Postoperative mental status in elderly hip surgery patients.

PURPOSE: To determine if elderly patients undergoing hip surgery became delirious postoperatively and, if so, whether age and/or time of day were related to delirium.

DESIGN: Repeated measures.

SAMPLE: A convenience sample of 70 hip surgery patients 60 years of age and older at a large Midwestern teaching hospital were studied. Patients were excluded who were unconscious, unable to hear, see, and/or verbally communicate in English. Patients were also excluded who had a known history of dementia, Alzheimer's dementia, addiction to alcohol and/or sedative hypnotics, functional psychosis, or any other psychiatric diagnosis. Of the 70 patients, 37 were female and 33 were male. Mean age of the patients was 72.9 years (S.D. = 8.13). Patients were placed into one of three groups: Group 1--age 60 to 69 years (n = 25); Group 2--age 70 to 79 years (n = 25); or Group 3--80 years and older (n = 20). The most common procedure for all groups was total hip replacement (n = 48).

METHOD: Data were collected primarily by both objective and subjective assessment of the patients. Both the Folstein's Mini Mental Status Exam (MMSE) and the NEECHAM Confusion Tool were used to collect data. Chart reviews provided additional data. Patients were assessed preoperatively to obtain baseline assessment and screen out patients with preexisting confusion. Assessments were then done once in the morning and once in the evening for 5 days following surgery.

MAIN RESEARCH CLASSIFICATIONS: Delirium, sundowning, sundown syndrome.

FINDINGS: The MMSE and NEECHAM were found to be highly correlated: Morning NEECHAM vs morning MMSE (Correlation Coefficient = .6515; p = .000), evening NEECHAM vs evening MMSE (Correlation Coefficient = .8301; p = .000). A test of repeated measures was used to examine the data. The Within factor was time, the Between factor was age, and the interaction effect was age by time of day. Dependent variables were total NEECHAM scores and total MMSE scores, in addition to total scores of these tests' subsections. An alpha level of .05 was used for all statistical tests. Age had a significant main effect on the NEECHAM (F = 7.44; p = .001) and MMSE (F = 6.04; p = .004). Time did not have a significant effect on either the MMSE (F = .00; p = .953) or the NEECHAM (F = .43; p = .513). There was no statistically significant interaction between age and time of day (NEECHAM, F = .97, p = .384 and MMSE (F = .19, p = .826). No subjects were assessed as demented per the MMSE. Only 12 episodes of acute confusion were noted using the NEECHAM.

CONCLUSION: Patients in this population rarely, if ever, became confused. The older the individual, the more likely he/she was to have confusion. Time of day was neither significant in development of delirium nor on mental status assessment scores in this population.

IMPLICATIONS FOR NURSING RESEARCH: Current research literature notes that 10% to 50% of elderly postoperative patients experience delirium. Patients who have had femoral neck fractures can experience delirium three times more than patients having nonorthopaedic surgery. This study found that delirium in hip surgery patients is rare. A study of the more subtle components of delirium such as attention and memory might reveal less obvious changes in mental status following surgery. Type of orthopaedic surgery also might impact incidence of delirium. A comparative study between elderly total knee and total hip replacement patients would be interesting. Studying patients who have emergency hip surgery related to fracture in comparison to patients having elective hip surgery for degenerative conditions might identify other etiologies for delirium following hip surgery. Fatigue rather than time of day might be studied to observe whether it has a significant impact on mental status or delirium scores.