Tracheal extubation

Anesthesiologists often use concepts such as intubation and extubation. The first term - intubation - actually means the introduction of a special tube inside the trachea, which is necessary to ensure the patient's airway patency. Extubation is the opposite of intubation: the tube is removed from the trachea when it is no longer needed.

Extubation can be performed in a hospital setting or in an ambulance (outside the health care facility). [1]

Indications for the procedure

In cases where there is no need to monitor the respiratory tract, the endotracheal tube, installed during intubation, is removed. This is usually done when a subjective and objective improvement in respiratory function is achieved. For a more comfortable and safe manipulation, the doctor must make sure that the patient can breathe on his own, that his respiratory tract is passable, and the tidal volume will be sufficient. In general, extubation is possible if the respiratory center is adequately able to initiate inspirations at normal frequency, depth, and rhythm. Additional conditions for the procedure are normal strength of the respiratory muscles, "working" cough reflex, high-quality nutritional status, adequate clearance of sedatives and muscle relaxants. [2]

In addition to the normalization of the patient's condition and respiratory function, there are other indications. Extubation is performed with a sudden blockage of the endotracheal tube by foreign agents - for example, mucous and sputum secretions, foreign objects. After removal, reintubation or tracheostomy is performed, at the discretion of the doctor.

Another indication for extubation can be considered a situation where the further presence of a tube in the trachea becomes impractical - for example, when it comes to the death of a patient. [3]

Preparation

Preparing for extubation begins with careful planning of the procedure, namely with an assessment of the airway and general risk factors.

The state of the respiratory system is assessed according to the following criteria:

• no difficulty in breathing;
• no damage to the respiratory tract (edema, trauma, bleeding);
• no risk of aspiration and obstruction.

General factors are assessed according to such cardiovascular, respiratory, neurological, metabolic indicators, taking into account the characteristics of the surgical intervention and the patient's condition before extubation. [4]

In general, preparation consists in optimizing the general condition of the patient and other factors:

• check the quality of hemodynamics, respiration, measure temperature, assess metabolism and neurological status;
• prepare the necessary equipment and tools;
• monitor all vital body functions.

Optimally, the extubation manipulation is performed on an empty stomach. Most often, the patient is fully conscious. [5]

Technique extubation

Extubation is the removal of the endotracheal tube when the patient has all the prerequisites for spontaneous breathing. The manipulation is carried out in the following sequence of actions:

• if a gastric tube is present, aspirate the entire contents of the stomach;
• thoroughly sanitize the nasal and oral cavity, pharynx, tracheobronchial tree;
• the cuff is deflated and the endotracheal tube is removed gradually, slowly, preferably on inspiration.

During extubation, the tube is ejected in one clear but smooth movement. After that, a face mask is applied with the supply of one hundred percent oxygen, until the condition is normalized. [6]

Sometimes extubation is performed unplanned - for example, in patients with acute reactive psychosis, with poor patient fixation, or in conditions of insufficient sedation.

Emergency extubation in the following cases:

• with low or zero airway pressure;
• when the patient gives a voice;
• when the endotracheal tube comes out a few centimeters (depending on the age and the initial depth of the device).

The following are considered unreliable signs of the need for extubation:

• small tube exit (up to 20 mm);
• expressed anxiety of the patient;
• paroxysmal cough, sudden cyanosis (cardiovascular indicators need to be checked).

If extubation occurs unplanned, follow these phased actions:

1. With clear signs of the need for extubation, the cuff is deflated and the endotracheal tube is removed. If necessary, the upper respiratory tract is sanitized, after which artificial ventilation of the lungs is started using an Ambu bag (it is optimal to connect it to an oxygen source), or by mouth-to-mouth method. After normalization of indicators, the need for reintubation is assessed.
2. If unreliable signs are found, an attempt is made to use the Ambu bag. Positive manifestations: the chest and abdomen change the volume in time with the respiratory movements, the skin turns pink, when listening to the lungs, breathing noises are noted. If such signs are present, the endotracheal tube is brought to the required depth. In the absence of positive manifestations, the cuff is deflated, the tube is removed. If there is a cough and cyanosis, the tracheobronchial tree is sanitized and artificial ventilation is started using an Ambu bag.

If there is a need for re-intubation, then it should not follow immediately after extubation. First, you need to try to restore the patient's breathing using the Ambu bag, for 3-5 minutes. Only after normalization of the condition is it determined whether re-intubation is necessary. Reintubation is performed after preoxygenation. [7]

Extubation criteria

The endotracheal tube is removed if there is no need to artificially maintain the patency of the airway. According to clinical characteristics, before extubation, the signs of the initial cause of respiratory failure should be mitigated, and the patient himself should have all the prerequisites for normal spontaneous respiration and gas exchange processes. [8]

It is possible to determine that a person is ready for extubation by the following criteria:

• is able to maintain a normal flow of oxygen into the blood while maintaining the ratio of PaO ₂  and FiO ₂  above 150 and 200 with the presence of O ₂  in the inhaled mixture not exceeding 40-50% and the PEEP indicator not exceeding 5-8 mbar;
• is able to maintain the response of the arterial blood environment and the level of carbon dioxide during exhalation within the permissible values;
• successfully passes the test of spontaneous breathing (30-120 minutes with a PEEP of 5 mbar, with a low supporting pressure of 5-7 mbar, with adequate gas exchange and stable hemodynamics);
• the frequency of spontaneous breathing during extubation does not exceed 35 per minute (in an adult);
• the norm of the strength of the respiratory muscles is determined;
• the maximum indicator of negative inspiratory pressure exceeds 20-30 mbar;
• vital lung capacity exceeds 10 ml per kilogram (for newborns - 150 ml per kilogram);
• the indicator of transphrenic pressure is less than 15% of the highest during spontaneous breathing;
• the indicator of spontaneous minute ventilation for an adult at the time of exhalation is 10 ml per kilogram;
• chest compliance exceeds 25 ml / cm;
• respiratory function less than 0.8 J / l;
• the average blood pressure exceeds 80 mm Hg. Art.

The patient must be in a clear consciousness, fulfill certain requests and commands of the doctor. As a test of readiness for extubation, a test such as Gale's tetrad is carried out: the patient is asked to shake hands, raise and hold his head, touch his finger to the tip of his own nose, and hold his breath. [9]

The extubation protocol is a set of diagnostic and tactical algorithms, including a full assessment of the patient's clinical condition, characteristics of the surgical operation, selection of the optimal ventilation scheme and drug support, determination of the readiness to remove the endotracheal tube, and optimization of spontaneous breathing.

The most justified from a physiological point of view are the indicators reflecting the respiratory rate and tidal volume (frequency and volume index), as well as the values of the adaptability of the respiratory system, the maximum inspiratory effort and oxygenation. [10]

Contraindications to the procedure

Experts say that there are no absolute contraindications to extubation. To achieve adequate gas exchange processes, some patients may require:

• non-invasive ventilation of the lungs;
• extended lung inflation (CPAP);
• inhaled mixture with increased oxygen concentration;
• reintubation.

It is necessary to be prepared for the fact that respiratory reflexes may be inhibited immediately after extubation, or a little later. Prevention of possible aspiration is mandatory. [11]

Extubation Removal of the endotracheal tube in a conscious person is usually accompanied by a cough (or motor reaction). The heart rate increases, the central venous and blood pressure increases, as well as intraocular and intracranial pressure. If the patient suffers from bronchial asthma, bronchospasm may develop. The development of complications can be prevented by introducing lidocaine in the amount of 1.5 mg / kg one and a half minutes before extubation.

Removal of the tube under deep anesthesia is contraindicated if there is a risk of aspiration or airway obstruction. [12]

Consequences after the procedure

It is difficult to determine in advance the outcome of extubation, but it is necessary to take into account the fact that both premature and improperly performed manipulation can be fatal for the patient. The likelihood of developing certain consequences depends largely on the qualifications of the doctor, as well as on other background factors. Often, other pathologies in the patient's body, as well as secondary diseases, become the "culprits" of adverse consequences. [13]

To improve the prognosis, it is necessary to monitor the patient, both before and after extubation. It is especially important to monitor the condition of patients who are in terminal conditions, when the likelihood of re-intubation remains high.

The clinical protocol for extubation should include careful monitoring of all vital signs and functions of a person after manipulation, rapid identification and response to respiratory disorders, if necessary, rapid reintubation or tracheostomy. [14]

Tracheal extubation is a key step in recovery from general anesthesia. This is a difficult manipulation that can result in a greater number of complications than the primary intubation procedure. During the removal of the endotracheal tube, the controlled situation turns into an uncontrolled one: specialists are faced with physiological changes along with a limited time period and other constraining factors, which in general can be difficult even for a highly qualified anesthesiologist.

It should be noted that the overwhelming majority of post-extubation complications are insignificant. However, in some cases, doctors have to deal with serious consequences, including cerebral hypoxia and death. [15]

Laryngospasm after extubation

Laryngospasm is the most common cause of upper airway obstruction after extubation. The clinical picture of laryngospasm can be of varying severity and can be represented by both mild stridorious breathing and complete respiratory obstruction. Most often, the complication is found in childhood, against the background of surgical intervention on the organs of the respiratory system. [16]

The most common cause of post-extubation laryngospasm is irritation with salivary secretions or blood, mainly with shallow anesthesia. In such a situation, the patient can neither prevent a reflex response nor clear his throat well. The incidence of post-extubation laryngospasm can be reduced by placing patients on their side and resting until they are fully awakened. In addition, the complication can be prevented by intravenous administration of magnesium sulfate (dosage 15 mg / kilogram for 20 minutes) and lidocaine (dosage 1.5 mg / kilogram). [17]

Complications after the procedure

To prevent complications before extubation, it is imperative to determine the degree of risk to the patient. It is known that the easier the intubation was, the less the likelihood of post-extubation complications.

A special approach is required for prolonged and traumatic operations with large blood loss. In obviously difficult cases, they resort to a phased removal of the endotracheal tube.

One of the basic factors for the success of the procedure is the elimination of residual muscle relaxation. [18]

A high risk of developing complications is said in such cases:

• there are difficulties with ventilation and intubation;
• limited mobility of the cervical spine, mandibular joints, or there is instability in these areas;
• the patient suffers from morbid obesity, has obstructive breath holding during sleep (from anamnesis);
• there are risks of postoperative bleeding and compression of the larynx by a hematoma, or there are facts of damage to the nerve fibers of the larynx or pharynx;
• the intubation was performed “blind”;
• there are massive dressings that can impair air access - for example, in the neck, head, face.

The most common probable complications after extubation are:

• hemodynamic disorders;
• laryngospasm;
• cough, wheezing noisy (stridor) breathing;
• respiratory delay (apnea);
• damage to the vocal cords;
• swelling of the laryngeal tissues;
• pulmonary edema;
• oxygen deficiency;
• aspiration.

The greatest risk is due to the inability to quickly perform reintubation and ensure normal gas exchange during intubation attempts. [19]

Why is it difficult for my baby to breathe after extubation?

One of the complications of extubation can be laryngeal edema, which becomes a serious factor in the development of upper airway obstruction in young children: this manifests itself within six hours after the procedure. The supraglottic edema pushes the epiglottis backward, causing the glottis to block during inhalation. If there is retroaritenoidal edema behind the vocal cords, then this leads to a restriction of their abduction during inspiration. Subglottic edema narrows the cross-section of the laryngeal space. [20]

Additional risk factors for the development of edema after extubation are:

• tightly installed tube;
• intubation trauma;
• long intubation period (more than an hour);
• cough, head and neck movements during intubation.

A similar condition is typical for adult patients - after prolonged translaryngeal intubation.

In case of laryngeal edema, the supply of a humidified heated oxygen-enriched gas mixture is recommended. Epinephrine is fed through a nebulizer, dexamethasone, Heliox are used. In difficult situations, reintubation is performed with a tube with a smaller diameter.

Difficulty breathing after extubation may be associated with hematoma and tissue compression. In such cases, immediate re-intubation and final control of bleeding are practiced. [21]

Another reason is trauma to the respiratory tract caused by rough manipulations, mechanical damage during the insertion or removal of the endotracheal tube. Obstructive symptoms can occur acutely or appear later in the form of swallowing pains or voice changes.

A less common cause of breathing difficulties after extubation is vocal cord paralysis caused by damage to the vagus nerve during surgery. With bilateral paralysis, there is a risk of post-extubation obstruction, so immediate re-intubation is performed.

Care after the procedure

The risk of developing complications after extubation is present not only immediately after the removal of the endotracheal tube, but also during the entire recovery period. Therefore, it is important to ensure maximum attention and monitoring of the patient's condition by the attending physician and anesthesiologist.

An oxygen mask is used during patient transportation to the recovery room. The medical staff fully serves him until the restoration of all respiratory reflexes and the normalization of physiological parameters. Each patient is provided with constant monitoring by nurses and an anesthesiologist. [22]

After removing a person from anesthesia, specialists assess the level of his consciousness, the frequency of respiration and cardiac activity, blood pressure, body temperature and peripheral oxygen saturation. The use of capnography allows early detection of impaired airway patency.

Threatening signs after extubation:

• respiratory disorders in the form of stridor breathing, agitation;
• postoperative complications (pathological drainage discharge, graft perfusion, bleeding and hematoma, airway edema);
• the development of mediastinitis and other respiratory injuries. [23], [24]

Mediastinitis is the result of a perforated injury to the airway - for example, after a difficult tube insertion. The complication is manifested by pain in the chest and neck, impaired swallowing, painful swallowing, fever, crepitus. [25]

Traumatic injuries are most often found in the larynx, pharynx and esophagus. In some cases, pneumothorax and emphysema are noted.

Patients with irritated airways are given an upright position, and humidified oxygen is inhaled with sufficient flow. It is recommended to control the concentration of carbon dioxide during exhalation. The patient is not fed due to a possible violation of the laryngeal function (even with a clear consciousness), exclude factors that can disrupt venous circulation. It is important to ensure deep breathing and free coughing up of phlegm. If the patient has obstructive sleep apnea, then respiratory patency is compensated for by setting a nasopharyngeal airway.

To reduce inflammatory edema after extubation, glucocorticoids (100 mg hydrocortisone every six hours, at least twice) are prescribed. With the development of respiratory obstruction, it is possible to administer 1 mg of adrenaline by means of a nebulizer. A mixture of helium in oxygen also has a positive effect. [26]

Additional medication support includes analgesic and antiemetic therapy.

Reviews

Resumption of spontaneous breathing after extubation is often achieved without particular problems. But in some patients, the activation of the respiratory function is difficult, which requires the use of intensive care measures.

Spontaneous breathing activation is a combined process that requires a multi-stage assessment of an individual clinical case. The mechanics of respiratory capacity, the adequacy of ventilation and oxygen supply to tissues are assessed. The nature of the therapy used, the general and psychological state of the patient, and other existing problems are necessarily taken into account.

The success of extubation largely depends on the skills of the medical staff: it is important to correctly interpret the patient's response to an attempt to activate spontaneous respiratory function.

The duration of a person's stay in the intensive care unit, as well as the frequency of complications due to a long intubation period, depends on the timing of extubation. According to reviews, most patients are relatively quickly transferred to spontaneous breathing. Much fewer patients face difficulties in activating spontaneous respiratory function, which lengthens the length of hospital stay and increases the risk of adverse consequences.

Early extubation is characterized by benefits such as less need for outside care, reduced risk of airway injury, increased cardiac output and increased renal perfusion during spontaneous breathing.