Objective To evaluate the value of monitoring non-invasive cardiac outputparameters in medical treatment of patent ductus arteriosus (PDA) in premature infants.MethodPremature infants with PDA diagnosed three days after birth (gestational age28 ~ 31 weeks or birth weight of 1 000 ~ 1 799 g) admitted to the neonatal intensive care unit (NICU) of our Hospital from February 2016 to August 2016 were enrolled in the study.These premature infants were assigned into treated PDA group (the treatment group) and untreated PDA group (the observation group) based on results of non-invasive cardiac outputparameters CI and MD,with aorta CI ≥2.95 L/(min · m2),MD ≥21.50 m/min and pulmonary artery CI ≥4.55 L/(min · m2),MD ≥26.50 m/min as cut-off values.Statistical analysis was carried out using t test,x2 test.The closure rate of arterial duct of two groups and changes in non-invasive cardiac outputparameters before and after the closure of arterial duct in the treatment group were compared.Result The overall closure rate of arterial duct was 85.1% (57/67).The closure rate of arterial duct of the treatment group was 70.8% (17/24),that of the observation group was 93.0% (40/43),and the difference had statistical significance (P < 0.05);Comparing the following parameters before and after ductal closure in the treatment group,the difference of pulmonary artery flow time (FT),aortastroke volume index (SVI) and the integral of the flow profile (Vti) had statistical significance (P < 0.05) [(217.6±19.3) ms vs.(235.8 ±21.4) ms,(22.4±6.0)ml/m2 vs.(25.2 ±7.7)ml/m2,(15.1 ± 4.1) cm vs.(17.2 ±5.3) cm].In the treatment group,after arterial duct was closed,aorta and pulmonary artery CI,MD decreased to some degree,but the difference had no statistical significance (P > 0.05).Conclusion Non-invasive cardiac outputparameters including aorta and pulmonary artery CI,MD have certain guiding significance for PDA drugtreatment among premature infants;after PDA drugtreatment,arterial duct closure condition cannot be judged simply by the changes of aorta and pulmonary artery CI,MD,ultrasonic cardiogram examination results should also be considered.