OBJECTIVE：To observe the ef fectiveness and safety of bosentan in the treatment of hypoxic pulmonary hypertension（HPH）in neonates. METHODS ：From Jan. 2014 to Mar. 2019，a total of 82 HPH neonates hospitalized in the department of neonatology of our hospital were selected as research subjects. According to whether or not receiving bosentan therapy，50 cases were included into bosentan group and 32 cases into non-bosentan group. Meanwhile ，another 25 non-HPH neonates with serum sample retention time and general information such as gestational age at birth and day age matching the HPH group were selected as the control group. All neonates with HPH were given continuous intravenous infusion of Dopamine hydrochloride injection 5 mg/（kg·min）until PASP was normal. On this basis

neonates in the bosentan group were additionally given Bosentan tablets 1 mg/kg（fed after dissolving with appropriate amount of water for injection ）for q 12 h，72 h. The relationship between serum ET- 1 levels of neonates with HPH and PASP was analyzed ，as well as PASP before and after treatment and therapeutic efficacy between bosentan and non-bosentan groups ，the changes of arterial blood gas indexes and ADR in 3 groups were compared. RESULTS ：Before treatment ，the serum ET- 1 levels of bosentan group was （164.3±115.3）pg/mL，which was significantly higher than （41.9±3.7）pg/mL of control group and positively correlated with PASP level （r＝0.864，P＜0.001）. Total response rate of bosentan group was 90.00％，which was significantly higher than 71.88％ of non-bosentan group （P＜0.05）. After 72 h of treatment ，PASP of 2 groups was decreased significantly ，compared with before treatment （P＜0.001），and the bosentan group was significantly lower than the non-bosentan group （P＜0.05）. The PaO 2，SaO2，PaCO2 and OI in 3 groups was significantly improved compared with that before treatment （P＜0.001），and the PaO 2，SaO2 and OI in the bosentan group was significantly higher than that in the non-bosentan group （P＜0.05）. During the treatment period of bosentan and within one week after drug withdrawal，there was no significant change in serum LDH ，AST，ALT and Scr levels in neonates. There was no statistically significant difference in the incidence of feeding intolerance ，anemia，reduced WBC and reduced PLT in 3 groups（P＞0.05）. CONCLUSIONS： Bosentan can improve the oxygenation status of neonates with HPH

reduce PA SP，and short-termmedication is safe. com