Abstract

BACKGROUND
Fraction of exhaled nitric oxide (FENO) is known as a marker of inflammation in asthma, cystic fibrosis and exacerbation of COPD. However, its importance has not been established in patients using mechanical ventilation. We assessed whether FENO is elevated in patients with ventilator associated pneumonia (VAP), and physiologic or pathologic factors affecting levels of FENO in patients with mechanical ventilation.
METHODS
All patients (over 18-year-old) using mechanical ventilation were included, and among them, VAP patients were diagnosed on the basis of clinical pulmonary infection score (CPIS). We measured FENO in air collected during the end-expiratory pause via an off-line method. We compared the levels of FENO between patients with VAP and without, and assessed the relationship between FENO and other physiologic or pathologic characteristics; age, gender, PaO2, oxygenation index, CPIS.
RESULTS
A total of 43 patients (23 male, mean age 67.7 +/- 10.7) in an ICU were enrolled; 19 of them were VAP-patients (10 male, mean age 64.8 +/- 12.9). The level of FENO in the VAP-patients was substantially higher than in the non-VAP group (55.8 +/- 25.3 ppb Vs. 31.8 +/- 13.5 ppb, p < 0.001). CPIS on day 1 and day 3, and duration of mechanical ventilation, were associated with the level of FENO, but oxygenation index, PaO2, PaO2/FiO2, and the mean PEEP were not.
CONCLUSIONS
FENO may be useful for the diagnosis of VAP, and is related to CPIS, as well as the duration of mechanical ventilation.

• Keywords: clinical pulmonary infection score (CPIS);diagnosis;fraction of exhaled nitric oxide (FENO);ventilator associated pneumonia (VAP);