Today you will not surprise anyone with such a treatment method as surgical intervention. But a few centuries ago, the operation was equated with death: most patients died from pain shock or sepsis. For a long time, the introduction of a person into surgical sleep remained the most difficult task of medicine. With the study of chemistry, the process went faster. Better mixtures and preparations for anesthesia were created, which, in addition, are now carried out in different ways. One of them is endotracheal anesthesia. What it is? How is it used and in what cases is it needed? We will answer these and many other questions in the article.
From the history of endotracheal anesthesia
This type of anesthesia was first tried in the fourteenth and fifteenth centuries, when the doctor Paracelsus from Switzerland inserted a tube into the person’s trachea, which saved his life. Three centuries later, in this way they saved people from a lack of air. In 1942, an anesthetist from Canada for the first time used muscle relaxants - substances that reduce the tone of skeletal muscles up to complete immobilization. Thanks to this discovery, anesthesia has become safer and more perfect, allowing specialists to completely control the course of surgical sleep during surgery.
In the middle of the 20th century, endotracheal anesthesia began to develop rapidly, which was facilitated by Soviet doctors. Today, this is the most common method of general anesthesia used in most operations.
Endotracheal anesthesia: what is it?
In order to protect the body from great stress during surgery, anesthesia is used. It may be local, regional or general. The latter species is called anesthesia. It is characterized by a complete “shutdown” of the patient’s consciousness with the onset of surgical sleep. In modern anesthesiology, intravenous, mask or combined anesthesia is used. The latter combines two methods: substances enter both the bloodstream and the respiratory tract. This species is called endotracheal anesthesia.
Experts rightly consider it the safest and most effective method of pain relief: it allows you to fully control the patient’s condition, achieve deep surgical sleep and relaxation of skeletal muscles, as well as avoid unpleasant complications such as aspiration and respiratory failure.
Indications
Endotracheal anesthesia protects the patient from pain shock and respiratory failure, which allows it to be used during operations and resuscitation. Indications for combined anesthesia may include:
- surgery on the mediastinum, pharynx, inner ear, oral cavity and head;
- interventions in which it is necessary to use muscle relaxants;
- disruptions in the nervous system;
- full stomach syndrome;
- risk of airway obstruction.
Endotracheal general anesthesia is often used for long-term operations, which last more than 30 minutes. It can be used at any age in different conditions of the patient, because it does not burden the heart and is much less toxic to other methods of pain relief.
Contraindications
Routine surgical treatment (for example, surgery to remove a mediastinal tumor) is accompanied by a thorough study of the patient's condition. The doctor has the necessary time to familiarize himself with the patient’s medical record, managing to calculate the possible risks and identify contraindications to a particular anesthesia method. Combined anesthesia is not recommended in the following conditions:
- infectious diseases;
- pathology of the liver, kidneys;
- suspected myocardial infarction;
- pathology of the respiratory tract;
- physiological features of the structure of the pharynx;
- severe endocrine disorders.
Especially dangerous is the use of endotracheal anesthesia for infections of the upper respiratory tract, since there is a high risk of lung infection.
Stages of Combined Anesthesia
So, endotracheal anesthesia. What is this for a doctor? An anesthesiologist performs three consecutive stages of action: the introduction of surgical sleep, maintaining a stable state and awakening. The first stage is the implementation of mild induction anesthesia. The patient receives drugs intravenously or inhales a mixture of gases. When the muscles are completely relaxed, the anesthetist inserts an endotracheal tube into the lumen of the trachea. It provides ventilation of the lungs with oxygen and inhalation with gaseous anesthetics.
After the surgeons have completed their work, a crucial moment for the anesthesiologist comes - the withdrawal of the patient from anesthesia. The dosage of drugs is gradually reduced. After the restoration of independent breathing, extubation is performed - removal of the endotracheal tube from the trachea. The patient is transported to the intensive care unit, observing the vital signs and the process of postoperative recovery.
Introductory anesthesia
Mild initial anesthesia is necessary for painless and safe intubation, without which endotracheal anesthesia is impossible. To achieve this state, inhalations or intravenous pain medications are used. In the first case, the patient breathes through the mask in pairs of Etrana, Farana, Fluorotana or other similar mixtures of anesthetics. Sometimes nitrous oxide with oxygen is enough.
As intravenous drugs, barbiturates and antipsychotics (droperidol, fentanyl) are usually used. They are used in the form of a solution (not more than 1%). The dose of the drug is selected by the anesthetist individually for each patient.
After mild anesthesia has worked, tracheal intubation is performed. For this, muscle relaxants are used to relax the muscles of the neck. The tube is inserted using a laryngoscope, after which the patient is transferred to mechanical ventilation. The stage of deep anesthesia begins.
Droperidol: instruction
Droperidol is an antipsychotic often used in endotracheal anesthesia. By chemical structure, this substance is a tertiary amine. It has a sedative effect after 3 minutes after administration. It blocks dopamine receptors, which causes neurovegetative inhibition. In addition, it has an antiemetic and hypothermic effect. It affects breathing slightly.
It is prescribed for premedication, induction of anesthesia, myocardial infarction, shock, severe angina pectoris, pulmonary edema and hypertensive crisis. It is recommended as a drug that eliminates nausea and vomiting. It has low toxicity, which allows its use in pediatric surgery and obstetrics.
The use of antipsychotics for induction of anesthesia
There are several options for the implementation of antipsychotics. Induction anesthesia is usually carried out according to the following scheme: droperidol, the instruction of which was discussed above, in the amount of 2-5 ml with 6-14 ml of fentanyl is administered intravenously to the patient. At the same time, a mask with a mixture of nitrous oxide and oxygen in a ratio of 2: 1 or 3: 1 is served. After oppression of consciousness, muscle relaxants are introduced and begin intubation.
Droperidol has a neuroleptic effect for 4-5 hours, so it is administered at the beginning of anesthesia. Calculate it taking into account body weight: 0.25-0.5 mg / kg. Repeated administration of the drug is necessary only with prolonged operations.
Fentanyl in the amount of 0.1 mg is administered every 20 minutes and its supply is stopped 30-40 minutes before the end of the surgery. The initial dose is 5-7 mcg / kg.
Intubation
After oppression of consciousness, artificial lung ventilation with oxygen is performed using an anesthetic mask. After which the doctor performs intubation through the mouth (less often through the nose). They throw their heads back, open their mouths. A laryngoscope is inserted with a straight blade along the midline between the sky and tongue, pressing the latter up. Moving the instrument further, raise the top of the epiglottis. A glottis is shown into which the endotracheal tube is inserted. It should go into the trachea by about 2-3 cm. After successful intubation, the tube is fixed and the patient is connected to the ventilator.
Less commonly used is a laryngoscope with a curved blade. It is introduced between the base of the epiglottis and the root of the tongue, crushing the latter upward from itself. If it is not possible to insert the tube through the mouth, the lower nasal passage is used. So, for example, an operation is performed to remove an oral cyst.
Maintenance and recovery from anesthesia
After intubation and connecting the patient to the ventilator , the main period begins. Surgeons are actively working, the anesthesiologist closely monitors life support indicators. Every 15 minutes, heart rate and blood pressure are checked, and the patient’s cardiac activity is monitored.
General anesthesia is maintained with additional doses of antipsychotics, muscle relaxants or inhalations with mixtures of anesthetics. The operation under combined anesthesia allows the anesthetist to adjust to the body's needs for pain relief, providing an optimal level of safety.
After the end of surgical procedures, the last stage sets in - the way out of narcotic sleep. Until this moment, the dosage of the drugs is gradually reduced. Atropine and proserin are administered at intervals of 5 minutes to restore breathing. After making sure that the patient is able to breathe independently, extubation is performed. To do this, clean the area of ​​the tracheobronchial tree. After removal of the tube, a similar procedure is performed with the oral cavity.
Postoperative observation
After leaving the operating room, the patient is placed in the intensive care unit, where his condition is carefully monitored. After general anesthesia, discomfort develops, less often complications. Usually postoperative patients complain of:
- pain
- discomfort in the throat;
- nausea
- weakness and muscle fatigue;
- drowsiness;
- confusion of consciousness;
- chills;
- thirst and lack of appetite.
These symptoms usually disappear within the first 2-48 hours after surgery. To eliminate pain, analgesics are prescribed.
So let's summarize. Endotracheal anesthesia - what is it? This is a method of introducing a person into surgical sleep, allowing you to perform complex operations, controlling the activity of the respiratory system. Combined anesthesia is less toxic, and the depth of anesthesia is easy to control throughout the entire period of intervention. Endotracheal anesthesia primarily means intubation, followed by connecting the patient to a ventilator. In this case, both inhaled and drug anesthetics are used, which are usually combined.