BRAIN HEALTH FOLLOWING SURGERY AND ANAESTHESIA FOR OLDER PEOPLE. Immediately following surgery with an anaesthetic older people may become temporarily confused – suffering from ‘delirium’. Up to 65% of older patients may develop postoperative delirium of varying degrees. Once this confusion has cleared, which may take many months, most recover fully but some may continue to show signs of deteriorated cognitive function (especially learning/memory and executive functions) or even clear-cut dementia. Some older people will show signs of deteriorated cognitive function after surgery and anaesthetic without having any or obvious delirium. This continuing long term cognitive deterioration may occur in up to 10% of older people having surgery with anaesthesia. The anaesthetic alone does not appear to be fully responsible for these problems. Older people who already have some cognitive problems are particularly likely to suffer delirium and further deterioration with surgery and anaesthetic.
There are two possible explanations for this (both of which may be valid). First, many of the people who develop delirium and/or subsequent cognitive decline already have brain changes associated with disorders such as Alzheimer’s disease or Dementia with Lewy Bodies and the surgery/anaesthetic acts as a ‘stress test’. The second possibility is that the surgery and anaesthesia contributes to increased brain pathology via neuroinflammation or by some other mechanism.
It is worth noting that people experiencing Dementia with Lewy Bodies can very easily develop delirium.
These observations, in any case, provide a strong argument, in relation to anaesthesia and surgery for older people:
(1) to avoid non-essential procedures and examine the balance of risk in any decision about procedures. This should obviously involve discussion with the person themselves and where appropriate their family or carers.
(2) to assess each older person before surgery, sometimes including baseline cognitive testing.
(3) to ensure that hospitals accept, understand, prepare for and provide optimal staff, services and appropriately designed facilities to manage postoperative delirium.
(4) to provide informed follow-up for people who develop delirium postoperatively to ensure that any ongoing cognitive problems are addressed, investigated and managed. In Australia this follow-up could be in the hands of General Practitioners. This follow-up should include attention to support and education for families and carers.
Very recent detailed discussion:
https://pubmed.ncbi.nlm.nih.gov/34338712/
2019 detailed discussion:
State of the clinical science of perioperative brain health: report from the American Society of Anesthesiologists Brain Health Initiative Summit 2018 (bjanaesthesia.org)
Chapter 12 in my book discusses delirium, including postoperative delirium