1. Department of Critical Care Medicine and Anesthesia, Hospital for Sick Children, University of Toronto, Toronto, Canada
2. Department of Anesthesiology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
3. Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada; and
4. Department of Critical Care Medicine, Sunnybrook Health Sciences Centre, Toronto, Canada