A paediatric intensive care unit (also known as Paediatric ICU) is a section of a hospital dedicated to the treatment of severely ill infants, children, teenagers, and young adults aged 0 to 21. A paediatric intensive care unit (PICU) is often led by one or more paediatric intensivists or PICU consultants and staffed by doctors, nurses, and respiratory therapists who have received additional training and experience in paediatric critical care. Nurse practitioners, physician assistants, physiotherapists, social workers, child life specialists, and clerks may also work on the unit, though this varies greatly depending on geographic region. Because of the acuity of PICU patients and the potential of life-threatening complications, the ratio of experts to patients is often higher than in other parts of the hospital. Complex technology and equipment, such as mechanical ventilators and patient monitoring systems, are frequently used.