On the bright side of life - The effect of ambient light intensity on postsurgical patient-reported outcomes

Light intensity affects humans in multi ple ways. We aimed to characterise the potential impact of light intensity on patients' pain management experience in the postoperative setting. Within the German multicentre registry project QUIPS, we collected patient - reported outcomes (PROs) concerning pain and side effects, demographics and periope rative pain medication, and measured the light intensity in their rooms on the first postoperative day. Primary endpoint was the maximum pain intensity rated on the numerical rating scale (NRS, 0 - 10). Secondary endpoints were pain inten sity during movement, mood, nausea, tiredness and satisfaction. Measurement of light intensity was done with a calib rated light meter. For analysis, we used linear and log linear regression models with age, gender, preexisting chronic pain, ASA status, and logarithmised light intensity as independent variables. Data of 539 surgical patients from 9 hospitals were included. We found no significant effect of light intensity on the primary endpoint. However, we observed a strong positive correlation between nausea and light intensity.