Hannah Wunsch is a critical-care physician at Sunnybrook Health Sciences Centre and a professor at the University of Toronto. She is the author of The Autumn Ghost: How the Battle Against a Polio Epidemic Revolutionized Modern Medical Care. Intensive care units (ICUs) are the last repository of hope in hospitals. Working with the most cutting-edge medical technology, teams of individuals skilled in critical-care medicine save lives in an ICU by combining high-tech support with nursing and medical expertise. ICUs provide a place to care for those who need high-risk surgery, those who have suffered traumatic injuries, and those with overwhelming…