Effect of Fluid Bolus on Inferior Vena Cava Dynamics and Left Ventricular Output in Newborns

Objective To evaluate the effect of a fluid bolus on inferior vena cava dynamics and left ventricular output in newborns. Methods This prospective, analytical study enrolled newborns in a tertiary neonatal intensive care unit (NICU) who needed a fluid bolus based on clinical assessment. Inferior vena cava (IVC) collapsibility/distensibility and left ventricular output (LVO) were measured using ultrasound before and after a 10 mL/kg normal saline bolus. Results Sixty newborns were included in the study [room air ( n = 21), continuous positive airway pressure (CPAP) ( n = 12), and ventilated ( n = 27)]. Significant reductions in IVC collapsibility were observed in the room air group ( P < .001), while IVC distensibility significantly decreased in both CPAP ( P = .002) and ventilated ( P < .001) groups. Volume time integral (VTI) and LVO increased significantly following a fluid bolus in all the groups. Clinical parameters showed minimal changes, except for a significant improvement in capillary refill time in the ventilated group. Conclusion IVC collapsibility/distensibility, VTI, and LVO demonstrate significant improvements after a fluid bolus, suggesting point-of-care ultrasound may be a valuable tool for guiding fluid management in the NICU, although changes in clinical parameters were not always concordant.