Neonatology Fellow The Warren Alpert Medical School of Brown University Maine Medical Center Providence, Rhode Island, United States
Background: UVCs often migrate out of initial position, but the factors contributing to line migration have not been well characterized. Malpositioned UVCs pose rare but severe risks to infants, including pericardial effusion, tamponade, arrhythmia, and liver hematoma. However, UVC position is not routinely monitored following initial placement in most NICUs. Objective: To investigate UVC migration by serially monitoring line position with point of care ultrasound (POCUS), and to explore how type of respiratory support and change in abdominal circumference may impact line migration. Design/Methods: This is a prospective study of infants admitted to the NICU of any weight and gestational age who required placement of a UVC. Line position was monitored with POCUS using standard cardiac views. Data from infants who had at least two ultrasounds performed one or more days apart were included. Logistic/linear modeling adjusting for multiple scans was performed. Results: A total of 30 infants and 77 scans were included. The median gestational age and birth weight were 28.2 weeks and 1.1 kg, respectively. Line migration by >0.2 cm was observed in 65% of UVCs, with observed migration distance ranging from 1.75 cm downward to 1.1 cm upward. Among infants on CPAP, 44% had line migration downward, compared to 20% of other infants (OR 3.4, CI [-0.92,12.3], p=0.067). Interestingly, 75% of infants with clinical “CPAP belly” had downward migration of their UVC (p=0.009). In contrast, intubated infants were more likely to experience upward line migration (40%) compared to other infants (21%; OR 2.6, CI [-0.59, 11.0], p=0.2). Of note, infants not on respiratory support were the most likely to have stable UVC position over time without migration (71%). Infants with an increased abdominal circumference were 5.3 times more likely to experience downward line migration compared to other infants (CI [1.27, 22.0], p=0.02), whereas infants with a decreased abdominal circumference were 7.6 times more likely to experience upward line migration (CI [1.93, 29.5], p=0.003). For each cm/kg increase in abdominal circumference, 0.14 cm of downward line migration was observed (p=0.005).
Conclusion(s): These data suggest that amount and direction of UVC migration are related to type of respiratory support and changes in abdominal circumference. Our results provide novel information on the factors contributing to UVC migration and emphasize the importance of frequent monitoring of line tip position using ultrasound.
