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Direct sunlight and ventilator weaning outcomes

Originally Published:
Key Point Summary
Key Point Summary Author(s):
Zborowsky, Terri
Key Concepts/Context

Research shows that room design and the healthcare environment offer physical and psychological benefits for patients and others. For example, windows, by providing views of nature and exposure to sun, offer beneficial effects. Attention restoration theory posits that viewing a natural scene promotes a feeling of being away from it all and allows for a mental recuperative break. This change in cognitive functioning promoted by nature offers recuperative powers. An alternative psychological-based explanation is that people have evolved an immediate noncognitive stress-reduction reaction to nature. These psychological theories do not go so far as to specify the physical mechanism by which sunlight operates, but it does appear that nature provides positive feelings in anticipation of recuperation.

With that in mind, the authors of this article studied patients on mechanical ventilation. These patients present the medical community with housing needs, high-costs, and risks of prolonged institutionalization. Therefore, getting these patients off ventilator support more quickly could reduce costs and risks. They hypothesized that patients in rooms with windows offering more direct sunlight would demonstrate faster ventilator-weaning outcomes than those assigned to rooms with windows that provided less direct sunlight.


The purpose of this study was to explore the relationship between nature views and the ability to successfully wean from a ventilator.


The article reports on the results of a 2-year study, with no interventions, on the outcomes of 72 mechanical ventilator-dependent patients on one floor of an 80-bed, long-term, acute care facility in an urban area in the Southeast. Patients were randomly assigned to their rooms.

The study included all adult patients being weaned from mechanical ventilation from January 2, 2008, to January 1, 2010. (Weaning patients off the ventilator is the process of helping them breathe independently from the ventilator machine.) Of these patients, 72 were found suitable for the study. The researchers retrieved the data from these patients from an electronic length-of-stay (days of ventilation) database and cross-referenced them with a paper copy of daily work assignments.

Every patient had a private room with a large window. Half the beds faced away from the main
nurses’ station and half faced toward it. All rooms and windows were similar, except for bed and window orientation. The investigators measured the rooms when they were empty to estimate the distance of the bed to the window, window size, and wall size. They also noted what kind of views, such as foliage, were accessible for each room.

Bed distances and window measurements were approximate. Windows were 1 m off the floor and 2.7 m to 3.4 m away from the beds. Window sizes were approximately 1 m by 1.2 m, taking up 30% of a 1.5 m by 2.4 m wall. The windows had adjustable shades between double-paned glass panels. Views from the windows were unobstructed and viewable even for patients who were lying down. All windows were in within the patients’ line of sight, either on their left or right side. To decrease ventilator-associated pneumonia, the hospital’s policy is that ventilator-assisted patients have their head above bed at least 30 degrees, which increased the patient’s field of view. Every window had a view of at least two medium-sized deciduous trees in an urban setting.

The same two pulmonologists provided all the patients’ primary medical care. The weaning process continued 24 hours a day, which demanded around-the-clock coverage by a medical doctor, nursing, respiratory therapy, laboratory staff, and x-ray technicians. Constant monitoring provided immediate feedback to nurses and others on the patients’ health status. An onsite physician is necessary because patients are at risk of dying while on mechanical ventilation. Patients who fail to wean may require specialized long-term institutional care.

Design Implications
It is not simply the direction the window faces but the time of year that must considered to maximize direct sunlight for patients. This measurement scheme for sunlight also seems to make confounds less likely to be a problem for the results since there was no specific room, direction, or side of the building that was predicted to be best for patient recovery.Probably the biggest qualification of these results is the fact that they are correlational. There appears to be a meaningful relationship, but without a true experiment, it’s not possible to say that the direct sunlight was what actually caused any effect. 

According to the results of this study, direct sunlight significantly predicted the number of days to wean from the ventilator (β = −0.135, P < .05). The more direct sunlight the patient experienced, the fewer days of weaning were needed. Researchers analyzed models including demographic variables and interaction terms, but they found none to be significant.

The authors note that the results do not shed any light on the mechanism behind the sunlight effect..


The authors note that their results are only directly applicable to the population included in the analyses. This study did not include the sickest patients because they were sent to the ICU, therefore, the results cannot be applied to patients in a similar condition.

Reviewer note: As the authors state, the exact mechanism in the view/sunlight exposure was not identified in this study. It would be hard to apply these findings to other settings since the exact cause is still unknown.

Design Category
Room configuration and layout
Outcome Category
Patient / resident health outcomes
Key Point Summary Author(s):
Zborowsky, Terri
Primary Author
Wise, P. M.