The aim of the present study was to identify clinical signs detective of the 
postoperative delirium at the early stage for nursing management. A total of 66 
inpatients undergoing cardiac surgery were interviewed using the Delirium Rating 
Scale (DRS) and NEECHAM Confusion Scale (NCS) preoperatively and on days 1 and 3 
postoperatively. The mean onset of delirium occurred on postoperative day 1.3. 
Development of delirium was detected early by cognitive impairments in the DRS 
subscales of perceptual disturbance, hallucination, and cognitive status, and 
the NCS subscales of attention, command, orientation, and verbal skill. These 
results suggest that assessment of cognitive status on postoperative day is an 
important strategy in the early detection of postoperative delirium.