Psychiatria pre prax 2/2009

Early and late cognitive dysfunction after General anaesthesia

General anaesthesia is sometimes called a „controlled coma“, as indexed by four features: (1) the lack of motor response to instructions; (2) suppression of autonomic and skeletal responses to intra operative stimuli such as incisions; (3) absence of retrospective awareness of pain; and (4) postoperative amnesia for surgical procedures such as conversations among the medical staff. The anaesthetized patients generally are insensitive to stimuli of any kind, do not dream, have no sense of the passage of time, and generally awake with their consciousness completely unaffected with no memory of events during the surgical procedure. The deterioration in cognitive function after general anaesthesia appears as: delirium and Post Operative Cognitive Dysfunction (POCD) and further. Delirium usually occurs during the first postoperative days as an acute, fluctuating condition. The patient has lost orientation and has impairment of attention and memory MCI (mild cognitive impairment) – light cognitive dysfunction. Post Operative Cognitive Dysfunction (POCD). It is present for weeks or months postoperatively and it resembles dementia but in most cases the deficits are not so pronounced. Accordingly, this disorder is easily overlooked and it is difficult to evaluate. Dementia – heavy deficit including deterioration emotionality and social insertion. Risk factors are general anaesthetics but also brain hypoxia caused by arterial hypoxaemia or low flow. Finally, psychological factors related to illness and environment during hospitalisation may be important. Age is the most important risk factor.

Keywords: anaesthesia, delirium PODC, brain, age, surgery