Study of the relationship between indoor daylight environments and patient average length of stay (ALOS) in healthcare facilities

Abstract

This study investigates how indoor daylight environments affect patient Average Length of Stay (ALOS), by evaluating and analyzing daylight levels in patient rooms in comparison to their ALOS. The patient ALOS data were taken at one general hospital in Inchon, Korea and the other in Bryan, Texas, U.S.A.; physical, environmental and daylighting conditions were assessed at each building site. The gathered data were analyzed using SPSS statistical package to determine the trends in patients’ length of stay in hospital wards with 95% and 90% statistical significances. The data were categorized based on the orientation of a patient room and were compared between different orientations and types of patient rooms in the same ward of each hospital. Selected hospital wards were classified based on their orientations and types of patient rooms. The other variables considered in the study were: the differences in daylighting environments (illuminance, luminance ration, daylight factor, diversity and uniformity of illuminance), and physical environment properties of the patient rooms of each hospital, and how these affected patient ALOS in both locations (Inchon and Bryan). To analyze the daylighting environment, on-site measurements, RADIANCE simulations and physical scale model measurements were conducted. This study also investigated patients’ feelings and opinions, and their preferences in daylighting environments with the questionnaire survey. Through this study, three hypotheses were tested and was evidence for the following conclusions. First, there may be a positive relationship between indoor daylight environments and ALOS. Second, seasonal weather differences cause different indoor daylighting levels and may influence the length of patient hospitalization. Third, overall patient satisfaction and reactions to patient rooms may be related with indoor daylight environments. More controllable shading devices, naturally lighted indoor environments, and glare prevention create positive outcomes for patient ALOS and visual comfort. To increase the validity and confidence about the positive effects of daylight on human physiological conditions, further studies are necessary which provide more samples, facilities and other variables. This study was created as a basis for the development of recommendations for designing patient rooms in healthcare facilities and, as a result, should be used to achieve more effective healing environments.