RESUMO
AIMS AND OBJECTIVES: To evaluate the ductal diameter centiles in the first 24 h of life and their relation to cerebral blood flow in neonates weighing <1250 g in the first 24 h of life. METHOD AND MATERIAL: This prospective observational cohort study enrolled 44 infants with birth weight <1250 g. Two-dimensional echocardiography and color Doppler were performed within the first 12 h of life and were repeated again in the next 12 h of life to assess the ductal size and middle cerebral artery (MCA) flows [peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (MV) and pulsatility index (PI)]. RESULTS: The mean patent ductus arteriosus (PDA) size (mm) within 0-6 h was 1.88 ± 1.12, within 7-12 h was 2.02 ± 0.973, within 13-18 h was 1.47 ± 1.00 and within 19-24 h was 1.42 ± 0.705. There was a significant increase in the PSV and MV of the MCA in infants with open PDA compared with those with closed PDA (p < 0.05) when measured between 13 and 24 h of life. There was no correlation between the PDA size and simultaneous PSV, EDV, MV and PI of MCA within 12 h of life. The PDA size within 13-24 h showed correlation with only the PSV of the MCA (p = 0.05) and not with the EDV, MV and PI. There was no significant difference in the PSV, EDV, MV and PI among the infants depending on the size of the PDA. CONCLUSION: There is a progressive decrease in the PDA size in the first 24 h of life. The PSV and MV of the MCA are increased in infants with closed PDA, but among those with open PDA, size does not relate to MCA flows in the first 24 h of life.