Respiratory arrest

The cessation of gas exchange in the lungs (cessation of breathing) for more than 5 minutes can cause damage to vital organs, especially the brain.

Almost always, cardiac arrest occurs next, if the respiratory function cannot be restored immediately.

[1], [2], [3], [4], [5], [6], [7],

Causes of the stop breathing

Respiratory arrest may be caused by airway obstruction, respiratory depression in neurological and muscular disorders, and drug overdose.

Obstruction of the upper or lower respiratory tract is possible. Children under the age of 3 months usually breathe through the nose. Therefore, they may experience obstruction of the upper respiratory tract in violation of breathing through the nose. At any age, loss of muscle tone in case of disturbed consciousness can lead to obstruction of the upper respiratory tract due to falling of the tongue. Other causes of obstruction of the upper respiratory tract may be blood, mucus, vomit, or foreign body; spasm or swelling of the vocal cords; inflammation of the hypopharynx, trachea; swelling or trauma. In patients with congenital developmental disorders, anomalously developed upper respiratory tract, which is easily subjected to obstruction, is often encountered.

Obstruction of the lower respiratory tract can occur with aspiration, bronchospasm, pneumonia, pulmonary edema, pulmonary hemorrhage and drowning.

The weakening of the respiratory pattern due to central nervous system (CNS) disorders may result from drug overdose, carbon monoxide poisoning or cyanide, CNS infection, heart attack or hemorrhage in the brain stem and intracranial hypertension. The weakness of the respiratory muscles can be secondary to damage to the spinal cord, neuro-muscular diseases (myasthenia, botulism, polio, Guillain-Barre syndrome), the use of drugs that cause the neuromuscular block; with metabolic disorders.

[8], [9], [10], [11],

Symptoms of the stop breathing

When the patient stops breathing, the consciousness is disturbed, the skin becomes cyanotic (if there is no severe anemia). In the absence of help a few minutes after the onset of hypoxia, cardiac arrest occurs.

Until the complete cessation of breathing, patients without neurological disorders may be in a state of excitement, confusion, trying hard to breathe. Tachycardia occurs and sweating increases; intercostal spaces and sternoclavicular articulation can be observed. Patients with CNS disease or respiratory muscle weakness experience weak, difficult, irregular, or paradoxical breathing. Patients with a foreign body in the airways may cough, choke and point to their neck.

In infants, especially under the age of 3 months, apnea can develop acutely without any alarming prerequisites, as a result of the development of an infectious process, metabolic disorders or a high price of respiration.

[12], [13], [14], [15], [16], [17]

Treatment of the stop breathing

Respiratory arrest does not cause diagnostic difficulties; treatment begins simultaneously with its diagnosis. The most important task is the detection of a foreign body, which was the cause of airway obstruction. If present, mouth-to-mouth breathing or a bag through a mask will not be effective. A foreign object can be detected during laryngoscopy with tracheal intubation.

The treatment consists in removing the foreign body from the respiratory tract, ensuring its patency in any way and carrying out mechanical ventilation.

[18], [19], [20], [21], [22],

Providing and controlling airway patency

It is necessary to release the upper airways and maintain air circulation with a mechanical device and / or auxiliary breaths. There are many indications for controlling the airway. In most situations, using a mask can temporarily provide adequate ventilation of the lungs. If carried out correctly, mouth-to-mouth breathing (or mouth-to-mouth-and-nose in infants) can also be effective.

[23], [24], [25], [26], [27]

Sanitation and maintenance of the upper respiratory tract

Obstruction associated with the weakness of the soft tissues of the oropharynx may be temporarily eliminated by the extension of the neck (tilting the head) and the extension of the lower jaw; thanks to these maneuvers, the tissues of the anterior sections of the neck are raised and the space between the tongue and the posterior pharyngeal wall is freed. Ocular oropharyngeal obstruction with a denture or other foreign body (blood, secrets) can be eliminated with fingers or aspiration, however one should be aware of the danger of their displacement in depth (this is more likely in infants and young children who are not allowed to hold this maneuver blindly). Deeper material can be removed with Magill forceps during laryngoscopy.

Heimlich method. The Heimlich method (hand push in the epigastric region, in pregnant and obese people - on the chest) is a method of controlling the airway in patients with consciousness, shock or unconsciousness, with no effect from other methods.

An adult in an unconscious state is laid on his back. The operator sits down over the patient's knees. To prevent damage to the liver and chest organs, the hand should never be located on the xiphoid process or the lower costal arch. Tenar and hypotenar palms are located in the epigastrium below the xiphoid process. The second hand is located on top of the first and there is a strong push in the upward direction. For thrusts of the chest arms are arranged as for a closed heart massage. With both methods, it may take from 6 to 10 quick strong shocks to remove a foreign body.

If there is a foreign body in the airway of an adult patient, the operator becomes conscious in the back, wraps the patient in his hands so that the fist is located between the navel and the xiphoid process, and the second palm clasps the fist. Both hands push inward and upward.

Older children can use the Heimlich method, however, with a weight of less than 20 kg (usually under 5 years old) a very moderate effort must be applied.

In infants less than one year old, the Heimlich method is not used. The infant must be held upside down, supporting the head with one hand, while the other person carries 5 blows to the back. Then it is necessary to carry out 5 pushes in the chest section of the child, while he should lie on his back upside down on the rescuer's thigh. The sequence of blows to the back and chest shocks is repeated until the airway is restored.

[28], [29], [30], [31], [32],

Airways and breathing devices

If spontaneous breathing is absent after the release of the respiratory tract and there are no devices, it is necessary to conduct mouth-to-mouth or mouth-to-mouth-and-nose breathing to save the life of the victim. Exhaled air contains from 16 to 18% O2 and from 4 to 5% CO2 - this is enough to maintain an adequate level of O2 and CO2 in the blood.

The device bag-mask valve (MCM) is equipped with a breathing bag with a valve that does not allow air to be recirculated. This device is not able to maintain the airway, so patients with low muscle tone require additional devices to maintain the airway. MKM ventilation may continue until naso- or orotracheal intubation of the trachea. With the help of this device an additional supply of oxygen is possible. If MKM ventilation is carried out for more than 5 minutes to prevent air from entering the stomach, it is necessary to press on cricoid cartilage to occlude the esophagus.

Situations requiring airway control

Critical	Urgent
Heart failure	Respiratory failure
Respiratory arrest or apnea (for example, in diseases of the central nervous system, hypoxia, medication) Deep coma and tongue obstruction and airway obstruction Acute laryngeal edema	The need for respiratory support (for example, in acute respiratory distress syndrome, exacerbation of COPD or asthma, extensive infectious and non-infectious lesions of the lung tissue, neuromuscular diseases, depression of the respiratory center, excessive fatigue of the respiratory muscles)
Laryngospasm Foreign body of the larynx	The need for respiratory support in patients in shock, with low cardiac output or myocardial damage
Drowning Inhalation of smoke and toxic chemicals	Before washing the stomach in patients with oral drug overdose and impaired consciousness
Respiratory tract burn (thermal or chemical) Aspiration of gastric contents	With a very high consumption of O 2 and limited respiratory reserves (peritonitis)
Trauma to the upper respiratory tract	Before bronchoscopy in critically ill patients
Damage to the head or upper spinal cord	When conducting diagnostic x-ray procedures in patients with impaired consciousness, especially during sedation

A gastric probe is installed to evacuate the air from the stomach, which will definitely get there during the ventilation of the MCM. Pediatric breathing bags have a valve that limits the peak pressure created in the respiratory tract (usually at 35 to 45 cm water. Art.).

Oropharyngeal or nasal air ducts prevent airway obstruction caused by soft tissue. These devices facilitate ventilation with MKM, although they cause vomiting impulses in patients in consciousness. The size of the oropharyngeal airway should correspond to the distance between the corner of the mouth and the angle of the lower jaw.

A laryngeal mask is placed in the lower regions of the oropharynx. Some models have a channel through which an intubation tube can be led into the trachea. This method causes minimal difficulties and is very popular due to the fact that it does not require laryngoscopy and can be used by minimally trained personnel.

The double lumen esophageal-tracheal tube (combitube) has proximal and distal cylinders. It is installed blindly. Usually it enters the esophagus and in this case, ventilation is carried out through one hole. When it enters the trachea, the patient is ventilated through another opening. Technique staging this tube is very simple and requires minimal training. This technique is unsafe for long-term use, so it is necessary to undergo tracheal intubation as soon as possible. This method is used only at the prehospital stage as an alternative to an unsuccessful attempt to tracheal intubation.

The endotracheal tube is critical in case of damage to the airways, for the prevention of aspiration and mechanical ventilation. Through it is the rehabilitation of the lower respiratory tract. When installing the endotracheal tube, laryngoscopy is necessary. Tracheal intubation is indicated for patients in a coma and those in need of prolonged mechanical ventilation.

[33], [34], [35]

Endotracheal intubation

Before tracheal intubation, it is necessary to provide airway, ventilation and oxygenation. Orotracheal intubation is preferable in severe patients and in apnea, as it is performed faster than nasotracheal. Nasotracheal tracheal intubation is more commonly used in patients with preserved consciousness, spontaneous breathing, when comfort is a priority.

Large endotracheal tubes have large volume and low pressure cuffs that minimize the risk of aspiration. Cuffed tubes are used in adults and children over 8 years old, although in some cases they can be used in infants and young children. For most adults, tubes with an internal diameter equal to or greater than 8 mm are suitable; they are preferable to tubes of smaller diameter. They have lower resistance to air flow, they allow for a bronchoscope and facilitate the process of weaning from mechanical ventilation. The cuff is inflated with a 10 ml syringe, and then the pressure in the cuff is adjusted with a pressure gauge, which should be below 30 cm of water. Art. For children up to 6 months the diameter of the tubes is 3.0-3.5 mm; from 6 months to a year - 3.5-4.0 mm. For children older than one year, the tube size is calculated using the formula (age in years + 16) / 4.

Before intubation, the uniformity of inflation of the cuff and the absence of air leakage are checked. For conscious patients, inhalation of lidocaine makes manipulation more comfortable. Sedation, vagolytic drugs and muscle relaxants are used in both adults and children. You can use a straight or curved blade laryngoscope. Direct blade is preferable to use in children under 8 years of age. The technique of visualization of the glottis for each blade is somewhat different, but in any case, it must be able to clearly visualize it, otherwise esophageal intubation is likely. To facilitate the visualization of the glottis, pressure on cricoid cartilage is recommended. In pediatric practice, it is recommended to always use a removable conductor for the endotracheal tube. After orotracheal intubation, the conductor is removed, the cuff is inflated, a mouthpiece is installed and the tube is fixed to the corner of the mouth and upper lip with a plaster. Using an adapter, the tube is connected to a breathing bag, a T-shaped humidifier, an oxygen source or a ventilator.

When the endotracheal tube is properly installed, the chest should be lifted evenly with manual ventilation, during auscultation of the lungs breathing should be carried out symmetrically on both sides, there should be no extraneous noise in the epigastrium. The most reliable way to determine the correct position of the tube is to measure the concentration of CO2 in exhaled air, its absence of CO2 in a patient with preserved blood circulation indicates esophageal intubation. In this case, it is necessary to perform intubation of the trachea with a new tube, after which the previously installed tube is removed from the esophagus (this reduces the likelihood of aspiration when the tube is removed and regurgitation occurs). If breathing is weakened or absent above the surface of the lungs (usually left), the cuff is deflated and the tube is tightened by 1-2 cm (0.5-1 cm in infants) under constant auscultatory control. If the endotracheal tube is properly installed, the centimeter mark at the level of incisors or gums should be three times the size of the internal diameter of the tube. X-ray examination after intubation confirms the correct position of the tube. The end of the tube should be 2 cm below the vocal cords, but above the trachea bifurcation. For the prevention of tube displacement, regular auscultation of both lungs is recommended.

Additional devices can facilitate intubation in difficult situations (trauma of the cervical spine, massive facial trauma, anomalies of the respiratory tract). Sometimes a conductor with light is used, with the correct position of the tube, the skin above the larynx begins to be highlighted. Another method is retrograde conduction into the mouth of the conductor through the skin and the cricoid membrane. Then, along this conductor, the endotracheal tube is inserted into the trachea. Another method is the intubation of the trachea with a fibroscope, which is carried out through the mouth or nose into the trachea, and then the intubation tube slides over it into the trachea.

[36], [37], [38], [39],

Nasotraheial intubation

Nasotracheal intubation may be performed in a patient with spontaneous breathing stored without laryngoscopy, which may be required in a patient with an injury to the cervical spine. After local anesthesia of the nasal mucosa and through it, the tube is slowly held to a position above the larynx. When you inhale, the vocal cords open and the tube is quickly held in the trachea. However, due to anatomical differences in the airways, this method is usually not recommended.

[40]

Surgical methods for the restoration of airway patency

If a foreign body or massive injury caused an obstruction of the upper respiratory tract or other methods could not restore ventilation, it is necessary to resort to surgical methods to restore the airway.

Cricothyrotrophy can only be used in emergency situations. The patient lies on his back, a cushion is placed under the shoulders and the neck is unbent. After treating the skin with antiseptics, the larynx is held in one hand, an incision is made in the skin, subcutaneous tissues and the cricoid membrane of the membrane with a blade exactly along the midline before entering the trachea. Through the hole in the trachea is held corresponding to the size of the tracheostomy tube. In community-acquired conditions, when life threatens, you can use any suitable hollow tube to restore air passage. If other equipment is not available, you can use an intravenous catheter of 12G or 14G. While holding the larynx with the hand, the catheter is guided through the ring-thyroid membrane along the median line. Conducting an aspiration test reveals damage to large vessels; during its passage into the lumen of the trachea, it is necessary to remember about the possibility of perforation of the posterior wall of the trachea. The correct position of the catheter is confirmed by the aspiration of air through it.

Tracheostomy is a more complicated procedure. It should be carried out by a surgeon in the operating room. In emergency situations, there are more complications when performing a tracheostomy than when performing cryochototomy. If necessary, prosthetic breathing for more than 48 hours, preferably a tracheostomy. An alternative for severely ill patients who cannot be transported to the operating room is percutaneous puncture tracheostomy. The tracheostomy tube is inserted after puncture of the skin and the sequential introduction of one or more dilators.

[41], [42]

Complications of intubation

During tracheal intubation, it is possible to damage the lips, teeth, tongue, epiglottis, and laryngeal tissue. Intubation of the esophagus in conditions of mechanical ventilation may lead to stretching of the stomach (rarely breaking it), regurgitation and aspiration of the stomach contents. Any endotracheal tube causes stretching of the vocal cords. Subsequently, laryngeal stenosis may develop (usually at 3–4 weeks). Rare complications of tracheostomy can be bleeding, thyroid damage, pneumothorax, recurrent nerve damage and important vessels.

Rare complications of intubation are hemorrhages, fistulas and tracheal stenosis. With high pressure in the cuff of the endotracheal tube, erosions can occur on the tracheal mucosa. Properly chosen tubes with large-volume and low-pressure cuffs, regular monitoring of the pressure in the cuff can reduce the risk of ischemic necrosis.

[43], [44], [45], [46], [47], [48]

Preparations used in intubation

With apnea in the absence of a pulse or consciousness, it is possible (and necessary) to perform intubation without premedication. For the remaining patients, premedication is performed, which makes it easier to perform intubation and minimize discomfort during this procedure.

Premedication If the patient's condition allows, oxygenation of 100% 0 ₂ is carried out in advance for 3-5 minutes; This will ensure adequate oxygenation during apnea for 4 to 5 minutes.

Laryngoscopy causes activation of the sympathetic system, accompanied by an increase in heart rate, increased arterial and, probably, intracranial pressure. To weaken this response, 1-2 minutes before sedation and myoplegia, lidocaine is administered intravenously at a dose of 1.5 mg / kg. In children and adults, intubation often exhibits a vagal reaction (marked bradycardia), so atropine 0.02 mg / kg is administered intravenously (at least 0.1 mg to infants; 0.5 mg to children and adults). Some doctors include in premedication a small amount of muscle relaxant, for example, vecuronium 0.01 mg / kg intravenously in patients older than 4 years to prevent the appearance of muscle fastsikulyatsy caused by the introduction of a full dose of succinylcholine. Upon awakening as a result of fasciculations, muscular pain and transient hyperkalemia may occur.

Sedation and analgesia. Laryngoscopy and intubation cause discomfort, therefore, immediately before the procedure, sedative or sedative-analgesic short-acting drugs are injected intravenously. After that, the assistant presses on the cricoid cartilage (Sellick technique), pinches the esophagus to prevent regurgitation and aspiration.

It can be applied etomidate (Etomi-date) at a dose of 0.3 mg / kg (non-barbiturate hypnotic, its use is preferable) or fentanyl at a dose of 5 mg / kg (2-5 mg / kg in children; this dose exceeds the analgesic) - an opioid ( having analgesic and sedative effects), which has sufficient effect and does not cause cardiovascular depression. However, with the introduction of large doses, chest stiffness may develop. Ketamine at a dose of 1-2 mg / kg is an anesthetic with a cardiac stimulant effect. This drug on awakening can cause hallucinations or inappropriate behavior. Thiopental at a dose of 3-4 mg / kg and methohexital (Methohexital) at a dose of 1-2 mg / kg have a good effect, but cause hypotension.

Myoplegia. Relaxation of skeletal muscles greatly facilitates tracheal intubation.

The action of succinylcholine (1.5 mg / kg intravenously, 2.0 mg / kg for infants), a muscle relaxant of depolarizing action, occurs very quickly (30 s - 1 min) and does not last long (3-5 min). It is usually not used in patients with burns, crush muscles (more than 1-2 days old), spinal cord injuries, neuromuscular diseases, renal failure, and probably penetrating eye injury. In 1/15 000 cases of succinylcholine administration, malignant hyperthermia may occur. In children, succinylcholine must be used together with atropine to prevent marked bradycardia.

Non-polarizing muscle relaxants have a longer duration (more than 30 minutes) and a slower onset of action. These include Atracurium 0.5 mg / kg, Mivacurium 0.15 mg / kg, Rocuronium 1.0 mg / kg, Vecuronium 0.1-0.2 mg / kg, which are administered for 60 s.

Local anesthesia. Intubation in patients with consciousness requires anesthesia of the nasal passages and pharynx. Benzocaine, Tetracaine, Butyl Aminobenzoate, and Benzalkonium prefabricated aerosols are commonly used. Alternatively, a 4% lidocaine solution can be injected through the face mask by aerosol.

[49], [50], [51], [52], [53], [54],