Artificial coma

An artificial coma, from the point of view of clinical medicine, is a temporary immersion of the patient into an unconscious state, in which there is a deep inhibition of the activity of the cortex and subcortex of the brain and a complete shutdown of all reflex functions.

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Causes induced coma

An artificial coma is an extreme measure. It is used only when doctors see no other way to protect the patient's body from irreversible brain changes that threaten his life. These include compression of brain tissue and its swelling, as well as hemorrhages or bleeding that accompany severe craniocerebral injuries or cerebral vascular diseases.

In addition, artificial coma can replace general anesthesia in cases of large-scale emergency operations or complex surgical interventions directly on the brain.

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Symptoms induced coma

Why do they put you into an artificial coma? To slow down the metabolism of brain tissue and reduce the intensity of cerebral blood flow. As a result, the brain vessels narrow and the intracranial pressure drops. In this state, it is possible to relieve swelling of brain tissue and avoid its necrosis.

The introduction of an artificial coma is carried out in the intensive care and resuscitation departments by means of a constant controlled dose of special drugs. Most often these are barbiturates or their derivatives that depress the central nervous system. To immerse a patient in a drug-induced coma, high doses are selected that correspond to the stage of surgical anesthesia.

After the drug starts to work, symptoms of an artificial coma appear:

• complete muscle relaxation and immobilization;
• absence of all reflexes (deep unconsciousness);
• drop in body temperature;
• lowering blood pressure;
• significant decrease in heart rate;
• slowing of atrioventricular conduction;
• blockage of the gastrointestinal tract.

It should be noted that to compensate for the oxygen deficiency that the brain would experience due to a decrease in heart rate, patients are immediately connected to an artificial lung ventilation apparatus (ALV). That is, a breathing mixture of compressed, dried air and oxygen is forcibly supplied to the lungs. As a result, the blood is saturated with oxygen, and carbon dioxide is removed from the lungs.

While the patient is in an artificial coma, the indicators of all his vital functions are recorded by special equipment and are constantly monitored by the anesthesiologist and resuscitation doctors of the intensive care unit.

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Complications and consequences

Neurosurgeons note that the consequences of an artificial coma depend on the reason that necessitated putting the patient into this state.

But many consequences of artificial coma are related to the fact that prolonged artificial ventilation of the lungs (ALV) has many side effects. The main complications affect the respiratory system and are expressed in tracheobronchitis, pneumonia, blockage (obstruction) of the bronchi by adhesions, pneumothorax, narrowing (stenosis) of the trachea, bedsores of its mucous membrane, fistulas in the walls of the trachea and esophagus.

In addition, the consequences of an artificial coma are expressed in disturbances of blood flow through the vessels (hemodynamics), pathological changes in the gastrointestinal tract that has not worked for a long time, renal failure, etc. Numerous cases of neurological disorders in patients after coming out of a state of drug-induced coma are also recorded.

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Diagnostics induced coma

Today, diagnostics of artificial coma is carried out using a whole range of methods.

A mandatory method for determining functional indicators of the brain is monitoring the activity of the cerebral cortex by electroencephalography. In fact, the artificial coma itself is possible only under the condition of constant monitoring of the electroencephalograph, to which the patient is constantly connected.

The method of measuring cerebral blood flow (cerebral hemodynamics) has such methods of assessing microcirculation as local laser flowmetry (with the introduction of a sensor into the brain tissue) and radioisotope measurement of general cerebral circulation.

The state of the patient's brain in an artificial coma is determined by measuring the intracranial pressure in the ventricles of the brain - with the installation of a ventricular catheter in them. The method of assessing metabolism in brain tissues allows us to determine the degree of oxygen saturation and the content of certain components in the venous blood flowing from the brain - by periodically conducting a blood test from the jugular vein.

Also used in the diagnosis of artificial coma are visualization methods, including computed tomography (CT), magnetic resonance imaging (MRI) and positron emission computed tomography (PECT). Together with methods for measuring cerebral blood flow, CT and MRI are used in neuroreanimatology to determine the prognosis of the outcome of artificial coma.

Experts debate when a coma is considered hopeless. In clinical practice in many Western countries, patients with traumatic brain injury who are in a vegetative state for more than six months are considered hopeless. This diagnosis is made based on the identification of the cause of the syndrome, clinical assessment of the patient's condition, and the duration of the coma.

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Treatment induced coma

In this context, the wording “treatment with artificial coma” seems more appropriate to us, since artificial coma is not a disease, but targeted clinical actions for medical reasons.

Such indications include artificial coma after surgery, artificial coma for pneumonia, or artificial coma for stroke.

Thus, an artificial coma after surgery was used on the famous German racing driver Michael Schumacher after he suffered a severe craniocerebral injury while skiing in the Alps in late December 2013. First, he underwent two complex neurosurgical operations, and then was put into an artificial coma.

A month later, doctors at the Grenoble clinic began to bring him out of the artificial coma by reducing the dose of drugs administered. However, the athlete has been in a coma for almost six months now.

And on March 18, 2014, the 50-year-old brother of the Belgian monarch, Prince Laurent, was hospitalized with signs of acute pneumonia. For more effective treatment, doctors placed him in intensive care and put him into an artificial coma for pneumonia. After a two-week comatose state, during which treatment was carried out, he was brought out of the coma in a satisfactory condition.

Among the reasons for artificial coma as a way to reduce the risk of severe consequences of cerebrovascular accident is a cerebral stroke (ischemic or hemorrhagic). With this disease, focal brain damage occurs, the irreversible consequences of which appear literally in a few hours. To avoid this, as well as to remove the thrombus, the patient can be put into an artificial coma. However, this method of treatment is quite risky.

The duration of an artificial coma (not caused by prior surgical intervention) is related to the nature and severity of the injury or disease and can range from several days to several months. And withdrawal from an artificial coma begins only after the consequences of the injury or signs of the disease have disappeared - based on a comprehensive examination of the patient.

Forecast

The most disappointing prognosis for an artificial coma is observed in cases of subarachnoid hemorrhage (which occurs due to a ruptured arterial aneurysm or craniocerebral trauma) and stroke. And the longer a person remains in an artificial coma, the less their chances of recovery.

A study conducted in the UK showed that the consequences of an artificial coma lasting up to one year look like this: 63% of patients died or came out of the coma with irreversible cognitive impairment (at the "plant level"), 27% suffered severe or moderate disability after coming out of the coma, and only 10% of patients recovered in a fairly good condition. This study made it possible to identify four important clinical features that help determine the prognosis of an artificial coma: bradycardia, coma depth, its duration, and such clinical signs as brainstem somatosensory reflexes on the electroencephalogram, blood glucose levels, biochemical parameters of the cerebrospinal fluid, etc.

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