) by chemiluminescence; one reduces pressure in the NO reaction chamber, and the other does not. Devices with a reduced pressure chamber tend to be more accurate, but can be bulky and cumbersome to use. Devices without reduced pressure chamber can be useful because of their smaller size and short warm-up time. We compared the accuracy of two methods by measuring delivered gas concentrations after changing ventilatory parameters. The values of nitric dioxide (NO2) measured varied more widely than those of NO. NO2 measurements were particularly variable with changes in humidity. We consider the accuracy of NO measured by the chemiluminescence devices to be accurate for clinical monitor, but the accuracy of NO2 measurement must be improved to make NO therapy safer.