A High Dependency Unit (HDU) is an area in a hospital, usually located close to the Intensive Care Unit (ICU), where patients can be cared for more extensively than on a normal ward, but not to the point of intensive care. Patients may be admitted to an HDU bed because they are at risk of requiring intensive care admission, or as a step-down between intensive care and ward-based care. HDUs are appropriate for patients who have had major surgery and for those with single-organ failure. Many hospitals use HDUs in different ways, some people are admitted before and after planned surgery, and many who are admitted to ICU as emergencies are moved to HDU immediately after leaving intensive care. The main difference between intensive care and high dependency care is the nurse to patient ratio. Usually, an ICU patient requires one-to-one nursing care, while a high dependency patient requires one nurse for every two patients.