Abstract: Objective To observe the effects of nitric oxide ( NO) inhalation on the cardiac function of the burn patients with inhalation injury. Methods Twelve burn patients with moderate degree of inhalation injury were enrolled in the study and randomly divided into control group ( C, six cases with conventional therapy) and treatment group( T, six cases with conventional therapy and NO inhalation of 10 ppm). Swan-Ganz catheters were placed in all of the patients. The changes in the indices of the cardiac function and plasma contents of endothelin (ET) and NO in the patients in both groups were measured before treatment time and 6, 12, 24, 48 and 72 hours after treatment ( HAT). The changes in the plasma contents of ET and NO in the T group were analyzed correlatively. Results Both the cardiac output (CO) and stroke volume (SV) in the T group were significantly higher than the normal values at 24 HAT ( P < 0.05 , P < 0.01),and the ineredse occurred earlier than those in control group ( P < 0.05). The improvement in LVSWI and RVSWI in T group was observed earlier than those in C group. There was evident difference of RVSWI between T and C groups( P <0.01). The plasma content of ET decreased significantly, while the NO content increased dramatically in T group compared with those in C group ( P <0.01). Conclusion The cardiac function of the patients with inhalation injury could be improved by NO inhalation of 10ppm, which might be related to the regulation of the tension of the pulmonary vascular smooth muscle by NO.