MEASUREMENT OF EXPIRED NITRIC-OXIDE LEVELS IN CHILDREN

Nitric oxide (NO) can be measured directly in expired air in adults. T he purpose of our study was to measure NO levels in children and to co mpare these values with adults. Exhaled MO was measured in 39 normal p repubertal children (23 girls), aged 9-11 years(mean, 9.9 years). Exha led NO was measured by the chemiluminescence method that is sensitive in a range of 2 to 4,000 ppb of NO on an adapted analyzer (Dasibi Envi ronmental). Wearing a nose clip, 5 measurements were recorded in each child with exhalation I)directly into the NO analyzer (flow rate 240 m L/min) with measurements of NO, carbon dioxide, and mouth pressure; an d 2) using a T-piece to allow measurements at a different flow rate. F or all measurements, background NO levels were less than 10 ppb. The m ean direct lever was 49.6 ppb, SD 37.8 (range, 11.5-197.2 ppb) compare d with T-piece levels of 29.2 ppb, SD 27.1 (range, 5.1-141.2 ppb). The re was no significant difference between boys and girls for direct or T-piece recordings. Mean direct NO in boys was 43.1 ppb, SD 40.5 and i n girls 55.2 ppb, SD 35.4; mean T-piece in boys was 25.6 ppb, SD 29.2, and in girls 33.8 ppb, SD 25.1. Mean NO levels in prepubertal childre n are fewer than in adults and show no difference between males and fe males. (C) 1996 Wiley-Liss, Inc.