Duration of side effects and after effects of anesthesia


The duration of side effects and after effects of anesthesia depend on many factors. In addition to age, the anesthetic agent used also plays a role. Most postoperative symptoms, such as nausea or mild confusion, are basically short-lived.


If no preventive measures are taken, up to 30% of all patients under general anesthesia suffer from what is known as PONV.
This abbreviation stands for the English term "postoperative nausea and vomiting", translated into German as postoperative nausea and vomiting.
PONV is caused by several factors. These include, among other things, the choice of anesthetic drug, personal disposition, but also the patient's lifestyle. As a result, the extent and duration of this more than unpleasant side effect of anesthesia is very individual.
Risk factors for developing postoperative nausea include the female gender and the young age of the patient (6 to 16 year olds are affected significantly more often). Furthermore, the likelihood of developing nausea during long operations and a tendency to motion sickness is higher. Non-smokers also suffer from PONV about twice as often as smokers.

If left untreated, nausea as an aftereffect of an operation usually lasts for a few hours. Fortunately, well-proven treatment options for post-operative nausea are available. These include antiemetics, which are drugs against nausea such as Vomex or metoclopramide.
What is more important, however, is adequate prevention, which can significantly reduce the risk of nausea after surgery. This should especially be done if there are several risk factors. For prophylaxis, dexamethasone or the aforementioned antiemetics can be administered at the beginning of the operation.

Read more on the topic:

  • PONV
  • Aftermath of general anesthesia

Forgetfulness / confusion

In addition to pain and nausea, confusion or forgetfulness after anesthesia is the most common consequence of long operations.

Slight states of confusion and increased forgetfulness directly after waking are harmless and occur in almost all patients. They are simply due to the residual anesthetic that remains in the body, which will affect the functioning of the brain for some time. Usually, however, the confusion should subside after a few minutes to hours. However, it is not all that rare that brain function is impaired even after a long period of time.
In the age group of 18 to 59 year olds, around 30 percent of all patients still suffer from cognitive disorders even after they have been discharged from hospital. This phenomenon is called "postoperative cognitive deficit" (abbreviated POCD). The severity of this cognitive deficit can vary widely and range from slight concentration disorders to severe disorientation.
The duration of confusion is just as different. One study found that about five percent of patients are still affected after three months. In older patients, the proportion of those still suffering from confusion and forgetfulness after three months is even higher at 12 percent. Fortunately, in almost all cases these symptoms are self-limiting. An improvement will gradually be noticeable.

With old people

The side effects of anesthesia can be varied. Postoperative pain, nausea and vomiting after anesthesia, as well as states of confusion are the most common occurrences.
Older patients in particular often suffer from so-called postoperative delirium. According to various studies, between 30 and 40 percent of all over 60-year-olds are affected by this phenomenon, which is also known as transit syndrome. The patients suffer from hallucinations, often do not recognize their relatives and suffer from severe disorientation. This creates great anxiety in some patients and can lead to aggression.
The time at which this side effect starts, as well as its duration, can vary widely. Above all, the duration of the anesthesia, as well as concomitant diseases of the patient, such as diabetes or high blood pressure, play a role.
On average, around 40 percent of all people over the age of 60 suffer from a cognitive deficit immediately after their discharge from hospital.Even three months after the operation, 12 percent of them are still affected by states of confusion and increased forgetfulness. As a rule, these after-effects of the anesthesia are not permanent. Only in a few cases does long-term damage to the brain tissue occur in older patients. A connection between postoperative delirium and the development of dementia is still being discussed.

Read more on the topic: postoperative delirium.

In the eyes

Some patients describe symptoms of the eyes after awakening from anesthesia. This includes Visual field loss which are mostly described by those affected as "turning black in front of the eyes" or as light ones Lightning bolts in the field of vision.
In fact, however no direct effect of anesthesia known on the function of the eyes or the nerves and brain areas associated with them.
Rather, the blackness in front of the eyes is on you Drop in blood pressure due to the anesthetic medication, which is a short-term Reduced blood flow to the retina has the consequence. However, this phenomenon usually does not last longer than a few seconds and is harmless. With adequate hydration and especially bed rest, can be counteracted very well.
A second consequence of anesthesia, which is not uncommonly described, is the appearance of bright flashes in the field of vision, which is often described as eye migraine.
The reason for this name lies in its suspected cause, which is similar to that of a "real" migraine. So here too there is likely to be a vascular spasm, i.e. the spasmodic narrowing of blood vessels. Arteries in particular, which supply the visual cortex in the rear section of the cerebrum, appear to be affected. This phenomenon is also common self-limiting and disappears after a short time. A connection to anesthesia has not been proven here either.