It is recognized that there is difficulty with mental functioning after surgery in the elderly, according to an article in the June 2003 issue of Clinical Anesthesiology. It now has an official name, which is post-operative cognitive dysfunction. It is sometimes called POCD. There is limited knowledge on how to predict it and reduce its risk. Local anethesia can have the same or worse effects as general anesthesia. It has some similarities to other dementias. It has a number of differences as well.
Dementia is a chronic, progressive decrease in the functioning of the brain. The most evident feature is short-term memory loss. Dementia involves other cognitive function problems such as inappropriate behavior, poor judgment, and inability to learn and communicate, think clearly and keep safe. It may be the result of a number of medical conditions, the most common of which is Alzheimer’s disease. The symptoms of dementia most often get worse over time, rather than coming on suddenly after an event such as surgery.
Post Operative Cognitive Dysfunction
Post-operative cognitive dysfunction is a decline in cognitive function that lasts for weeks or months after surgery. It is important because those with it have an increased risk of disease or death. Patients with post-operative cognitive dysfunction at their hospital discharge have a better than average chance of dying in the first three months after surgery, and those with POCD at both discharge and three months are more likely to die in the first year after surgery than those with no POCD, according to an article in the January issue of the journal Anesthesiology. Most people recover from uncomplicated post-operative cognitive dysfunction. Persons do not recover from dementia unless it is caused by a treatable condition.
People who are in the early stages of undiagnosed dementia may be more vulnerable to developing post-operative cognitive dysfunction because there are already changes going on in their brain. Most likely they will be diagnosed with dementia in the future. The trauma of undergoing surgery can bring pre-existing cognitive decline to the forefront. It does not cause the dementia, according to an update sheet from 2007 from Alzheimer’s Australia. There is a lot of interest in trying to determine the causes of POCD and how it can be minimized.
Diagnosis And Risks
A person who may have POCD is given a group of neuropsychological tests. Different areas of mental functioning are tested. These tests may include: word learning, word recall, cognitive flexibility, distractibility and memory. Recognizing POCD means that these patients can be watched so that further damage will be minimized.
It seems that those undergoing heart surgery are more likely to suffer from POCD. Problems in mental functioning are seen in non-heart surgery patients as well. POCD is more common in elderly patients and occurs after surgery that is major. Patients with post traumatic stress disorder seem to be at a greater risk for developing POCD.
There is no single cause of POCD, or altered mental functioning after anesthesia and surgery. It could be due to the residual effects of anesthesia or the sedatives, and painkillers that are used before and after surgery. Narcotics and sedative drugs can result in confusion in the elderly and should be given in low doses or not given at all if post-operative cognitive dysfunction is suspected. Ventilation may cause problems in the prefrontal area of the brain. Surgery also may cause changes in metabolism, which could lead to POCD.