Light and noise: objectively assessing environmental risk factors for delirium in the ICU

Recognition of delirium as a medical entity with relevance to both morbidity and mortality, especially in critically ill patients, is a relatively recent development. However, research into delirium prevention and treatment is now in focus of scientific efforts internationally. Knowledge of intensive care unit (ICU) environment as a potential modifiable risk factor for delirium is insufficient to this date. This study thus seeks to evaluate, whether potentially modifiable environmental factors, such as noise or dazzling, are associated with development of delirium. Knowledge derived from this investigation could change both the process of care provision in intensive care units as well as the design of ICUs in general in the future. This project is planned to be carried out as an observational pilot study at three perioperative ICUs at the University Medical Centre Graz. Adult patients shall be screened for inclusion, if not deeply sedated. Suitable patients shall be included into the study after written informed consent or deferred consent if they can be expected to remain in the ICU for at least another two days, if they are not already in delirium, if the ICU environment is not actively modified for therapeutic reasons and if no treatment limitations are in place. Over a study duration of one year, 250 to 300 patients are expected to be enrolled into the study. Of those, 60 to 120 patients are likely to develop delirium. Baseline data known to be of relevance for outcome prediction in critically ill patients and factors known to predispose for development of delirium during ICU and hospital stay will be collected. Study equipment will be deployed to measure noise levels and illumination repeatedly over the day. Daily assessments for delirium using the Confusion Assessment Method in Intensive Care Units (CAM-ICU) will be performed. Vital status, physiologic parameters and parameters of ongoing treatment will concomitantly be documented on a daily basis. Data on light and noise levels are then to be unified with parameters of physiology and treatment, vital status, and results of daily assessments for delirium. Statistical analysis using methods of descriptive and comparative statistics as well as both unadjusted and adjusted logistic regression analysis will be performed to identify factors significantly associated with the development of delirium (i.e., risk factors).