Bright light treatment for prevention of perioperative delirium in elderly patients

Background: Bright light treatment aims to improve circadian rhythms in patients living indoors with poor light-dark transitions by complementing insufficient natural light and highlighting the difference between their day- and night-time activities. In addition to bright light treatment, it is called "phototherapy" or "high-intensity light therapy", and has been reported to be effective to prevent delirium and sleep disorders in the elderly. Under such circumstances, this study examined the validity of bright light treatment as a perioperative care approach for the elderly who are regarded as vulnerable to delirium due to hospitalization or therapeutic intervention. Methods: The study was conducted in the mixed surgical ward of approximately 200 beds, located in Kyoto Prefecture. Subjects were elderly male and female patients who underwent surgery for lower limbs, mainly the femur, and were randomly divided into intervention and control groups. The intervention group received bright light treatment with approximately 2,500 lx of bright light from the day after admission; on the day of surgery and at postoperative week 1, while the control group was treated with normal light during this period. The evaluation of delirium was conducted based on the results of nurses' observation and the Japanese-Version NEECHAM Confusion Scale (NEECHAM scale). In addition to this, information regarding the patients' activities of daily living was also collected. As physiological indices, light-exposure-dependent changes in blood serotonin levels and stress-dependent changes in blood cortisol levels were also evaluated. The period of the study was between 2008 and 2010; data were collected from November to February in each year, when the number of target patients increased. Results: As a result, data regarding 24 patients were obtained within this 2-year period. Excluding those with severe dementia, a total of 16 (intervention: 6; and control: 10) were studied. As a result, delirium occurred in the patients who underwent surgery of the lower limbs, mainly the femur, within the period between the day of surgery and postoperative day 3. The type of delirium was hyperactive in all cases, and its symptoms persisted for 3 to 4 days. Conclusion: The incidence of delirium was generally lower in the intervention than in the control group, suggesting the validity of bright light treatment.