Objective: To investigate the change in hemodynamics and its significance in preterm infants devel-oping bronchopulmonary dysplasia（BPD）. Methods: According to the diagnostic and grading criteria for BPD

59 pre-term infants who met the inclusion criteria were divided into non-BPD group with 27 infants

mild BPD group with 9 infants

moderate BPD group with 13 infants

and severe BPD group with 10 infants. A noninvasive cardiac outputmonitor was used for dynamic monitoring of hemodynamic parameters on days 1

7

and 28 after birth

and the correlation of these parameters with brain natriuretic peptide（BNP） concentration on day 28 after birth was analyzed inpreterm infants developing BPD. Results: Compared with the non-BPD group

the three BPD groups had a signifi-cant reduction in cardiac output/cardiac index（CO/CI） on days 7 and 28 after birth（P < 0.05）

and compared withthe mild and moderate BPD groups

the severe BPD group had a significant reduction in CO/CI on days 1

7

and 28 after birth（P < 0.05）

while there was no significant difference in CO/CI between the above groups at the other timepoints（P > 0.05）. Compared with the non-BPD group

the three BPD groups had a significant reduction in stoke vol-ume/stoke index（SV/SI） on days 1 and 28 after birth（P < 0.05）

and compared with the mild and moderate BPDgroups

the severe BPD group had a significant reduction in SV/SI on days 1

7

and 28 after birth（P < 0.05）

whilethere was no significant difference in SV/SI between the above groups at the other time points（P > 0.05）. Comparedwith the non-BPD group

mild BPD group

and moderate BPD group

the severe BPD group had a significant reduc-tion in left ventricular ejection time（LVET） on days 7 and 28 after birth（P < 0.05）

while there was no significant dif-ference in LVET between the above groups at the other time points（P > 0.05）. Compared with the non-BPD group

the severe BPD group had a significant increase in systolic time ratio（STR） on day 28 after birth（P < 0.05）

whilethere was no significant difference in STR between the above groups at the other time points（P > 0.05）. There wereno significant differences in heart rate

thoracic fluid content

and contractility on days 1

14

and 28 after birth be-tween the non-BPD group and the three BPD groups（P > 0.05）. Compared with the non-BPD group

the BPD grouphad a significant increase in BNP concentration on day 28 after birth（P < 0.05）

and BNP concentration was nega-tively correlated with the changes in CO/CI（r =-0.714

P < 0.05）and SV/SI（r =-0.4

P < 0.05）on day 28 afterbirth and positively correlated with the change in STR（r = 0.722

P < 0.05）. Conclusion: There are varying de-grees of hemodynamic changes in preterm infants during the development of BPD

which may lead to the change incardiac function. Dynamic monitoring of cardiac output parameters may help with early evaluation of cardiac func-tion changes in preterm infants with BPD.