Objective To explore the changes of plasma endothelin (ET) and nitric oxide (NO) levels in children with acute pneumonia.

Methods The level of plasma ET was measured by radioactive immunoassay, and NO by spectrophotometry. Statistical analysis was performed with the Wilcoxon test.

Results The levels of ET, NO and the ET/NO ratio in children with acute pneumonia (AP). with in 24 hours in hospital were all significantly higher than those in other groups of patients ((140±4.2) pg/ml, (104±7.1) μmol/L, and 1.67±0.11, P<0.01). Compared to healthy controls (N), the levels of ET and NO in children increased significantly (P<0.01).

Compared with those before treatment, the levels of ET and NO in the SP group on the 3rd and 7th day in hospital dropped significantly (P<0.01). The ET/NO ratio on the 7th day was also lower than that on admission (P<0.01).

Conclusions The malfunction of endothelial cells and the increased ET/NO ratio may be related to the mechanism of acute pneumonia microcirculatory disturbance in patients with AP; early dynamic determination of these parameters may help predict the prognosis of AP.