Causes | Complications in anesthesia


There are several reasons why complications under anesthesia occur during surgery. Probably the most common cause is an allergy or intolerance to the drugs or substances used. Some patients react allergic to local anesthesia, for example.

Particularly during visits to the dentist, patients notice that the injection that the dentist gives in order to drill a tooth without pain brings unexpected complications. However, it is also possible that the complications caused by the local anaesthetic only become apparent on the skin during the anaesthetic, for example when an injury needs to be sutured or when a patient has a mole removed under local anaesthetic. During such a local anaesthesia it can also lead to headaches, sensory disturbances or in rare cases to damage to the nerves.

However, it is also possible that the cause of the complication during anaesthesia is not at all due to the anaesthetic but to another medication. In many operations, especially dental operations, the patient is always given an additional antibiotic so that the germs that are everywhere in the body do not colonise the open wound. However, it is possible that the patient has an allergy to the antibiotic.

Penicillin allergy is particularly common in patients. In this case, the allergic reactions can lead to complications during anaesthesia, although the reaction is due to the antibiotic and not to the anaesthesia itself. There may also be an intolerance to other medications, which is not directly related to the anaesthesia but is related to it.

Especially after anaesthesia, complications such as nausea and vomiting can occur. Only in rare cases does the patient accidentally inhale the vomit. This can happen because the oesophagus and trachea are located directly behind each other in the neck.

If the patient vomits while lying down, it can happen that the vomit comes up through the oesophagus and then is not completely vomited but is partially inhaled through the trachea. This can lead to complications, especially after anaesthesia, which may make it necessary for the patient to have a stomach tube inserted or to be intubated. Inhalation of vomit is called aspiration, the subsequent pneumonia is called aspiration pneumonia.

It is very important that during the conversation with the anaesthetist the patient tells him all the medicines he is taking. If a patient is taking blood-thinning medication such as Marcumar or aspirin, he or she must inform the anaesthetist. Even if a patient has a known bleeding disorder in which the blood does not clot, it is essential to inform the anesthesiologist, otherwise there may be considerable complications during the anesthesia, as greater blood losses occur during the operation.

At the same time, it is also possible that so-called thromboses develop under anaesthesia. A thrombosis is a blockage of a blood vessel, which can then lead to a reduced blood flow at this point. It can also lead to an embolism.

In this case, the blood flow carries a small clot of blood into the lung, for example, and in the worst case leads to a fulminant pulmonary embolism. The worst complication of anaesthesia is death from cardiovascular failure or respiratory arrest. Malignant hyperthermia is particularly feared in this context.

This is an allergy to the anaesthetic drugs. Most patients with malignant hyperthermia are not aware that they suffer from this disease as it only occurs under anaesthesia and does not affect their daily life. The complications that occur during anesthesia include a rapid rise in temperature and heart rate, which can lead to damage or death.

This phenomenon is called malignant hyperthermia Especially in older, immobile patients with diabetes mellitus, complications can occur after anesthesia, which mainly affect the kidney. In this case, kidney failure can occur, either unilaterally or bilaterally, which can mean that patients have to go on dialysis afterwards. All the risks mentioned so far are so-called non-specific risks, with the exception of malignant hyperthermia.

They are called non-specific because the risks are not only due to the anesthesia, but, as with antibiotics, to a drug that is administered under anesthesia but is not directly related to it. However, there are also some specific complications which are directly related to the anaesthesia. In order to be able to perform anaesthesia, the doctor must inject the medication for anaesthesia into the vein of the patient.

Usually, the highly visible vein in the elbow is used for this purpose. Due to the sharp needle, it is of course possible that the doctor may accidentally injure a nerve, but this is extremely rare in the area of the elbow bend. It is also possible that germs are introduced into the vein by the puncture through the skin.

This can then lead to inflammation, in the worst case the inflammation can spread throughout the body. In this probably worst case of complications during anaesthesia, one speaks of a so-called sepsis or blood poisoning. A far more frequent complication during anaesthesia, however, is that the doctor accidentally punctures the vein, causing blood to leak from the vein.

This leads to a bruise (haematoma), which is usually in the area of the elbow bend, but rarely causes pain and can be considered harmless. If a patient has to be intubated during anaesthesia, i.e. ventilated via a tube, complications may occur during anaesthesia. After an intubation, sore throat, hoarseness and difficulty swallowing are also common.

These complications, which occur after anaesthesia, are unpleasant but no longer dangerous. Since local anaesthetics are usually applied locally in low concentrations, systemic effects and intoxications are rare. However, if a larger concentration enters the bloodstream, various symptoms of intoxication can occur, such as metallic taste in the mouth, numbness around the mouth, tinnitus, cramps, coma, etc.

The heart can also be affected and cardiac dysrhythmias can occur, even leading to circulatory failure. It is then necessary to secure the vital functions, e.g. by intubation and oxygenation, and prevent further damage. Blocking a nerve is a local anaesthetic procedure that is usually used for operations on the extremities, e.g. leg, foot, arm.

Since a local anaesthetic must be injected specifically into the area around the nerve to be blocked, accidental nerve blocks are rare. In addition, this procedure requires a deeper penetration into the tissue than, for example, surface anaesthesia. Should a nerve be accidentally blocked, however, this is not permanent.

Depending on the anesthetic used, the effect will subside after a certain time and the corresponding body part should function normally again. Local anaesthetics work by blocking the conduction of stimuli from one cell to the next, so the pain sensation is not transmitted. If too much of the drug accidentally gets into the bloodstream, side effects may occur. In the heart, impairment of the conduction leads to a drop in blood pressure and cardiac arrhythmia, which in some cases can be life-threatening. During therapy, the main focus must be on securing the vital functions and protecting the patient from life-threatening situations.