DISTURBED CIRCADIAN REST-ACTIVITY PATTERNS IN DELIRIUM AFTER CARDIAC SURGERY

Delirium Rating Scale-Revised-98 (DRS-r98), 5 or on medical file reports of clinicians or nurses regarding episodes of extreme restlessness of the patient. However, objective and quantitative data of normalization of circadian rest-activity patterns of patients following elective cardiac surgery is lacking, let alone of patients who develop a delirium after cardiac surgery. Wrist-actigraphy can be used as an objective method to assess 24-hr patterns of spontaneous motor activity for prolonged periods of time in various environments. The method accurately distinguishes rest from activity periods in a valid and reliable way. 6,7 Considering the clinical importance of disturbed circadian rest-activity patterns in delirium after cardiac surgery, clarification of its role has relevance for diagnostic purposes, for early recognition of subtypes of delirium which may improve prognosis by early treatment, and for the development of effective treatment strategies. Therefore, we performed an observational study to explore the usefulness of wrist-actigraphy to quantify characteristics of 24-hr motor activity patterns during a 5-day post-operative period after elective cardiac surgery in patients who did or did not develop a delirium. As a first approach, we focused on the duration of the delirium in relation to recovery of circadian rest-activity patterns.