Integration of inferior vena cava measurements into routine functional echocardiography in preterm neonates. Are We There Yet?

Objective: To evaluate baseline inferior vena cava measurements and investigate the clinical factors that may affect inferior vena cava diameters and hemodynamic changes during the first week of life in preterm neonates.

Study design: This prospective observational study included a consecutive cohort of 30 preterm neonates born at < 34 weeks gestation. Echocardiographic parameters and inferior vena cava diameters were measured on postnatal 1st, 3rd, and 7th days, and inferior vena cava indices were calculated.

Results: Significant changes in inferior vena cava parameters were observed during the first postnatal week. The median inferior vena cava maximum diameter increased from 2.77 [2.36-3.33] mm on the 1st day to 3.09 [2.59-3.47] mm on the 3rd day, then decreased to 2.63 [2.32-3.27] mm on the 7th day (p: 0.048). The median inferior vena cava indices, including collapsibility, distensibility, and respiratory variation indices, were 22.24%, 28.61%, and 25.02% on the 1st day, respectively. These indices peaked on day 3 (26.20%, 35.51%, and 30.15%, respectively) before decreasing by day 7 (21.45%, 27.33%, and 24.03%, respectively) (p: 0.034 for all indices).

Conclusion: This study reported baseline inferior vena cava parameters in preterm neonates during the first week of life. These inferior vena cava parameters might be integrated into routine hemodynamic assessment to determine preload and intravascular volume status. Further studies with larger samples are needed to assess inferior vena cava parameters in preterm neonates more accurately and reliably.