Light adapted to time of day improves ICU patients’ health

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With light adapted to the time of day, health even improves for intensive care unit (ICU) patients who are barely conscious when they are admitted for care, found Swedish research.

The light environment in intensive care affects how patients feel – even a year after completed hospitalisation.

“It is really important with a normal circadian rhythm and light is the environmental factor that has the greatest affect,” says Marie Engwall, doctoral student in Health and Care Sciences at the Sahlgrenska Academy and assistant lecturer at University of Borås, with a background as an ambulance nurse anaesthetist.

Her research is about severely ill or injured patients who are admitted for intensive care, initially often an anaesthetised state and in a hospital environment where investigations and treatments must be able to operate around the clock.

Many patients are confused and lost with regards to what day it is, and this is where light comes in. In order to counterbalance the traditional ICU department with low levels of daylight and nights when lighting is frequently turned on, and experimental environment with so-called cyclical lighting that changed during the day into fourteen different light scenarios.

Mornings began with a weak, reddish dawn light, which, at around 8 am turned to a strong, blue light similar to daylight. In the middle of the day, the strength of the light was reduced slightly so that patients would also be able to experience existing daylight to subsequently be increased again in the afternoon.

Towards the evening, the light became weaker and warmer again. At that time, the light sources were also placed at a lower height; in the evening only a weak and warm light was emitted from the skirting boards. All this to resemble natural light throughout the day.

“The patients were very satisfied with the lighting environment. It had a calming function and helped in supporting the circadian rhythm, Earlier research shows that it is very important with a stable circadian rhythm for hormonal levels and other physiological function in the body,” says Engwall.

The survey that was conducted 6 months after discharge did not provide any clear picture of the recovery of the patients. Engvall describes this time as a fragile period for many of them. However, after another 6 months there was a different tune when the same on hundred patients were once again asked about the physical and mental health, appetite and sleep.

“Patients cared for in our experimental room demonstrated significantly better self-rated recovery after twelve months compared to patients in the control group. I do no claim that everything is a result of the light, but there is an indication and a clear finding here that we can continue working with,” says Engwall.

Her research focuses on the patient but even the impressions of healthy visitors evaluated in a questionnaire gave positive results. Staff were not consulted in the studies in question, but nevertheless, Engwall has received some response during the course of the process.

“They really like the light that provides good working light during the day. At night time, the levels are lower than what they are used to in order for patients to be able to sleep better,” she says.

Aim: The overall aim of this thesis was to describe and evaluate patients’, who were cared for in the intensive care unit (ICU), experiences and effects concerning a cycled lighting intervention based on health, wellbeing and recovery.
Methods: An automatically controlled cycled lighting intervention aimed to mimic natural light levels, quality and position throughout the day was evaluated. An ordinary lit room was used as a control. A multiple-method approach was used. In study I, there were three aspects: a systematic review of the previous research concerning cycled lighting interventions in the intensive care; visitor evaluations of the lighting environments in the intervention and ordinary room; and measurements of illuminance, luminance and irradiance in both conditions. In study II, the patients evaluated the lighting environment in the two rooms. Data were compared and analysed. Furthermore, patients’ experiences regarding the cycled lighting environment were investigated through qualitative interviews, which were subsequently analysed by content analysis. In study III, patients’ sleep, activity and physiological parameters were measured and compared. Study IV consisted of statistical analysis of a questionnaire concerning patients’ self-reported recovery six and 12 months after their ICU treatments.
Results: The literature review on cycled lighting interventions in adult ICUs was rare but more common in the neonatal ICU (NICU). Findings showed that cycled lighting interventions improved health in preterm infants, but there were also non-significant results reported. The visitors reported the cycled lighting environment as more pleasant, and based on measurements, the lighting levels were at equivalent levels with European recommendations for hospitals. The lighting levels in the ordinary room were manually controlled and were reported as being either too low or too bright during the daytime. Patients evaluated the cycled lighting environment as brighter in daytime, and this was in coherence with the results from the measurements of illumination. Patients’ individual experiences concerning the cycled lighting environment were reported in four categories: a dynamic lighting environment, the impact of lighting on patients’ sleep, the impact of light/lighting on the circadian rhythm and the degree to which the lighting calmed them. Patients’ circadian rhythms were not further strengthened by the cycled lighting intervention during their final 24-period in the ICU. Twelve months after their ICU treatments, patients cared for in the intervention environment self-reported their recovery as significantly better than those who received treatment in the ordinary room.
Conclusions: A multiple methodology was used to explore the research field from a wider perspective. Combining knowledge from both the lighting research field and caring science has brought new knowledge to both and especially to the practice of nursing. Despite their severe illnesses or injuries, patients were able to assess their experiences with the lighting environment and reflect on how the lighting was able to support their health. This thesis reports findings that indicate that environmental/lighting interventions may improve patients’ health. Lighting interventions are harmless, safe, sustainable and, in comparison to technical and medical interventions, considerably cheaper. With this knowledge, we believe all vulnerable patients in the ICU should be surrounded by a lighting environment around the clock to support their health, wellbeing and recovery.

University of Gothenburg material
Thesis link

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