A post-operative delirium is defined as attentional, consciousness and perceptual deficit occurring after and as a consequence of an operation. These deficits are acute and severe, but usually reversible. A post-operative cognitive dysfunction (POCD) is a serious impediment to cognitive functioning, affecting memory, learning, and cognition, again occurring after and as a consequence of an operation. Both delirium and POCD, of which delirium is predictive, have been recognized in medical science as being associated with major cardiac surgery for a while. However, its prevalence after non-cardiac surgery and its links to mortality have only been quantified relatively recently. These studies show that delirium and POCD are very frequent post-operative complications that often go unrecognized. The prevalence across different age groups varies: younger (18-39) adults and older (60+) adults seem to be particularly at risk of developing early POCD (i.e., POCD at hospital discharge) with one study reporting 36.6% of younger and 41,4% of older adults being affected, as compared to the middle-aged (40-59), 30.4% of which were affected. Late POCD (i.e., POCD three months after hospital discharge) was found to be significantly more common in older adults (12.7%) than in the younger or middle aged population (5.7% and 5.6%, respectively). In intensive care settings, delirium is estimated to occur in up to 82% of patients, POCD in up to 41%.

Importantly, delirium as well as POCD are associated with significant negative effects on health: Investigators report a 1-year mortality rate post-discharge of 10.2% for patients with late POCD. Investigators conducted a meta-analysis of post-discharge mortality, institutionalization and dementia amongst elderly patients and found a 38.0% risk of death for patients with delirium by the time of a 2-year follow-up, compared to a control group with 27.5%; a 33.4% probability of institutionalization a year later as compared to 10.7% in the control; and a 62.5% chance of developing dementia up to 4 years later as compared to 8.1% in the control. These differences were independent of confounders such as age, sex, comorbidity, illness severity, and baseline dementia scores. Other studies report prolonged cognitive impairment over 12 months after surgery and significantly higher rates of job loss associated with POCD.

Note that delirium and POCD are complications that can be managed very well. There are relatively simple ways to prevent delirium or recover from it more quickly. Importantly, patients themselves can do a great deal in the way of preparation for an operation and post-operative behavior to significantly reduce their likelihood of getting delirium / POCD or manage it successfully. Yet, most patients are only made aware of the issue, if at all, during their pre-operative anesthetic consultation, usually the evening before the operation - too late to put many of the important preparatory behaviours into place. Importantly, there is no direct communication channel between general practitioners, who refer the patient, and clinical anesthesiologists who deal with delirium / POCD management. Thus, risk factors for as well as incidence of delirium / POCD after surgeries are likely not passed between these important actors in the health system.

Given its high prevalence and serious impact on mental health, physical health, and socio-economic factors, it is imperative that patients and general practitioners alike are aware of delirium / POCD as well as how to recognize it, how to best prepare for an operation in order to reduce its chance of occurrence, and how to behave in case post-operative delirium or POCD has developed. To the knowledge of the investigators, this is the first study to date assessing the awareness of delirium / POCD, their respective risk factors and effective preparation and treatment options in a pre-clinical sample of the general population. Goal of the study is to assess and quantify the current communication deficit in the healthcare system and thus build up pressure to improve it.