Mechanical asphyxia is one of the forms of mechanical asphyxia resulting from compression of blood vessels and respiratory tract in the upper parts. It is a consequence of strangulation using a self-tightening loop or garrote. It is accompanied by the development of seizures, loss of consciousness, impaired or stopped breathing, involuntary defecation and urination, diffuse cyanosis of the skin. With compression for more than 4-5 minutes, death occurs. Pathology is diagnosed visually by the presence of characteristic symptoms and a strangulation furrow. Specific treatment: neck release, provision of adequate breathing with the help of ventilator or oxygen insufflation, total relaxation with curare-like drugs, symptomatic therapy.
Mechanical asphyxia (strangulation) is characterized by a sharp weakening of blood flow in the brain, a decrease in oxygen concentration, severe hypoxia. Depending on the type of loop used, it may be complete or incomplete. It is diagnosed during attempts to hang or as a result of criminal actions. The number of cases of suicidal strangulation increases in spring and autumn, during the period of exacerbation in psychiatric patients and the high prevalence of depressive states. About 70% of people who have chosen this method of suicide are men. Situations related to criminal offenses are more likely to occur in large cities.
The immediate cause of mechanical asphyxia is mechanical compression of the upper respiratory tract and blood vessels with a suffocating object, which can be a self—tightening or non-self-tightening loop, a garrote. In this case, there is a mechanical obstacle to the passage of blood to the brain, the integrity of the cartilaginous rings of the trachea is violated. Criminogenic strangulation occurs during robbery, attempted murder. The following factors predispose to suicidal attempts:
- Problems in your personal life. Such motives are more common in people aged 15-29 years. Teenagers who have difficulties in relationships with their parents, suffer from unrequited love and are in sects of various orientation are trying to commit suicide. This is due to the age or constitutional immaturity of the psyche, the desire to get away from existing difficulties.
- Mental illness. Suicide attempts in psychiatric diseases are widespread, their number reaches 50% of the total number of cases. People who are in the manic stage of MDR, who have diagnosed schizophrenia and alcoholic psychosis, who are not aware of their actions, are trying to kill themselves. More often, suicidal attempts occur with exacerbations.
- Desperate situations. The circumstances in which suicide is possible include bankruptcy, poverty, loss of the only source of income, loss of housing or the possibility of acquiring it. Voluntary retirement from life is often committed by people who fear punishment for committed acts that are under threat of criminal prosecution, including life or, in their opinion, an excessively long term of imprisonment.
- Psychological stress. There are cases when self-hanging was committed by people who recently experienced divorce, were sexually assaulted, forced to perform an action unacceptable to them (murder, betrayal). There may be other reasons, united by the presence of a strong psychological shock, which the victim was unable to survive.
- Severe somatic diseases. A significant number of suicidal attempts are made by patients suffering from incurable oncological processes. Suicide among such patients is a way to accelerate the inevitable, to stop the torment arising from a pronounced pain syndrome. Independent termination of existence is also practiced by patients who have a pathology that reduces the quality of life: blindness, paralysis of the limbs.
Strangulation can be complete or incomplete. In the first case, the body is entirely in the air, in the second it partially rests on some surface. Death or severe hypoxia can occur in both situations, since the carotid arteries are squeezed already at a load of 4-5 kg, vertebral — 15-20 kg. With a shock force (jumping from a stool) and a low location of the suffocating agent, a fracture of the hyoid bone and half-rings of the trachea occurs. Smooth tightening of the loop does not lead to such consequences.
At the moment of stopping the blood flow, gas exchange disorders of the type of hypoxemia and hypercapnia rapidly increase, there is a short-term spasm of the vascular network with its subsequent persistent expansion. There is a significant increase in venous pressure in the cerebral basins. Upon autopsy, multiple small hemorrhages are found in the retrobulbar tissue, the thickness of the sternomastoid subclavian muscles and intervertebral discs. Ruptures of the intima of the carotid arteries, areas of necrosis of brain tissue (ischemic stroke) may be detected.
Mechanical asphyxia leads to death in several stages. Each of them lasts 30-60 seconds. Sometimes the process takes up to 10 minutes. The duration of the period preceding the onset of clinical death depends on the localization of the garrote, the mechanical properties of the material of which the loop consists, and the thickness of the traumatic agent. The fastest way a person dies is when the furrow is located above the larynx. In this case, there is compression of the carotid sinuses, collapse of blood vessels and reflex respiratory arrest. The consequences of strangulation directly depend on the stage at which it was interrupted. Specialists in the field of clinical resuscitation distinguish the following degrees of asphyxia:
- I degree. It is characterized by the appearance of tachycardia, signs of moderate respiratory insufficiency, cyanosis of the skin, participation in the breathing process of intercostal muscles, fluttering of the wings of the nose, an increase in arterial and venous pressure. Consciousness is preserved, the mental state can be changed. In most cases, it has no long-term consequences.
- II degree. Develops after 2-3 minutes with complete strangulation and after 1-2 minutes with incomplete. Breathing is rare, muscle cramps are present. Involuntary urination, bowel emptying may occur. Consciousness is lost or the patient is in deep deafness. Those rescued at this stage further develop sensitivity disorders, moderate neurological changes.
- III degree. The duration varies from a few seconds to 1-2 minutes. There is a temporary respiratory arrest, this phenomenon is called a terminal pause. Convulsive muscle contractions and sphincter atony persist, blood pressure decreases to critically small and undetectable values. Diffuse cyanosis is increasing. Patients who have undergone resuscitation subsequently suffer from severe disorders of the central nervous system.
- IV degree. Independent breathing resumes, but has a pathological character (Cheyne-Stokes or Kussmaul). After a few minutes, its complete cessation occurs. Accompanied by cardiac arrest. Clinical death is diagnosed. In patients who were saved, symptoms of post-resuscitation disease, neurological deficit, and in some cases brain death (decortication) are detected.
After removal of the traumatic factor, strangulation leads to the appearance of a certain symptom complex. Most patients have no consciousness. While maintaining it, a person behaves inadequately, sometimes aggressive. The exception is cases of strangulation, which was interrupted at the first stage. There is a characteristic trace of trauma on the neck — a strangulation furrow. Skeletal muscles are tense, continuous convulsions are noted. Petechial rash is found on the sclera and conjunctiva of the eye, as well as on the mucous membrane of the mouth, the upper and intermediate roller of the furrow.
The patient’s breathing is arrhythmic, sometimes intermittent. When strangling with the help of non-tightening loops, anisocoria develops, provoked by unilateral compression of the sympathetic nerve. The examination reveals a positive symptom of Minovich — biting the tip of the tongue with the front teeth during seizures. Sucrovichnaya fluid is released from the nasal passages, blood pressure is elevated or sharply reduced, tachycardia, coronary rhythm disturbance occurs.
A common complication of mechanical asphyxia is posthypoxic encephalopathy. It occurs in more than 70% of people who have undergone strangulation of the II-IV degree. The severity of the consequences directly depends on the stage at which the victim was rescued, and the time it took to correct the gas composition of the blood. Pathology is manifested by chronic headaches, decreased mental abilities, mental instability, panic attacks or bouts of aggression.
The defeat of the central nervous system becomes the cause of somatic failures. 20-40% of people develop paralysis and paresis of varying degrees. There may be a violation of the functions of the upper or lower extremities, the body. Persons who have suffered a fracture of the cartilaginous structures of the trachea, subsequently, in 80% of cases, have difficulty breathing, URT stenosis may occur, a tendency to bronchospasm. Such complications are rarely eliminated. The vast majority of patients are exposed to a significant drop in the quality of life, sometimes patients make repeated suicide attempts provoked by deterioration of health.
The diagnosis of mechanical asphyxia is made on the basis of anamnestic data and the clinical picture available at the time of examination. The environment also allows the ambulance doctor who arrived at the scene to determine what happened: the remains of a loop on the ceiling, a suicide note, traces of defecation on the victim’s clothes. Laboratory examination is carried out in a hospital to determine the severity of homeostasis disorders. Visualizing techniques allow us to establish the fact of mechanical destruction of neck formations. The plan of work with the patient includes the following points:
- Laboratory examination. The analysis for ABB, the concentration of gases in the blood is shown. The CO2 content is increased, the oxygen concentration is reduced. There are signs of metabolic acidosis — a decrease in pH <7.3. If at the prehospital stage the patient was intubated and transferred to a ventilator, the saturation index may be normal or close to normal.
- Hardware inspection. X—ray of the neck is performed, if necessary and technically possible – computed tomography of the affected area. During CT, it is possible to create a three-dimensional layered image of the required area, thereby determining not only the presence, but also the exact localization of damage caused by compression.
- Psychiatric examination. People who have attempted suicide are recommended to consult a psychiatrist. During the conversation, the doctor identifies the reasons for the decision to die, determines the level of adequacy of the patient. Patients with signs of persistent disorders (aggression, depressive states, behavior inconsistency with the surrounding environment) are subject to further treatment in a hospital of the appropriate profile.
Treatment consists of two stages — prehospital and hospital. The first one continues from the moment the victim is found until he is taken to the hospital. The effect of the suffocating factor should be stopped as soon as possible. The patient must be laid on his back, assess the condition. Inadequate independent breathing or its absence is an indication for tracheal intubation. If the patient cannot be intubated, a conicotomy is used. Ventilation is carried out in the mode of small hyperventilation with the oxygen content in the mixture at the level of 60-70%. It requires the introduction of benzodiazepines, crystalloid solutions, sodium bicarbonate, diuretics and prednisone. Transportation is carried out after fixing the neck with a collar tire.
In the hospital, the anesthesiologist-resuscitator continues the rehabilitation measures initiated by the ambulance team. The patient is placed in the ICU, connected to a ventilator. Artificial ventilation is continued for at least 4 hours, more often up to 2-3 days. Heparin is used to relieve hypercoagulation, seizures are considered an indication for complete muscle relaxation due to peripheral muscle relaxants. Massive infusion therapy is carried out, correction of metabolic failures. On the first day, round-the-clock monitoring of vital functions with the help of an anesthesiological monitor is required. If the patient is conscious, a soft fixation to the bed or an individual nursing post is recommended (prevention of suicide relapses).
Prognosis and prevention
The prognosis for life is favorable. In the absolute majority of cases, the victim found before the moment of cardiac arrest can be saved. Recovery can be incomplete. Delayed consequences occur in almost all patients who have undergone strangulation of the second or more degree. The severity of long-term pathology depends on the severity and duration of brain hypoxia, the location and properties of the loop, neurological or mental diseases that existed before suicide.
Mechanical asphyxia of a criminogenic nature, for obvious reasons, is not amenable to medical prevention. Suicidal attempts are prevented by careful observation of others. This task is assigned to the relatives and loved ones of each person. There should be a well-organized psychological assistance service, the work of support groups for people in difficult life situations. It is recommended to include a psychiatrist’s examination in all types of medical examinations and professional medical commissions.