Background
Illnesses that necessitate intensive care can impair cognitive function severely over the long term, leaving patients less able to cope with the demands of everyday living and markedly lowering their quality of life. There has not yet been any comprehensive study of the cognitive sequelae of critical illness among non-surgical patients treated in intensive care. The purpose of this review is to present the available study findings on cognitive deficits in such patients, with particular attention to prevalence, types of deficit, clinical course, risk factors, prevention, and treatment.
Methods
This review is based on pertinent publications retrieved by a selective search in MEDLINE.
Results
The literature search yielded 3360 hits, among which there were 14 studies that met our inclusion criteria. 17–78% of patients had cognitive deficits after discharge from the intensive care unit; most had never had a cognitive deficit before. Cognitive impairment often persisted for up to several years after discharge (0.5 to 9 years) and tended to improve over time. The only definite risk factor is delirium.
Conclusion
Cognitive dysfunction is a common sequela of the treatment of non-surgical patients in intensive care units. It is a serious problem for the affected persons and an increasingly important socio-economic problem as well. The effective management of delirium is very important. General conclusions are hard to draw from the available data because of heterogeneous study designs, varying methods of measurement, and differences among patient cohorts. Further studies are needed so that study designs and clinical testing procedures can be standardized and effective measures for prevention and treatment can be identified.