1 Project Summary Pediatric Intensive Care Unit (PICU) survival has increased substantially over the past three decades, rendering mortality alone an insufficient metric for pediatric critical illness outcomes assessment. Currently, a comprehensive understanding of PICU morbidity and the trajectory of recovery among PICU survivors and their families is limited. Post-intensive care syndrome (PICS) consists of new or worsening impairments in physical, cognitive, or mental health status that arise and may persist after critical illness. The characteristics of PICS in children (PICS-p) are unknown. At this time, we cannot identify modifiable risk factors for poor PICU outcomes and/or develop systematic, timely, and targeted PICU or post-PICU interventions to improve PICU morbidity without first understanding the recovery in children who commonly share the PICU experience. Here, we propose a prospective longitudinal cohort study of patients undergoing >3 days of ICU therapies (case) at one of 20 US PICUs to evaluate child and family outcomes over two years. We will compare outcomes of these PICU patients with a control group of patients who received an overnight (control) PICU stay who did not receive intensive care unit therapies as well as with published quality of life data from the general and chronically ill populations. Children and their families will be enrolled locally from each PICU, and their outcomes will be followed centrally from the University of Pennsylvania and Seattle Children’s Research Institute. Our specific aims are (1) to determine the physical, cognitive, emotional, and social health outcomes and trajectory of recovery in a population of children post-critical illness; (2) to determine the baseline health, presenting problem, and PICU factors associated with impaired physical, cognitive, emotional, and social outcomes among PICU survivors, and (3) to determine the emotional and social health outcomes in parents and siblings of PICU survivors. Our primary goal is to explicate the impact of pediatric critical illness over a two-year period of time to guide future intervention research to optimize child and family outcomes. Our overall goal is to improve the health and well-being of PICU survivors and their families. 1