ArticlesLong-term postoperative cognitive dysfunction in the elderly: ISPOCD1 study
Introduction
Early postoperative cognitive dysfunction, confusion, and delirium are common after major surgery in the elderly.1, 2 Previous studies and anecdotal reports suggest that symptoms may persist in some patients for months or years.3 Events such as anaesthesia may contribute to agerelated cognitive decline, even when they occurred many years previously.4 Long-term postoperative cognitive dysfunction can occur after cardiac surgery, but the cause was thought to be the cardiopulmonary bypass.5, 6 The prevalence, causes, risk factors, and consequences of long-term postoperative cognitive dysfunction after non-cardiac surgery are unknown.
The monitoring of oxygen saturation has shown that hypoxaemia is most severe during nights 2 and 3 after surgery.7 Studies to characterise risk factors, to identify the deleterious effects of hypoxaemia on the heart, brain, and other organs, and to clarify the influence of hypoxaemia on outcome after surgery have been called for.8
In a multicentre study (the International Study of Post-Operative Cognitive Dysfunction [ISPOCD 1]), we investigated the occurrence of long-term postoperative cognitive dysfunction in elderly patients after major abdominal and orthopaedic surgery. We assessed the role of age as a major risk factor, and the causative roles of hypoxaemia and hypotension.
Section snippets
Methods
The protocol was approved by the research ethics committees in the centres and all patients gave written informed consent.
13 hospitals in eight European countries and the USA recruited patients to the study by the same protocol. Eligible patients were aged at least 60 years, had presented for major abdominal, non-cardiac thoracic, or orthopaedic surgery under general anaesthesia between Nov 1, 1994, and May 31, 1996, and expected a hospital stay of at least 4 days. We gave priority to patients
Results
We enrolled 176 UK controls, 145 national controls and 1218 patients. 271 (22%) patients did not complete the assessment at 3 months because of refusal to participate (118) and death (57). Those who withdrew did not differ significantly in any characteristics from those who continued in the study. The age, sex distribution, and other characteristics of the patients and the UK controls were similar (table 1).
At 7 days (5th-95th percentile 4–19) after surgery, we found cognitive dysfunction in
Discussion
We confirmed unequivocally that anaesthesia and surgery cause long-term postoperative cognitive decline in the elderly and that the risk increases with age. However, neither hypoxaemia nor hypotension was related to the risk. We were unable to find any specific risk factors to which therapeutic or preventive measures could be directed and we could not elucidate the pathophysiology of postoperative cognitive dysfunction any clearer.
Cerebral hypoxia can lead to severe brain damage, but the degree
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