The history and rationale of daily and nightly hemodialysis.

Quotidian is an adjective that has come into use recently to describe more frequent hemodialysis. However, it would seem appropriate to use the more descriptive terms daily and nightly hemodialysis to describe the time of day that more frequent dialysis is performed. Nightly is to be preferred to ‘nocturnal’ as three times weekly overnight hemodialysis (also nocturnal) has been a conventional form of treatment since 1964, albeit used by only a small number of patients in recent years. The dictionary definition of quotidian is ‘occurring every day’ or ‘belonging to each day,’ but also includes ‘commonplace’ or ‘ordinary’. For the foreseeable future, more frequent dialysis will hardly be either commonplace or ordinary. With regard to the history of quotidian dialysis, a brief review has recently been described [1].