Normal Reference Ranges for Pulmonary Artery Diameters in Preterm Infants.

To establish normal reference ranges and Z-scores for pulmonary artery diameters in preterm infants and their correlation with body surface area, body weight, and chronological age. In a prospective study, 268 preterm infants, who fulfilled the inclusion criteria were examined. Echocardiograms were performed to measure the main pulmonary artery, right pulmonary artery, and left pulmonary artery diameters on day(s) 0 to -6 of life and at weekly intervals until they reached 36 weeks of age. Body surface area was divided into thirteen groups from 0.07 to 0.19 m. The mean gestational age was 29.8 (±2.38 SD) weeks, ranging between 24 and 35, the mean body weight was 1479 (±413 SD) grams, ranging between 588 and 3380, and the mean body surface area was 0.13 m, ranging between 0.07 and 0.19 m. All the pulmonary artery diameters correlated well with both body weight and body surface area. Reference ranges, with mean ± SD, range, and Z-scores for aortic diameters according to body surface area were calculated. A significant gradual increase was observed in main and branch pulmonary artery diameters with increasing body surface area. Overall, a progressive and significant increase for main and branch pulmonary artery diameters was observed during the first nine weeks of life. The main and branch pulmonary artery diameters were found to have significant correlation with body surface area. The study also provides reference data with Z-scores, which can be used as a normal reference tool for measuring the main pulmonary artery, right, and left pulmonary artery diameters of preterm infants against body surface area.