Procedure of general anesthesia | General Anesthesia

Procedure of general anesthesia

In order to be able to carry out a surgical procedure undisturbed, the patient’s consciousness must be switched off during this time, the pain sensations must be reduced and thirdly, the muscles must be relaxed in order to be able to carry out appropriate surgical procedures. At the beginning of a general anaesthesia there is the patient education. It includes the duration of the general anesthesia and the reason as well as a detailed description of the procedure and the risks and side effects of general anesthesia.

In general, general anesthesia education takes place the day before the surgical procedure. The patient must sign and acknowledge that he/she agrees with the anesthesia and that he/she has been informed about the procedure. With general anesthesia, the patient must be fasting.

In concrete terms, this means that the last fixed meal should have been six hours ago and that two hours before the anesthesia no more should be drunk. In infants, there should be four hours between breastfeeding and the induction of anaesthesia. Non-compliance with these rules increases the risk of anaesthesia, as the patient may vomit and this vomit may be inhaled.

In case of emergency, this rule is not observed, as the operation is more important than protection against possible complications. On the day of the surgery the patient must be fasting. He will then be taken to the operating room and then to the induction room.He is given a large-lumen venous access through which appropriate infusions are administered.

Furthermore, he is monitored and his pulse, blood pressure, heart rate and oxygen saturation are permanently observed and recorded. The patient, who is still awake, has a mask held in front of his nose through which he has to breathe in oxygen. This saturates the blood with oxygen.

Afterwards, the patient is injected with a drug that cancels the waking state and lets him fall asleep. This is followed by the administration of the muscle-relaxing medication. As a result, the breathing muscles no longer function and the patient loses the ability to breathe independently.

Since the blood was previously saturated with oxygen, a short pause in breathing is no longer a problem. For the procedure, the patient is intubated and a tube is inserted into the trachea. This tube is attached to a ventilator and supplies the now deeply sleeping patient with sufficient oxygen.

The patient can also be ventilated through a ventilation mask which is inserted into the throat. Alternatively, the anaesthetist can also ensure continuous manual ventilation with a mask and a ventilation bag during short anaesthesia sessions. To maintain the general anesthesia, the patient today usually receives the drug Propfol.

Via the venous access and a so-called perfusor, a certain amount of medication per hour can be injected into the patient at regular intervals, automatically controlled. This prevents the patient from waking up. Although the patient has now lost consciousness and is no longer breathing independently, he still feels pain.

In order to be able to start the procedure, he is now given a painkiller in the vein, also at regular intervals. With this triple combination of drugs, the patient is sufficiently anaesthetized and the procedure can begin. This method of general anesthesia, in which all medications are administered through the vein, is also known as total intravenous anesthesia.

There is still the possibility of maintaining the sedative effect on the patient with a gas mixture. The gas formerly known as nitrous oxide is no longer used today due to its poor controllability. Today there are a number of other gas mixtures, e.g. halothane, which is used to maintain the anaesthesia.

In this anaesthetic procedure, the gas mixture is then permanently applied to the patient via the respiratory tract during the procedure. The anaesthetist is located next to the patient during the entire operation and monitors the vital organ systems. He or she will consult with the surgeon and is informed about the approximate end of the operation.

Shortly before the end of the operation, the amount of anesthesia the patient receives is reduced. It usually still takes some time before the anesthetic is washed out of the body. Until then, the patient sleeps and must be ventilated.

As a rule, the last stitches of the operation can still be performed, even if the anesthetic has already been discontinued. The administration of painkillers is usually continued. The next step is to reduce the muscle-relaxing medication.

As the patient regains the ability to breathe on his own, he usually starts breathing against the tube still in the lungs. The anesthesiologist closely monitors the oxygen saturation of the blood at this time of general anesthesia. If the saturation is not yet sufficient, the patient continues breathing for a while.

As breathing activity is regained, the patient tolerates the tube less and less. If this stage occurs, the tube is pulled. Additional mask ventilation can help to compensate for any oxygen debt at this stage.

The patient is then pushed out of the operating room and is taken to a recovery room where he is monitored for some time. If he is stable from his general functions, he is taken to the ward. The general anesthesia is now over.

The recovery time is defined as the period from the time the anesthesia is withdrawn until the patient is completely back to normal and usually takes one to three hours. The time until the patient is fully awake is mainly influenced by the size and type of operation, the choice of anaesthetic and individual previous illnesses. Damage to the liver or kidney, for example, leads to a delayed breakdown of the narcotic substances, which results in a longer recovery time. During the recovery period, the patient is usually in a recovery room, which is often connected to the operating area. This is important, because the circulation and breathing must be monitored until complete awakening.Only after the end of the recovery period is the patient transferred back to the normal ward or the intensive care unit, depending on the situation.