study of prevention of postoperative delirum to reduce incidence of postoperative cognitive dysfunction

Conditions: Postoperative Cognitive Dysfunction; Postoperative Delirium

Summary: postoperative cognitive dysfunction describes a condition where cognitive functions such as attention, perception, concentration, learning, abstract thinking and problem solving are impaired postoperatively. these changes can be resolved after weeks and months, but in some cases may be permanent. the aetiology is multifactorial. one risk factor for developing pocd is the occurrence of postoperative delirium. a total of 638 consecutive patients will be enrolled in the study. patients will be followed up at 7 days, 3 months and 1 year postoperatively. the cognitive function will be tested and compared to tests done before surgery. postoperatively (from the day of operation until the 7th day and except of day 6) the grade of sedation; agitation; signs of delirium; pain; cardiac; respiratory; renal and infectious complications will be recorded. as possible influencing factors, the investigators will document diagnosed depression; comorbidities; intraoperative blood loss; length of hospital stay; 1-year-mortality; number of operations/anaesthetics undergone after the initial operation. parameters that could trigger either depressive symptoms, neurocognitive dysfunction, anxiety, fatigue or lack of concentration will be recorded. these include: anaemia, hypercalcaemia, thyroidal gland hormones, electrolytes, creatinine, urea, glomerular filtration rate, cortisone therapy and adrenal cortical insufficiency.

the methods include a neuropsychological test battery: tap 2.3 (attention), trail making test (tmt )a+b (attention), digit span (memory), (visual learning and memory test (vlmt) (memory), regensburgerwortfluessigkeitstest/fluency (rwt) subtests (executive function), mehrfach-wortschatz-intelligenztest/vocabulary (mwt-b) (premorbid iq). other measures are hospital anxiety and depression scale (hads-d) (depressive symptoms and anxiety), mini mental state examination (mmse) 2 (dementia), confusion assessment method (cam-icu) (delirium), richmond agitation and sedation scale (rass) (sedation and agitation), numeric rating scale (nrs) (pain) and short form health survey (sf-12) (health related quality of life).

Eligibility criteria:
inclusion criteria: * age \> 60 years * cardiac surgery (on-pump/off-pump, standard/minimal invasive) * written informed patient's consent exclusion criteria: * non-german speaking or not their first language * illiteracy * mental disability * non-corrigible vision impairment * non-corrigible hearing impairment * illegal substance abuse (current or past history) * alcohol abuse (current or past history) * chronic benzodiazepine use * psychosis (current or past history) * parkinson disease * dementia * multiple sclerosis * epilepsy (current or past history) * cerebral tumor (current or past history) * apoplexy or intracranial bleeding (current or past history) * severe traumatic brain injury (current or past history) * severe liver disease (child pugh b, c, liver insufficiency) * severe kidney disease with dialysis * mini mental status examination \< 24 points