In this issue of Thorax Navaet al review the provision of respiratory intensive and high dependency care in Europe.1 Medically orientated high dependency units (HDUs) are rare in the UK and in a recent survey only 26% of 190 general hospitals with an intensive care unit (ICU) had an HDU2; the proportion of beds allocated for medical patients was not stated. With increasing pressure on intensive care beds and the development of non-invasive ventilation, it is timely to consider the provision of a clinical area intermediate between intensive care and a general medical ward. Common sense suggests that, if the choice is between an ICU—with one nurse to each patient and a high level of monitoring—and a general ward—with a much lower nurse:patient ratio and little or no monitoring equipment—patients will either need to remain in the ICU longer than is necessary or be discharged to the ward earlier than is ideal.

However, we live in an era of evidence based medicine and business cases. A recent Medical Research Council/Department of Health Working Party paper3 highlighted the fact that little hard evidence exists, in the form of clinical controlled trials, to prove that HDU (or ICU) care is effective or even cost effective. This makes it difficult to argue for increasing provision of these facilities or to decide on the best way to organise this type of care. There are some persuasive financial and organisational arguments in favour of the establishment of HDUs. Significant financial savings could be made by caring for some proportion of the current ICU population in an HDU. A number of studies indicate that a significant proportion (23–33%) of ICU beds are occupied by patients who …