Side effects
Like almost every medical procedure, general anesthesia is not free of side effects. Although one has a lot of experience with the procedure and it is well tolerated in the majority of cases, one should point out the most important side effects. The form and extent to which side effects occur after general anesthesia depends on many factors.
Older people or those with pre-existing conditions are particularly susceptible to them, but overall, various risk factors can have an influence. In general, after general anaesthesia, side effects such as brief confusion and drowsiness occur immediately after waking up. It is initially difficult to orientate oneself.
However, these side effects are normal and do not last long. A very frequently observed side effect is PONV. This abbreviation stands for “postoperative nausea and vomiting“, which means “postoperative nausea and vomiting”.
This extremely unpleasant, but usually harmless side effect is described in 20-30% of patients after general anesthesia and is not of long duration. Some risk factors favour the occurrence of PONV. Children and adolescents, women and people suffering from motion sickness are more likely to experience nausea and vomiting after general anesthesia.
With potent medications such as dexamethasone, antihistamines and setrons, which are used to treat nausea, the symptoms can usually be well controlled. In addition, medication is often given prophylactically before general anesthesia to prevent the occurrence of PONV. The mechanism of its development is not yet well understood.
It is certain that certain anaesthetics and drugs used during anaesthesia can irritate certain receptors in the brain, which trigger the body’s own protective reflex against toxic substances. A second side effect often seen after an operation under general anesthesia is hypothermia with postoperative tremor (shivering). As the name suggests, the patient has an excessively increased sensation of cold.
One cause could be temporary hypothermia during general anesthesia. As a reaction to this, the body tries to produce heat with the muscle tremor and to counteract the hypothermia. However, other causes are also discussed, so that the process behind this is not really understood.
The frequency is given as 5-60%. As a treatment for these side effects, there are on the one hand calming agents available, and on the other hand the body can be supported with warming blankets and warmed infusions to help it produce heat. Since general anesthesia involves deep medications that intervene deeply in the consciousness and the complex structure of the brain, various types of cognitive side effects can occur after general anesthesia.
These side effects mainly affect older people. First of all, post-operative delirium, which is divided into a hyperactive and hypoactive form, depending on the increased or decreased excitement and activity. After general anesthesia, consciousness and cognitive attention are restricted.
Thus, memory disorders may occur and the patient’s temporal and spatial orientation may be impaired. Other side effects described are sleep disorders and general restlessness. Sometimes mild hallucinations or delusions may occur.
The frequency of delirium is reported to be 5-15% and sometimes considerably different. If side effects such as lack of concentration only appear after days or months, one speaks of cognitive dysfunction, which can last for a long time and in the worst case be permanent. In addition to these side effects, which are limited to the central nervous system, there are also a number of side effects during general anesthesia, which can occur organ-specifically due to the methods and instruments used.
Since artificial respiration is used during general anesthesia, post-operative pain and irritation of the oral cavity, neck and vocal cords may be caused mechanically by an inserted tube. Swallowing difficulties after general anesthesia may also occur. In rare cases, the teeth are damaged during intubation, i.e. when the breathing tube is inserted into the trachea.
Because of the patient’s position during the operation, damage to nerves with resulting numbness or loss of sensation is conceivable. Since general anesthesia also involves multiple accesses to the veins or arteries, bruising is possible at the injection sites.The described side effects are possible, but none of them need to occur. Overall, thanks to modern anaesthetics and well-researched concomitant medication, general anaesthesia is now a well-tolerated procedure with few side effects. However, if any should occur, these can usually be brought under control.
