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Second Opinion - Anesthesia & the elderly

Lauren Langford, MD

A commonly heard statement about elderly patients is they are "just not the same" after surgery. Are confusion, forgetfulness and even delusions related to the major stresses of illness, surgery itself, or the things that make being hospitalized so unpleasant - poor sleep, restricted movement and a regimen of medicines?
Much is unknown about the cognitive effects of anesthesia, especially in the elderly, but cognitive dysfunction is a well-established phenomenon associated with cardiopulmonary bypass surgery. Recent research shows it to be a surprisingly common event after other types of major surgery. There is no strong evidence that the problems are associated with particular drugs.
Over the past 10 years, physicians have discovered two factors that increase the chances a patient would become dramatically confused after an operation - being older than about 70 years and having preexisting mental deficits, such as regularly forgetting appointments or severe dementia.
Among patients above age 60 years about half become seriously disoriented after heart bypass or valve replacement surgery, in contrast to only 15 percent or so of patients in the same age range who had elective hip joint surgery - a shorter and less risky procedure. In general, the more anesthesia someone receives and, consequently, the deeper someone slips into unconsciousness, the greater the risk for cognitive decline.
Delirium - alteration of consciousness - is common in hospitalized elderly patients. Visual hallucinations, delusional thoughts, anxiety and distress can occur in a diurnal variation leading to a mistaken diagnosis of depression.
Delirium I, more common after major surgeries, can last at least a few hours and require patients to stay one night or longer in the hospital. Just admission to a hospital increases risk for cognitive decline in elderly patients. Day surgery is often recommended for patients who have adequate support consisting of competent relatives, home nurses and social services.
One frequently asked question concerns the association of dementia onset and surgery. Anesthesia does not appear to increase the risk of developing dementia. It seems that there is a subset of the elderly population that stands atop a slippery slope making them vulnerable to prolonged or permanent cognitive decline if they receive anesthesia. These patients may be genetically predisposed to dementia or have other risk factors.
At present, it is not possible to identify which patients are a high risk or which parts of the hospitalization process - anesthesia, surgery or postoperative care - may be causing the deterioration. It is the task of all the physicians, family and all involved to discuss the issue of possible cognitive decline of the patient.
For some patients and some procedures, consideration of these risks may lead to the conclusion that the proposed surgery is not in the best interest of the patient.
For your elderly loved ones who must have surgery, provide the anesthesiologist with as much medical history information as possible. Discuss prior illnesses and hospitalizations, past surgery and current treatments.
For patients of all ages, the time leading up to surgery is a great time to focus on being as healthy as possible. The healthier you are prior to undergoing surgery and anesthesia, the more likely you will have a smooth recovery. Depression is common in elders and has been associated with cognitive difficulties following surgery. It's important that patients are treated for depression prior to undergoing surgery.
While in the hospital, ask a family member to stay in the hospital room to orient and comfort the patient. Make a special request to keep the anesthesia as light as possible. Ask for perioperative brain monitoring which can help avoid too much anesthesia and postoperative dementia by allowing the doctor to know exactly how much of the drug is needed.
Although elders are at higher risk, general anesthesia is overall very safe. Most people, even those with significant health conditions, are able to undergo general anesthesia itself without serious problems.
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