Asphyxia is a state of suffocation accompanied by a critical drop in oxygen levels (hypoxia) and an excess of carbon dioxide (hypercapnia) in the blood and tissues. With asphyxia, the phenomena of respiratory insufficiency increase acutely or subacutely: cyanosis of the skin, tachypnea, participation in breathing of auxiliary muscles; in the terminal stage, coma, convulsions, respiratory arrest and cardiac activity develop. The state of asphyxia is diagnosed based on the assessment of complaints and physical data, pulse oximetry. In this case, emergency care is required, which includes restoration of airway patency, oxygen inhalation, tracheotomy, ventilator, drug therapy.
ICD 10
R09.0 T71
Meaning
Asphyxia is a life–threatening condition associated with impaired gas exchange, the development of hypoxic and hypercapnic syndromes and leading to respiratory and circulatory disorders. The basis of asphyxia may be a dysfunction of the respiratory center, a mechanical obstacle to the entry of air into the lungs, damage to the respiratory muscles. All types and forms of asphyxia, regardless of the causes, require urgent (and sometimes resuscitation) measures, since death can occur within a few minutes after the development of acute oxygen starvation. In medicine, the problem of asphyxia is relevant for neonatology, pulmonology, traumatology, toxicology, intensive care and other disciplines.
Asphyxia causes
All causes leading to an asphyxic condition can be divided into pulmonary and extrapulmonary. The first of them are most often associated with external compression of the airways or their intraluminal obstruction (obturation). Compression of the airways from the outside is observed during strangulation (hanging, strangulation with a noose or hands), compression of the trachea, neck injuries, etc. Obstructive respiratory disorders are most often caused by tongue entrapment, blockage of the trachea and bronchi by foreign bodies, intraluminal tumors, ingestion of food, vomit, water during drowning, blood during pulmonary bleeding. Acute stenosis of the respiratory tract can develop with tracheobronchitis, an asthmatic attack, allergic edema or burn of the larynx, swelling of the vocal cords. Also, the pulmonary causes of asphyxia include gas exchange disorders caused by acute pneumonia, massive exudative pleurisy, total pneumothorax or hemothorax, atelectasis or pulmonary edema, PE.
Among the extrapulmonary factors of asphyxia, the conditions leading to the defeat of the respiratory center are leading: intoxication, traumatic brain injuries, stroke, overdose of drugs and narcotic drugs (for example, morphine, barbiturates). Paralysis of the respiratory muscles, as a cause of asphyxia, can develop against the background of infectious diseases (botulism, polio, tetanus), poisoning with curare-like drugs, spinal cord injury, myasthenia gravis, etc. Violations of oxygen transport in tissues occur with massive bleeding, circulatory disorders, carbon monoxide poisoning, methemoglobin-forming agents.
Traumatic asphyxia is based on compression or damage to the chest, which complicates respiratory excursions. Asphyxia caused by insufficient oxygen content in the inhaled air can develop with prolonged stay in poorly ventilated mines and wells, with altitude sickness, with a violation of oxygen supply to limited closed systems (for example, in divers). Fetoplacental insufficiency, intracranial birth injuries, aspiration of amniotic fluid most often lead to asphyxia of newborns.
Pathogenesis
The mechanism of asphyxia development in all types of suffocation has common pathogenetic features. The consequence of oxygen deficiency is the accumulation of incomplete oxidation products in the blood with the development of metabolic acidosis. Severe violations of biochemical processes develop in cells: the amount of ATP sharply decreases, the course of redox processes changes, the pH decreases, etc. The consequence of proteolytic processes is autolysis of cellular components and cell death. First of all, irreversible changes develop in the brain cells, and when the respiratory and vasomotor centers are damaged, death quickly occurs. In the heart muscle with asphyxia, edema, dystrophy and necrosis of muscle fibers occur. On the part of the lungs, alveolar emphysema and edema are noted. Fine-spotted hemorrhages are found in the serous membranes (pericardium, pleura).
Classification
Depending on the rate of development of suffocation (respiratory and hemodynamic disorders), acute and subacute asphyxia are distinguished. According to the mechanism of occurrence , it is customary to distinguish the following types of asphyxia:
- mechanical – restriction or termination of air access to the respiratory tract caused by their compression, obturation or narrowing;
- toxic – suffocation develops as a result of depression of the respiratory center, paralysis of the respiratory muscles, disruption of oxygen transport by blood as a result of chemical compounds entering the body;
- traumatic – suffocation is a consequence of closed chest injuries.
Another classification option suggests separating asphyxia from compression (compression and strangulation – strangulation), asphyxia from closure (aspiration, obturation, drowning) and asphyxia in a confined confined space. A special type of suffocation is asphyxia of newborns, considered in the framework of pediatrics.
Asphyxia symptoms
There are four phases in the clinical course of asphyxia. The first phase is characterized by a compensatory increase in the activity of the respiratory center in conditions of lack of oxygen. During this period, the patient experiences fright, anxiety, excitement; dizziness, cyanosis of the skin, inspiratory shortness of breath with forced inhalation; tachycardia, increased blood pressure. With asphyxia caused by compression or violation of the patency of the respiratory tract, the patient coughs violently, wheezes, attempts to free himself from the squeezing factor; the face becomes puffy, purplish-blue.
In the second phase, against the background of exhaustion of compensatory reactions, shortness of breath becomes expiratory (exhalation increases and lengthens), cyanotic skin color increases, the frequency of respiratory movements and heart contractions decreases, blood pressure decreases. In the third, preterminal phase, there is a short-term cessation of the activity of the respiratory center: episodes of apnea occur, blood pressure drops, reflexes fade, loss of consciousness and coma develop. In the last, fourth phase of asphyxia, agonal breathing is observed, convulsions are noted, pulse and blood pressure are not determined; involuntary urination, defecation and ejaculation are possible.
With gradually developing asphyxia (for several hours or days), the victim sits with his torso bent and his neck stretched forward; he greedily catches air with his mouth wide open, his tongue is often stuck out. The skin is usually pale, acrocyanosis of the lips and nails is pronounced; the fear of death is displayed on the face. During decompensation, asphyxia acquires the stage course described above.
Complications
Asphyxia is complicated by ventricular fibrillation, edema of the lungs and brain, traumatic shock, anuria. Pregnant women may have a spontaneous miscarriage. The cause of death of the patient is usually paralysis of the respiratory center. In acute development, death occurs after 3-7 minutes. In the long-term period, patients who have experienced asphyxia may experience aspiration pneumonia, paresis of the vocal cords, various types of amnesia, changes in emotional status (irritability, indifference), intellectual disorders up to dementia.
Diagnostics
In acute cases and with a known cause, the diagnosis of asphyxia is not difficult. If the patient is conscious, he may complain of dizziness, shortness of breath, darkening of the eyes. Objective data depend on the phase of asphyxia. Pulse oximetry allows you to determine the magnitude of the pulse and the degree of saturation of hemoglobin with oxygen. To identify and eliminate the pulmonary causes of asphyxia, a consultation of a pulmonologist, sometimes an endoscopist, is required. In other cases, traumatologists, neurologists, infectious diseases specialists, toxicologists, psychiatrists, narcologists, etc. may be involved in the diagnosis. The diagnostic stage should be as short as possible in time, since it is often virtually impossible to conduct an in-depth examination (radiography, diagnostic bronchoscopy, etc.) due to the severity of the patient’s condition.
Pathomorphological signs indicating that death occurred from asphyxia are cyanosis of the face, conjunctival hemorrhages, cadaverous spots of bluish-purple color with multiple ecchymoses, a liquid state of blood, stagnation of blood in the right parts of the heart with an empty left half, blood filling of internal organs, etc. In case of strangulation, a strangulation furrow from the compression loop is visible on the neck, fractures of the cervical vertebrae are determined.
Asphyxia treatment
The complex of urgent measures is determined by the cause and phase of asphyxia. In case of mechanical suffocation, first of all, it is necessary to restore the patency of the airways: remove accumulated mucus, blood, water, food masses, foreign bodies using tracheal aspiration, bronchoscopy, special techniques; loosen the noose squeezing the neck, eliminate tongue entanglement, etc. In the absence of independent breathing and cardiac activity, they proceed to cardiopulmonary resuscitation – artificial respiration and closed heart massage. If there are indications and technical possibilities, tracheostomy or tracheal intubation can be performed with the transfer of the patient to a hardware ventilator. The development of ventricular fibrillation serves as the basis for electrical defibrillation.
In some cases, thoracocentesis or drainage of the pleural cavity are the primary measures to eliminate asphyxia. In order to reduce venous pressure, bloodletting is performed. First aid for toxic asphyxia is the introduction of antidotes. After the restoration of lung ventilation and cardiac activity, medical correction of the water-electrolyte and acid-base balance is performed, maintenance of the function of the cardiovascular and respiratory systems, dehydration therapy (to prevent swelling of the brain and lungs), blood transfusion and blood-substituting solutions (with abundant blood loss). If the cause of asphyxia were other diseases (infectious, nervous, etc.), it is necessary to carry out their pathogenetic treatment.
Prognosis and prevention
With acute progressive asphyxia, the prognosis is extremely serious – there is a high risk of death; with prolonged development, it is more favorable. However, even in cases where it is possible to restore vital functions, the effects of asphyxia can make themselves felt in the near or distant time after the patient leaves the critical condition. The outcome of asphyxia is largely determined by the timeliness and volume of resuscitation measures. Prevention of asphyxia is the prevention of situations that can cause suffocation: early treatment of potentially dangerous diseases, prevention of chest injuries, aspiration of liquid substances and foreign objects, suicide; exclusion of contact with toxic substances (including treatment of substance abuse and drug addiction), etc. After asphyxia, patients often require careful care and long-term supervision by specialists.