Pediatric Critical Care (PCC) is a constantly evolving and complex specialty with a heterogenous patient population. In this field, there are many important topics, therapies, interventions, treatments, and diseases that we need to understand or understand better. Research is vital to achieving this aim. Despite the increasing number of clinical studies and trials in critically ill children, there is still much we need to find out. This chapter uses one common clinical scenario to examine some of the issues we need to understand better through research. Finally, it is also important to understand and consider what our users, the children, and the parents, think that we need to know to help them. These problems must be examined through a multidisciplinary lens, with studies led by a multidisciplinary (multiprofessional) healthcare team.