Complications in anesthesia


As with any medical procedure, various complications can arise during anesthesia, i.e. numbing the body for an operation.

The risk of complications occurring during anesthesia is usually very low, but the patient should be aware of this.
Before each operation, a patient must be informed by his anesthetist, i.e. the doctor who initiates the anesthesia and who remains with the patient to monitor it during the operation.

This means that on the one hand the patient receives an information sheet in which possible complications during the anesthesia are described, on the other hand the anesthetist speaks with the patient before the operation so that the patient can ask questions and communicate possible fears to the doctor.

Frequency distribution

There are serious complications during anesthesia very rare and come especially at elderly patients who only moved a little before the operation or who suffer from several diseases.
In total, around 0.4 out of 100,000 previously healthy patients with no previous illnesses during anesthesia.

This shows that the Very low risk is and mostly through constant monitoring and the development of new and better narcotics continues to decline.

Slight complications however, under anesthesia are more common. Every fifth patient complains of nausea after the operation and bruises at the injection site are not uncommon.
It should be said, however, that without the operation many patients would definitely die. Therefore, it is always the benefit versus the risk that counts to weigh up and if in doubt, take a day of nausea.

Most common complications

With anesthesia it can complications during and after surgery come. This is very rare. However, the patient must be informed about the possible risks before each procedure. Complications can occur with general anesthesia as well as with spinal cord anesthesia or local anesthesia.

The most common complication General anesthesia is the nausea that may occur due to the medication after the operation. For very severe nausea and Vomiting after anesthesia Medicines against nausea can be administered both after the operation and as a preventative measure during anesthesia.

It also often happens that the patient very much after the operation very cold and shivering. The tube, which is inserted into the windpipe for ventilation, can cause hoarseness and sore throat after the operation. In rare cases, teeth or gums are damaged during intubation. The tube can cause the patient to vomit during the operation and this can get into the airways. This can lead to serious complications as the Lung tissue is very sensitive to stomach acid. This is why patients need to be fasted prior to surgery.

At the points where the anesthetist provides access, i.e. mostly in the Elbow, it can too Secondary bleeding or bruises or nerves can be injured.

Elderly patients in particular may experience confusion after the operation Delusions and disorientation come. Therefore, especially in the case of older people, care is taken to ensure that the dose of the anesthetic is very low or that local anesthesia is performed.

Complications can also arise during the operation. Which includes allergic reactionthat are triggered primarily in response to certain medications. Latex, which is contained in various surgical materials, can also trigger allergic reactions. These are expressed in Reddened skin, shortness of breath or circulatory failure. In addition, at genetic predisposition the so-called malignant hyperthermia occur. Although this is extremely rare, it is considered life-threatening for the patient. After the muscle relaxant is administered to relax the muscles in the introductory phase of the anesthesia, it occurs in the patient Muscle stiffness, an increase in body temperature, a racing heart and, as a result, metabolic and organ failure. However, the patient can be treated by giving certain medications in good time.

It can become too during an operation Disorders of the cardiovascular system because the body's own regulatory mechanisms have been switched off by the anesthesia. This can lead to drastic changes in blood pressure or even cardiac arrhythmias up to and including cardiac arrest. However, these are exceptional cases that may preferentially occur in people with existing heart disease. The anesthetist monitors the patient very closely during each anesthesia so that any changes in the heart rate can be detected immediately.

It can also intraoperative wakefulness come.This happens extremely rarely and is mostly due to an insufficient effect of the anesthetic drug due to drug abuse.


There are several reasons why complications under anesthesia can occur during the operation. Probably the most common cause is one allergy or an intolerance to the drugs or substances used.

For example, some patients respond to a Local anesthesia allergic.
Especially during Visits to the dentist the patient then notices that the syringe that the dentist gives to drill a tooth without pain brings unexpected complications.

However, it can also be the case that the complications that arise from local anesthesia are only noticeable on the skin during the anesthesia, for example when an injury has to be sutured or when a patient is under local anesthesia Mole gets removed.

During such a local anesthetic it can also be too A headache, Sensory disturbances or, in rare cases, damage to the nerves.
However, it may also be that the cause of the complication during anesthesia is not the anesthetic agent at all, but one other drug.

In many operations, especially dental operations, the patient is always given an additional antibiotic given so that the germs, which are everywhere in the body, do not colonize the open wound.

However, the patient may have an allergy to the antibiotic.
One can find one particularly often Penicillin allergy in patients. In this case, complications during anesthesia may arise due to the allergic reactions, although the reaction is due to the antibiotic and not the anesthesia itself.

There may also be an intolerance to other drugs, which is not directly attributable to the anesthesia but is related to it.
Especially after the anesthesia there can be complications like nausea and Vomit come.

Only in rare cases does the patient accidentally inhale the vomit. This can happen because the esophagus (Esophagus) and the windpipe (Trachea) lie one behind the other in the neck.

If the patient vomits while lying down, it can happen that the vomit comes up through the esophagus and is then not completely vomited but is partly inhaled through the windpipe.
This can lead to complications, especially after anesthesia, which may make it necessary for the patient to have a Nasogastric tube gets applied or is intubated.

Inhalation of vomit is called aspiration referred to, the following lung infection as Aspiration pneumonia.
It is very important that while talking to the anesthetist, the patient should state all the medications he is taking.

Takes a patient blood-thinning drugs like for example Marcumar or aspirinhe has to inform the anesthetist.
Even if a patient is a familiar one Bleeding disorder has in which the blood does not clot, this must be reported because otherwise there may be considerable complications during the anesthesia, as major blood losses occur during the operation.

At the same time, however, it can also be that under anesthesia so-called Thrombosis arise.
Thrombosis is a blockage of a blood vessel, which can then lead to the fact that the blood flow at this point only deteriorates. An embolism can also occur. In this case, with the help of the blood flow, a small clotted blood clot is carried into the lungs, for example, and in the worst case leads to a fulminant Pulmonary embolism.

The worst complication of anesthesia is death Cardiovascular failure or through Apnea.
What is particularly feared in this context is the malignant hyperthermia.

This is an allergy to the anesthetic drugs.
Most patients with malignant hyperthermia are not known to have suffered from the disease as it occurs only under anesthesia and does not affect daily life.

The complications that occur during anesthesia are, among other things, extremely quick Increase in temperature and heart rate, which in turn can lead to damage or death.
This phenomenon is called malignant hyperthermia

Especially in older, immobile patients with the Diabetes (Diabetes mellitus) there may be complications after the anesthesia that mainly affect the kidneys.
In this case it can become a Kidney failure, come either unilaterally or bilaterally, which can result in patients subsequently following the dialysis have to.

All of the risks mentioned so far are so-called unspecific risksexcept for malignant hyperthermia. They are referred to as unspecific because you have the risks not just on anesthesia lead back can, but as for example with antibiotic to a drug that is given under anesthesia but is not directly related to it.

However, there are also a few specific complicationswhich are directly attributable to the anesthesia.
To be able to perform anesthesia, the doctor has to inject the anesthetic drug into the patient's vein.

Usually the clearly visible vein in the elbow is used for this. Due to the sharp needle, the doctor can inadvertently injure a nerve, but this in the area of ​​the elbow very rarely is.

It is also possible that germs are introduced into the vein through the puncture through the skin.
This can then lead to inflammation, in the worst case the inflammation can spread throughout the body. In what is probably the worst case of complications during anesthesia, one speaks of a so-called sepsis or blood poisoning.

A far more common complication during anesthesia, however, is when the doctor accidentally punctures the vein to close it Blood leak comes from the vein.
This leads to a bruise (hematoma), which is usually in the area of ​​the elbow, but rarely causes pain and as harmless is to be assessed.

If a patient has to be intubated during anesthesia, i.e. ventilated through a tube, this can result in complications during anesthesia.

It is also common after intubation Sore throat, hoarseness and difficulties swallowing.
These complications, which occur after anesthesia, are uncomfortable but no longer dangerous.

Local anesthetic intoxication

Since local anesthetics are usually applied locally in low concentrations, systemic effects and intoxication are rare. However, if a higher 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 arrhythmias up to and including circulatory failure can occur. The vital functions then apply, e.g. through intubation and oxygen supply, to secure and prevent further damage.

You may also be interested in this article: Side effects of local anesthesia

Accidental nerve block as intoxication

Blocking a nerve is a local anesthetic procedure that is usually used during surgery on the extremities, e.g. Leg, foot, arm, is used. Since a local anesthetic has to be injected into the area around the nerve that is to be blocked, accidental nerve blocks are rare. In addition, for this procedure one has to penetrate deeper into the tissue than e.g. with surface anesthesia. However, if a nerve is accidentally blocked, this is not permanent. The effect subsides after a certain time, depending on the anesthetic used, and the corresponding part of the body should function normally again.

Cardiac arrhythmias as a complication

Local anesthetics work by blocking the conduction of stimuli from one cell to the next, so that the sensation of pain is not passed on. If excessive amounts of the drug accidentally get into the bloodstream, side effects can occur. In the heart, impaired conduction leads to a drop in blood pressure and cardiac arrhythmias, which in some cases can be life-threatening. During therapy, particular attention must be paid to safeguarding the vital functions and protecting the patient from life-threatening situations.


Complications that can usually occur during anesthesia well diagnosed become.

The patient is under anesthesia supervised by an anesthetisttrying to avoid any complications fix directly. For example, if there is a drop in blood pressure, this is registered directly and the anesthetist can give specific medication to avoid the drop in blood pressure.

If the anesthetist notices during the operation that the patient is suffering from malignant hyperthermia, he intervenes directly and inputs Antidote, which is available in every operating theater in Germany and thus protects the patient from death.
The heart is also continuously monitored by EKG, and the lung values ​​are checked in order to ventilate or intubate the patient if the oxygen drops.


If complications arise during anesthesia, this can get through different symptoms express.

It can become one Drop in blood pressure but also to one Increase in blood pressure come. The heartbeat (heart rate) may increase or decrease. The patient may suddenly breathe lesswhat then to one Waste of oxygen leads in the blood.

So there are various symptoms that indicate complications during anesthesia. Complications that occur after anesthesia are usually characterized by symptoms such as malaise or vomiting.
In addition, the patient should pay attention to whether his breathing is normal or whether he has problems.


If complications occur during anesthesia, these can usually be easily fixed by the anesthetist become.
For this purpose, the anesthetist sits next to the patient during the entire operation and monitors his values ​​so that he, should complications arise, intervene directly and fix the cause of the complications.
Therefore, medication is always available during the entire operation, which can be given in the event of malignant hyperthermia or other unexpected complications.

In addition, there are oxygen masks and intubation tubes in every operating room, which are used in the event of a complication to help the patient.

The patient can counter the usual complications after the operation such as nausea or vomiting on demand also Medication get which the Alleviate nausea and thus compensate for the complications caused by the anesthesia.

If local allergic reactions occur, the patient can also receive an antihistamine. This is a drug that the allergic reaction of the body reduced and thus the complications caused by the anesthesia subside again.


Generally it occurs during anesthesia rarely to complications and thus the forecast also very good.

Nevertheless, especially in older patients, one should always weigh the benefits of the operation against the risks.
All anesthesia carries a certain risk and it is therefore important to be aware of the possible complications before undergoing an operation. At the same time, however, it is also important to realize that anesthesia is only very rare leads to such serious complications that it leads to death or lifelong restrictions as medicine continues to make progress and it does meanwhile very well tolerated There are narcotics that have a very low risk of complications.


Around possible complications during anesthesia to avoid It is very important that the patient informs the doctor of all their concerns during the preparatory or educational discussion.

In addition, the patient should be aware of all his medication and his previous illnesses or previous operations Inform doctor.

Allergies should also be mentioned and also whether there have been cases of malignant hyperthermia in the family.
The doctor asks all these questions and the patient just has to remember to answer them all correctly and if the patient is unsure about, for example, what medication he is taking, he should tell the doctor, because he can then ask the family doctor about the current medication.