Acute confusional states in patients undergoing hip surgery. a prospective observation study

There is general agreement that acute confusional state (ACS) is common among elderly patients admitted to hospital, although exact figures are difficult to obtain. The objective of the current study was to investigate the onset of ACS during hospital stay and to isolate possible predisposing, facilitating and precipitating factors associated with the onset of ACS.

Non-confused patients, greater than or = 65 years of age, undergoing orthopedic hip surgery, were consecutively included in the study (n = 225). Of these, 149 patients were operated on because of acute hip fracture and 76 underwent elective hip-replacement surgery. ACS was diagnosed by the DSM-IV criteria for delirium. Structured observations of ACS onset were performed every 2nd to every 4th hour during the patients' entire hospital stay. A protocol was used to document the observations on sleep, activities, well being and behavior. The Mini-Mental State Examination was used to measure cognitive functioning.

Of 225 patients 20% were diagnosed with ACS. The incidence of ACS was 24.3% in the group of hip-fractured patients and 11.7% in the hip-replacement surgery patients. The onset of ACS was postoperative (mean 24 +/- 21 h after surgery) in all but 8 patients. The duration of ACS among recovered patients was generally less than 48 h (mean 42 +/- 43 h). Predisposing factors were older age, cognitive impairment and pre-existing cerebrovascular or other brain diseases. Facilitating factors related to ACS were associated with communication and social isolation, e.g. impaired hearing and sight, reticence and passivity. One precipitating factor, besides surgery, may be the use of psychopharmacological drugs.

The incidence of ACS was 20% among hip surgery patients. Older age and social isolation were factors associated with ACS. Increased attention and interaction with older patients could be of value in avoiding ACS during hospitalization.