Objective: To study the relationship between plasmic nitric oxide (NO), endothelin-1 (ET-1) levels and occurrence of hepatopulmonary syndrome (HPS) in liver cirrhosis with portal hypertension (LCPH) patients.
Methods: Fifty-two LCPH patients were divided into group Ⅰ（with HPS） and  groupⅡ (without HPS). Plasmic NO and  ET-1 levels were detected by nitric acid reductase and radioimmunoassay (RIA) respectively.
Results: Occurrence of HPS in all patients was 11.5%（6/52）, and was 30% (3/10) in Child-Pugh class C patients. In group Ⅰ, 50% (3/6) patients were in Child-Pugh class C. The comparison showed that plasmic NO levels were significantly higher in group Ⅰ than that in group Ⅱ［(110.40±28.02)μmol/L vs. (79.56±22.12)μmol/L, P＜0.01］, but there was no significant difference in ET-1 levels（P＞0.05）.
Conclusions: Elevated plasmic NO levels is an important characteristic of HPS, and, when combined with Child-Pugh classification, it can be significant for diagnosis of HPS in LCPH patients.