What does "PICS" mean in major burns? Persistent critical illness or post-intensive care syndrome

Patient surviving major burns affecting > 20% of their total body surface (TBSA), will experience a long intensive care (ICU) and hospital stay, with burns > 40% TBSA generally causing persistent critically illness. Persistent inflammation, immunosuppression and catabolism syndrome (PICS/PIICS) is a pathophysiological response explaining a prolonged disease state. Thereafter survivors also frequently develop the multidimensional post-intensive care syndrome (PICS) with physical, cognitive, and psychological impairments. Although they share an acronym and partly overlap in clinical expression and timing, these entities arise from different conceptual frameworks and are not interchangeable. They may however be related and overlap as persistent catabolism may lead to long term multidimensional impairments. This review highlights the transition from immediate injury to chronic metabolic, immune, physical, and psychological disturbances. The initial response is characterised by mitochondrial dysfunction, massive stress hormone dysregulation, insulin resistance, muscle wasting due to protein catabolism, and bone resorption and loss leading to osteoporosis. The hypermetabolic state persists for prolonged periods, even in smaller burns with elevated energy expenditure. Nutrition therapy is critical until recovery. Energy, protein, glucose, lipid, and micronutrient needs and delivery require metabolic monitoring and adjustment. New data show that the urea-to-creatinine ratio (UCR) might become a usefull biomarker of protein provision. Neuropsychological complications (pain, delirium, post-traumatic stress disorders) prolong the ICU and hospital stay. The threshold for the development of PIICS and PICS is around 30-40% BSA, and impacts long term outcomes, including persistent mental health and pain control issues, and delayed return to home and work. Specialized rehabilitation with multidisciplinary interventions contributes to better outcomes. Some guidance is proposed for clinical follow-up aiming at attenuating complications and facilitating transit towards the post-hospital phase.