Definition Anaesthesia
Anaesthesia is an artificially induced state of unconsciousness. Anaesthesia is induced by administering medication and is used to carry out therapeutic and/or diagnostic measures without causing pain.
Procedure of an anesthesia
The procedure of an anesthesia is divided into three stages: The preparation for an anesthesia (so-called general anesthesia) includes in a broader sense also the explanatory talk, which the anesthesiologist conducts with the patient before the anesthesia. This is intended to uncover possible risks for the anaesthesia. These can be, for example, pre-existing heart or lung diseases.
Various blood values, such as the coagulation of the blood and the ability of the blood to transport oxygen (suction haemoglobin value) are also checked before anaesthesia. It is important that the patient informs the anesthesiologist about existing allergies. Of particular importance are: allergic reactions to certain drugs (e.g. penicillin), allergy to soy products and allergy to plasters.
If the patient experiences a reflux of stomach contents, e.g. at night, he should also mention this.
- Preparation of the patient for anesthesia
- Performance of the anaesthesia
- Wake up from anesthesia and follow-up.
In order to ensure a relaxed and sufficient sleep the night before the operation/anaesthetic, a sleeping pill can be prescribed. This is usually a benzodiazepine such as Tavor (lorazepam).
Another drug can be taken immediately (but at least half an hour) before the operation to calm the patient down. This is also a benzodiazepine, usually Dormicum (midazolam). Although a strict ban on eating, drinking and smoking is generally to be observed before the operation, the tablets may be taken with a few sips of water.
If there is excessive anxiety before the operation, homeopathic remedies may be taken in the run-up to the operation to relieve anxiety or to positively influence the risk of thrombosis, among other things. Anesthesia must be planned individually. For this purpose there is usually a preliminary discussion with the anesthetist and the patient on the day before the operation.
It is clarified whether certain allergies or previous illnesses exist and the patient is informed about the risks. Then the actual planning of the operation begins. The anesthetist decides on the medication and the ventilation safety device.
Shortly before the anaesthetic is administered, a safety consultation takes place, where important information is again asked for and it is ensured that it is the right patient and the right surgery. Only after these discussions does the introduction begin. Preparation for the anaesthesia is usually carried out by a nurse (often with specialist training in anaesthesia and intensive care medicine).
The aim of the preparation for anterior anaesthesia is above all the constant monitoring of vital signs: the ECG continuously derives the heart‘s actions, a blood pressure cuff on the upper arm measures the blood pressure, a clip on the finger gives continuous feedback on the oxygen content in the blood. In order to inject drugs and fluids directly into the bloodstream, a vein must first be punctured to create a permanent venous access. This is often done on both forearms.
The anaesthetic induction describes the preparation for anaesthesia and the securing of respiratory and circulatory functions. During operations, this induction takes place in the room in front of the operating room and is carried out by the anaesthetist or anaesthesia nurse. In an emergency, however, this can also be done on the street by the rescue service, but this involves greater risks.
First of all, the patient is given venous access so that medication can be administered and the monitoring monitors are connected. Gradually, the anaesthetist will then administer the anaesthetic medication. The patient falls into a twilight state and falls asleep.
As soon as the patient stops breathing, the anesthesiologist takes over and secures the airways with a breathing tube in the trachea. Ventilation can now be continued through the ventilator. When the preparation is complete, the patient is pushed into the operating room and further prepared for surgery.
The anaesthetic induction begins with the administration of pure oxygen, which the patient inhales for a few minutes through a mask.Since the patient’s lungs are not filled with oxygen for a short time after falling asleep due to the anesthetic, this administration of pure oxygen serves as a buffer. This is called preoxygenation. First, a strong painkiller is injected via the intravenous cannula during anesthesia.
This is an opioid, often fentanyl or sufentanyl. The effect initially manifests itself by a certain dizziness and drowsiness, which is generally perceived as pleasant. The anesthetist then injects the actual anesthetic agent (so-called hypnotic) – the most common anesthetic is Propofol.
Sleep then occurs in less than a minute. Breathing is now taken over by the anaesthetist or the nursing staff: For this purpose, air is pumped into the lungs via a pressure bag and a mouth and nose mask. If this form of ventilation does not present any difficulties, a so-called muscle relaxant is injected.
This makes the subsequent intubation easier and in many cases also facilitates the operation, provided that the muscles are less tense. In order to be able to ensure mechanical ventilation during the operation under anesthesia, there are generally two ways of pumping air into the lungs. One is a so-called laryngeal mask, which closes the entrance to the trachea with an inflatable rubber ring.
The second is a plastic tube, which is inserted into the trachea by means of intubation. While the laryngeal mask is more gentle on the mouth and throat, ventilation via a tube offers better protection against the overflow of stomach contents into the lungs. and intubation anesthesiaAfter successful placement of the laryngeal mask or intubation, it is important to maintain a state of sleep (anesthesia) during the operation.
For this purpose, either continuous anaesthetic is applied via the intravenous cannula (also usually propofol) or continuous anaesthetic is given into the lungs via the air we breathe. In the first case, this is referred to as TIVA (total intravenous anesthesia), in the second case as inhalation anesthesia. Commonly used inhalation anaesthetics are desflurane, sevoflurane and isoflurane.
Painlessness is ensured by repeated or continuous administration of the opioid through the intravenous cannula. During the entire anaesthesia, the anaesthetist monitors the patient’s vital functions: How deep the anesthesia is can be determined by controlling the brain waves. In this process, electrodes on the forehead and temple are used to derive the brain waves and thus the depth of sleep (so-called BIS monitoring).
While the anesthesia is being discharged, the patient begins to breathe independently again. At this moment the tube or laryngeal mask is pulled out. In the hours after the anaesthesia or operation, blood pressure, blood oxygen level and heart action are monitored.
In the hospital this is done in the so-called recovery room.
- Breathing
- Blood pressure and
- Heart function.
The anaesthetic delivery is also the beginning of the wake-up phase. With most medications, waiting and stopping further administration is sufficient to reverse the effect.
The anaesthetist usually plans this while observing the operation, so that the drainage only takes a short time. Some drugs can also be specifically switched off by an antidote. This is possible with opioids and certain muscle relaxants.
When the effect of the anaesthetics wears off, the body gradually begins to control its own functions and begins to breathe on its own. The anaesthetist observes this and addresses the patient. As soon as the patient’s own breathing is sufficient, the breathing tube is pulled out, which often happens in the operating room.
If breathing is not sufficient, in rare cases a new breathing tube must be inserted. The patient is then taken to the recovery room, where a further check of the bodily functions is performed. The anaesthesiologist will accompany the patient throughout the anaesthesia, so that intervention in case of complications is possible.
In some patients, the drainage takes considerably longer, as the degradation of the drugs does not work equally fast for all people. The recovery time begins with the drainage of the anesthesia and thus with the lowering of the drug concentration in the blood. Independent breathing sets in and the eyes can be opened on demand.
As soon as the breathing tube is removed, the patient is taken to the recovery room and continues to be closely monitored.Already in the operating room, awareness is awakened a little, but the wake-up time takes a few hours altogether. In the wake-up room, it is possible to react directly to after-effects such as nausea and vomiting, and even more serious complications can be easily detected. Confusion often occurs after general anesthesia, which is also used to define the wake-up time.
This time ends when the patient is fully oriented. This means that the patient must know his own name, be able to estimate the date and know where he is. Only when the person concerned can answer these questions with certainty is he or she transferred to a normal ward.
An exception are major operations with subsequent artificial coma. These patients are often transferred directly to the intensive care unit and are only taken out of anaesthesia once their state of health has stabilized. General anesthesia is always a great strain on the body and is associated with some after-effects.
The anaesthetic drugs act centrally and thus on the brain. A frequent consequence of anaesthesia is therefore a slight confusion after waking up. In most cases, this recedes after a few hours.
However, in some patients, especially elderly people, a long-term delirium can develop, which in extreme cases can lead to a permanent need for care. Headaches are also a relatively common after-effect of anesthesia. In addition, ventilation can cause sore throat and hoarseness, as the breathing tube irritates the mucous membrane and the vocal chords. Some patients also complain of hair loss and sleep disorders, which can also be attributed to the strong medication. Most of the after-effects are rapidly diminishing without further intervention.
