Very rare risks

The following risks occur during general anaesthesia with an incidence of 1:1000 to 1:10. 000 – i.e. very rarely: Awareness (this refers to unintentional wakefulness during the anaesthesia). Many patients are most afraid of being conscious during the procedure and at the same time unable to communicate.

However, the anesthetists are very good at estimating and varying the depth of the anesthesia, so this fear is largely unjustified. The risk of awareness in children is about ten times higher than in adults. For both age groups, however, it was ten times higher in the 1970s than it is today.

Under certain circumstances, saliva or stomach acid can enter the lungs (so-called aspiration), which can lead to pneumonia or a lung abscess. For this very reason, anaesthetists prefer the patient to be fasting in the sense of an empty stomach before the induction of anaesthesia, i.e. not having eaten or drunk anything for about 6 hours before the procedure. This minimizes the risk of receding stomach contents.

Furthermore, states of prolonged confusion of the patient after the anaesthesia is discharged are also described with such frequency. If general anesthesia is induced in connection with an operation and the patient is transfused with foreign blood during this operation, more serious infections can also occur if the blood was contaminated with hepatitis viruses, for example. In difficult cases, the larynx, vocal cords, throat or windpipe may be injured during intubation, resulting in hoarseness or even shortness of breath.

If necessary, permanent vocal damage up to loss of voice can be the result. In very serious cases, permanent shortness of breath or severe allergic reactions may occur. If an artery instead of a vein is accidentally punctured to induce general anesthesia, this can lead to life-threatening overreactions of the cardiovascular system.

Very rare risks of general anaesthesia are those that occur with less than one in ten thousand anaesthesias. These include cardiovascular arrest, which requires immediate resuscitation, and respiratory arrest, to which the same applies. In addition, the formation of so-called thrombi (blood clots) can occur, which can block a blood vessel – in this case one speaks of a so-called embolism.

This can result in severe organ damage. The risk of sepsis (blood poisoning) also exists at this frequency, as does infection with life-threatening viruses such as the HI virus, which triggers the immunodeficiency disease AIDS, or other viruses if the patient is transfused with foreign blood during general anesthesia. Severe allergic reactions are also described with the same frequency, as are organ damage or a heart attack.

If an error occurs during venipuncture, for example if a nerve is irreversibly damaged, paralysis or permanent sensory disturbances may remain. If an artery is accidentally punctured instead of a vein (see above), this can result in considerable bleeding. In particularly unfavorable cases, the drugs that are supposed to induce anesthesia and insensitivity to pain can cause life-threatening metabolic disorders as a consequence, which often ends in so-called malignant hyperthermia. This is understood to be such an increase in body temperature that, in the worst case, the brain and kidneys in particular can suffer irreversible damage.