1) Please declare any conflicts of interest below: The authors declare a potential conflict of interest but not a personal conflict of interest. Part of the costs for this study are covered by Heartcentre Twente Foundation. Prolira provided training and the DeltaScans during the study period free of charge and applied a discount to the disposable patch costs. 2) Ethics Approval: Ethical approval was waived by the Advisory committee Medisch Spectrum Twente at Enschede. The Institutional Review Board of Medisch Spectrum Twente has concluded that this study does not fall under the remit of the Medical Research Involving Human Subjects. 3) Context: The study was done on the cardiothoracic surgery ward at Thoraxcentrum Twente (Medisch Spectrum Twente, Enschede, the Netherlands), a tertiary teaching hospital. Patients 70 years or older who underwent cardiac surgery were included. The quality improvement team included nurse practitioners in cardiac surgery and psychiatry, a cardiac surgeon, nurses, a technical physician, and an epidemiologist. 4) Problem: Delirium is a common syndrome of acute brain failure, which often occurs in hospitalized older patients following cardiac surgery. Delirium after cardiac surgery is related to adverse long-term outcomes, more readmissions to hospital, and decreased cognitive and functional outcomes. Early detection of delirium allows early treatment of underlying causes. In standard care, we use a delirium observation scale score (DOSS). Recently, a single-channel electroencephalography (EEG) medical device was developed to screen delirium based on detection of delta waves (DeltaScan). Using DeltaScan in routine care may improve delirium detection and clinical outcomes. 5) Assessment of problem and analysis of its causes: Previous delirium studies in Thoraxcentrum Twente using DOSS as standard care reported an incidence of delirium of 13 to 17% in elective patients aged ≥45 years. Published and unpublished research data for cardiothoracic surgery wards show an increase of delirium detection by >15% (absolute percentage growth), when DeltaScan was used in clinical studies. Nurses, nurse practitioners, and medical doctors were informed about the aims of the study and importance of delirium screening. A nurse improvement project, including a workgroup, was started, where the importance of screening was emphasized. Before the implementation of the DeltaScan, nurses on the surgical ward received education and training. Medical doctors, residents, and nurse practitioners were trained on how to interpret the DeltaScan scores. 6) Intervention: First, we continued the DOSS as regular care for delirium screening; three measurements a day for the first three postoperative days. Second, DeltaScan was implemented as new regular care. DeltaScan measurements took place twice a day for at least three consecutive days. 7) Strategy for change: In February 2021 additional training of the DOSS for delirium screening began, and from April 2021 onwards, prospective data collection of the first group continued till May 2022. Training with DeltaScan started in March/April 2022. The DeltaScan data collection started in May 2022, and is still ongoing. 8) Measurement of improvement: The primary endpoints to measure improvement were incidence of delirium, and length of hospital stay. Secondary endpoints included delirium duration, adherence to delirium protocol, and costs related to the innovation. The innovation was deemed successful with an incidence increase from 15 to 30%, and a length of stay reduction with at least 1.5 days. This abstract is based on preliminary data until October 2022. 9) Effects of changes: In total 612 patients were included, with 450 patients in the DOSS group and 162 patients (interim results) in the DeltaScan group. Incidence of finding delirium increased from 15% to 25% (p = 0.008). Median length of hospital stay for delirium patients was reduced from 9 hospital nights to 5.5 nights (p = 0.002). Median duration of delirium decreased (not significantly) from 77 hours to 65 hours (p = 0.12). 10) Lessons learned: Involving all stakeholders early in the project helped to gain commitment to the innovation. The change was measured in a scientific study, as no formal results on effectivity are known at the moment. Introducing a new device for delirium screening arouses resistance. Reducing or removing this resistance remains difficult. 11) Messages for others: Involving all stakeholders in a working group for delirium screening helped to start an innovation, monitor benefits, and motivated colleagues to actually commit to the innovation. Screening for delirium with DeltaScan in our study leads to an increase of finding delirium, and reduced hospital stay (interim results) for patients after cardiothoracic surgery. It is unknown yet, whether this is cost-effective. We hypothesize that these results are expected to be similar for other patient groups such as geriatric or general surgical patients. 12) Please describe how you have involved patients, carers, or family members in the project: Patients and their relatives are informed about the risk of delirium and the impact of delirium before hospital admission. Relatives and patients are often informed during measurements on the importance of adequate delirium screening, where positive responses are often heard. No formal co-creation by patients was done, but informal feedback will be collected in the near future. </p