With old people | Duration of the side effects and after-effects of anaesthesia

With old people

The side effects of anaesthesia can be manifold. Post-operative pain, nausea and vomiting after an anaesthetic, as well as states of confusion occur most frequently. Older patients in particular often suffer from a so-called postoperative delirium.

According to various studies, between 30 and 40 percent of all over-60s are affected by this phenomenon, which is also called transitional syndrome. The patients suffer from hallucinations, often do not recognise their relatives and suffer from a strong disorientation. This causes strong fear in some patients and can lead to aggression.

The time of onset of this side effect as well as its duration can vary greatly. Above all, the duration of the anaesthesia, as well as the patient’s concomitant diseases, such as diabetes or high blood pressure, play a role. On average, about 40 percent of all over 60-year-olds suffer from a cognitive deficit immediately after discharge from hospital.

Even three months after the operation, 12 percent of them are still affected by confusion and increased forgetfulness. As a rule, these after-effects of anaesthesia are not permanent. Only in a few cases does long-term damage to brain tissue occur in older patients. A connection between the postoperative delirium and the development of dementia is still being discussed.

At the eyes

Some patients describe symptoms in their eyes after waking up from anesthesia. These include visual field failures, which are usually described by those affected as “blackening before the eyes” or bright flashes in the visual field. In fact, however, there is no known direct effect of anaesthesia on the function of the eyes or the nerves and brain areas associated with them.

The blackening in front of the eyes is rather due to a drop in blood pressure as a result of the anaesthetic medication, which results in a short-term reduction in blood flow to the retina. However, this phenomenon usually does not last longer than a few seconds and is harmless. It can be counteracted very well with a sufficient fluid intake and above all bed rest.

A second consequence of anaesthesia, the appearance of bright flashes in the field of vision, is often described as an ocular migraine. The reason for this term is its presumed cause, which resembles that of a “real” migraine. This is probably also the reason for a vasospasm, the cramp-like narrowing of blood vessels.

Especially arteries that supply the visual cortex in the rear section of the cerebrum seem to be affected. This phenomenon is also usually self-limiting and disappears after a short time. A connection to anaesthesia has not been proven here either.