A majority of PICU survivors seem to have unchanged functional health and good QoL. In the reviewed studies, functional health is evaluated by telephone interviews [27, 38, 47, 65] . In most of these studies, the physician rather than the child or its parents evaluates functional health. Ideal (HR)QoL questionnaires should measure all aspects of QoL and preferably be filled in by the children themselves. Proxy investigation of functional health and (HR) QoL (in children <6-8 years of age) is second best [36, 37, 39, 66] . Besides, the pre-morbid state is probably an important factor which is difficult to assess [16] .