An intensive care unit (ICU), also known as a critical care unit (CCU), intensive therapy unit or intensive treatment unit (ITU) is a special department of a hospital or health care facility that provides intensive care medicine.
Patients may be transferred directly to an intensive care unit from an emergency department if required, or from a ward if they rapidly deteriorate, or immediately after surgery if the surgery is very invasive and the patient is at high risk of complications.
In 1854, Florence Nightingale left for the Crimean War, where triage, 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 as a speciality. In response to a polioepidemic (where many patients required constant ventilation and surveillance), Bjørn Aage Ibsen established the first intensive care unit in Copenhagen in 1953. The first application of this idea in the United States was in 1955 by Dr. William Mosenthal, a surgeon at the Dartmouth-Hitchcock Medical Center. In the 1960s, the importance of cardiac arrhythmias as a source of morbidity and mortality in myocardial infarctions (heart attacks) was recognized. This led to the routine use of cardiac monitoring in ICUs, especially after heart attacks.
ICU Nurse attending to a patient in Baghdad, Iraq.
ICU nurses monitoring patients from a central computer station. This allows for rapid intervention should a patients condition deteriorate whilst a member of staff is not immediately at the bedside.
Nurses in a neonatial intensive care unit (NICU)
Hospitals may have ICUs that cater to a specific medical speciality or patient, such as those listed below:
Post-anesthesia care unit (PACU): Also known as the post-operative recovery unit, or recovery room, the PACU provides immediate post-op observation and stabilisation of patients following surgical operations and anesthesia. Patients are usually held in such facilities for a limited amount of time, and must meet a set physiological criteria before transfer back to a ward with a qualified nurse escort takes place. Due to high patient flow in recovery units, and owing to the bed management cycle, if a patient breaches a time frame and is too unstable to be transferred back to a ward, they are normally transferred to a high dependency unit (HDU) or post-operative critical care unit (POCCU) for closer observation.
High dependency unit (HDU): Many hospitals have a transitional high dependency unit (HDU) for patients who require close observation, treatment and nursing care that cannot be provided on a general ward, but whose care is not at a critical enough level to warrant an ICU bed. These units are also called step-down, progressive and intensive recovery units and are utilised until a patient's conditions stabilises enough to qualify them for discharge to a general ward.
Surgical Intensive Care Unit (SICU): A specialized service in larger hospitals that provides inpatient care for critically ill patients on surgical services. As opposed to other ICUs, the care is managed by surgeons trained in critical-care/trauma.
The available data suggests a relation between ICU volume and quality of care for mechanically ventilated patients. After adjustment for severity of illnesses, demographic variables, and characteristics of different ICUs (including staffing by intensivists), higher ICU staffing was significantly associated with lower ICU and hospital mortality rates. A ratio of 2 patients to 1 nurse is recommended for a medical ICU, which contrasts to the ratio of 4:1 or 5:1 typically seen on medical floors. This varies from country to country, though; e.g., in Australia and the United Kingdom most ICUs are staffed on a 2:1 basis (for High-Dependency patients who require closer monitoring or more intensive treatment than a hospital ward can offer) or on a 1:1 basis for patients requiring very intensive support and monitoring; for example, a patient on a mechanical ventilator with associated anaesthetics or sedation such as propofol, Midazolam and use of strong analgesics such as morphine, fentanyl and/or remifentanil.
In the United States, up to 20% of hospital beds can be labelled as intensive-care beds; in the United Kingdom, intensive care usually will comprise only up to 2% of total beds. This high disparity is attributed to admission of patients in the UK only when considered the most severely ill.
Intensive care is an expensive healthcare service. In the United Kingdom, the average cost of funding an intensive care unit is:
£838 per bed per day for a neonatal intensive care unit
£1,702 per bed per day for a paediatric intensive care unit
£1,328 per bed per day for an adult intensive care unit
Olson, Terrah J. Paul; Brasel, Karen J.; Redmann, Andrew J.; Alexander, G. Caleb; Schwarze, Margaret L. (January 2013). "Surgeon-Reported Conflict With Intensivists About Postoperative Goals of Care". JAMA Surgery148 (1): 29–35. doi:10.1001/jamasurgery.2013.403.