Central venous catheterization is, now, one of the most routinely used procedures in the NICUs, helping during the care of very sick infants. Pericardial effusion is a very rare but severe complication, with a high mortality. The cases described are part of an ongoing retrospective study where the use of central catheters inserted in our surgical NICU, and its complications is being analyzed. 16 cases over 13 years are presented in this article, varying in severity from mild, self-resolving cases that were discovered during routine cardiac POCUS to cases with important hemodynamic impact associated with cardiac tamponade and cardiac arrest. Due to immediate intervention, only one of the cases led to catheter-related mortality and that was under particular conditions. Our aim is to highlight the severity of this complication, the importance of early intervention, and the impact of a highly technologized unit and widely available cardiac POCUS.