Diagnostic value of exhaled carbon monoxide as an early marker of exacerbation in children with chronic lung diseases.

Chronic airways infection and inflammation are leading causes of morbidity and mortality in chronic lung diseases (CLD). Pulmonary exacerbations are major causes of morbidity in CLD. Exhaled carbon monoxide (eCO) is a product of endogenous metabolic processes whose presence in exhaled breath is considered an index of inflammatory processes. Objective. To evaluate carbon monoxide (eCO) as inflammatory marker for early detection of acute exacerbation in CLD. Methods. Case control study included 40 children with CLD (twenty in exacerbation, group I and twenty in quiescent period, group II) recruited from the Chest Clinic, Children's Hospital, Ain Shams University. Twenty apparently healthy children were included as controls (group III). Results. Patients' mean age was 9.98 ± 3.29 years: 24 (60%) males and 16 (40%) females. The mean eCO level among patients during exacerbation was 5.35 ± 1.35 (ppm) compared to 2.65 ± 0.49 (ppm) in quiescent stage and 1.30 ± 0.47 (ppm) in controls. eCO cutoff value discriminating cases and control was 1.5 (ppm) (sensitivity; 100% and specificity 70%) and cutoff value discriminating group I from group II was 3 (ppm) (sensitivity: 100% and specificity: 100%). Conclusion. Exhaled CO can be considered a noninvasive early marker of acute exacerbation of CLD.