Authors: (including presenting author): :
Cheng MW(1), Yip OC(1)
Affiliation: :
(1) Cluster Planning and Commissioning Team, Princess Margaret Hospital
Introduction: :
The vulnerable patients staying in a constant environment is common characteristic in hospital setting. Artificial light illuminates both days and nights with the same intensity and spectrum, constant temperature, humidity and 24-hr patient care interaction, patients may be at risk disruption of their circadian rhythm continuously. This study introduced innovative methods for circadian lighting design and explored how the application might promote the environmental supports for patient restorative process.
Objectives: :
(1) To compare patients’ hospitalization experience; and (2) to compare the potential efficacy, on circadian and traditional lighting design.
Methodology: :
Comprehensive literature review was conducted to explore (1) the effect of hospital lighting in a relationship with patients' experience and sleep quality; (2) other implication such as energy efficiency, environmental issue, costing and international standards.
Result & Outcome: :
Six full text studies in English from 1999 to 2015 were obtained related to lighting and its effect on patient's health outcomes. Primary outcomes showed dynamic lighting environment favorable to positive patients’ experience. Bernhofer (2013) study concluded low light exposure hospital inversely associated with higher fatigue (r = -0.31, p< 0.05), mood disturbance (r= -0.34, p< 0.05) which positively correlated with higher pain level (r = 0.34, p< 0.05). On the contrary, a qualitative study showed cycled lighting environment helped patient reduce anxiety and improve sense of security (Engwall, 2015). Although factors influencing sleep quality is multifactorial and not limited to circadian rhythm, nocturnal rise of serum melatonin level had been detected with a marked improvement in sleep and an alleviation of behavior disturbance in demented patients (Ohashi, 1999). Melatonin is one of the humoral mediators participates in sleep-wake rhythm regulation. On the other words, low plasma melatonin amplitude showed higher risk of delirum in ICU setting (Barroso, 2011). Optimal light from 6 to 10 hours light stimulus with around 8 hours of darkness boosted the amplitude of melatonin level (Barroso, 2013; Bernhofer, 2013). Also, risk of delirium had been reduced for critical patient in ICU setting (Madrid-Navarro, 2015) as a secondary outcome. Despite the cost of using circadian lighting system will be 25% higher, a life-cycle cost analysis should be undertaken taking proper account of potential productivity gains from increased daylight, as well as the likely maintenance costs, which are likely to be lower with hybrid systems. Hybrid lighting system combines natural day lighting system and circadian LED lighting solution can reduce daytime artificial light by 50%.
