Critical care evolved from an historical recognition that the needs of patients with acute, life-threatening illness or injury could be better treated if they were grouped into specific areas of the hospital. Nurses have long recognized that very sick patients receive more attention if they are located near the nursing station.

• Florence Nightingale wrote about the advantages of establishing a separate area of the hospital for patients recovering from surgery.
• Intensive care began in the United States when Dr. W.E. Dandy opens a three-bed unit for postoperative neurosurgical patients at the Johns Hopkins Hospital in Baltimore.
  In 1927, the first hospital premature-born infant care center was established at the Sarah Morris Hospital in Chicago.
• During World War II, shock wards were established to resuscitate and care for soldiers injured in battle or undergoing surgery.
• The nursing shortage, which followed World War II, forced the grouping of postoperative patients in recovery rooms to ensure attentive care. The obvious benefits in improved patient care resulted in the spread of recovery rooms to nearly every hospital by 1960.
• In 1947-1948, the polio epidemic raged through Europe and the United States, resulting in a breakthrough in the treatment of patients dying from respiratory paralysis. In Denmark, manual ventilation was accomplished through a tube placed in the trachea of polio patients. Patients with respiratory paralysis and/or suffering from acute circulatory failure required intensive nursing care.
• During the 1950s, the development of mechanical ventilation led to the organization of respiratory intensive care units (ICUs) in many European and American hospitals. The care and monitoring of mechanically ventilated patients proved to be more efficient when patients were grouped in a single location. General ICUs for very sick patients, including postoperative patients, were developed for the similar reasons.
• Johns Hopkins Bayview Medical Center became the first multidisciplinary intensive care unit (ICU) in the United States.  Created in 1958 at Baltimore City Hospitals, now Johns Hopkins Bayview, this first multidisciplinary ICU in the country led the way for optimal medical and nursing care to critically ill patients 24 hours a day.  It was also the first ICU covered by an in-house physician (anesthesia resident) 24/7.
• By the late 1960s, most United States hospitals had at least one ICU.
• In 1970, 28 physicians with a major interest in the care of the critically ill and injured met in Los Angeles, California to discuss the formation of an organization committed to meeting the needs of critical care patients: the Society of Critical Care Medicine (SCCM).
• In 1986, the American Board of Medical Specialties approved a certification of special competence in critical care for the four primary boards: anesthesiology, internal medicine, pediatrics, and surgery.
• Between 1990 and the present, critical care significantly reduced in-hospital time as well as costs incurred by patients with diseases such as cerebrovascular insufficiency and respiratory failure.
  • The development of new and complicated surgical procedures, such as transplantation of the liver, lung, hearts, small intestine, and pancreas, created a new and important role for critical care following transplantation.
  • Widespread utilization of non-invasive patient monitoring has further reduced the cost and medical/nursing complications, such as infection, associated with care of critically ill and injured patients.
  • Widespread utilization of pharmacologic therapy for critical care patients with specific organ system failure reduced time spent in both critical care units and in the health care facility.
• In 1997, more than 5,000 ICUs were operational in intensive care units across the United States.