An intensive care unit (ICU), critical care unit (CCU), intensive therapy unit/intensive treatment unit (ITU) or High Dependency Unit (HDU) is a specialized department in a hospital that provides intensive-care medicine. Many hospitals also have designated intensive care areas for certain specialties of medicine, depending on the needs and resources of the hospital.
In 1854, Florence Nightingale left for the Crimean War, where triage was used to separate seriously wounded soldiers from the less-seriously wounded was observed. Until recently, it was reported that Nightingale reduced mortality from 40% to 2% on the battlefield. Although this was not the case, her experiences during the war formed the foundation for her later discovery of the importance of sanitary conditions in hospitals, a critical component of intensive care.
In 1950, anesthesiologistPeter Safar established the concept of "Advanced Support of Life," keeping patients sedated and ventilated in an intensive care environment. Safar is considered to be the first practitioner of intensive-care medicine.