1. Department of Anesthesia, Critical Care, and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
2. Adult Intensive Care Unit, Queen Mary Hospital, Hong Kong SAR, China
3. Brigham and Women's Hospital Heart and Vascular Center, Harvard Medical School, Boston, Massachusetts
4. Cardiac Medical Unit, Grantham Hospital, Hong Kong SAR, China
5. Department of Anesthesia, Critical Care, and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
6. Neurovascular Research Laboratory, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts