Winter surge management in intensive care is hampered by the annual variability in the winter surge.We aimed to develop a real-time monitoring system that could promptly identify the start, and accurately predict the end, of the winter surge in a paediatric intensive care (PIC) setting. We adapted a statistical process control method from the stock market called "Bollinger bands" that compares current levels of demand for PIC services to thresholds based on the medium term average demand.Algorithms to identify the start and end of the surge were developed for a specific PIC service: the North Thames Children's Acute Transport Service (CATS) using eight winters of data (2005-12) 3