Generality
Pharmacological coma is a reversible state of profound unconsciousness, obtained through controlled doses of drugs; this condition is induced in order to protect the brain in the presence of particularly severe pathological circumstances, which could seriously compromise the health of the central nervous system.
To induce pharmacological coma, the traditionally used drugs are: barbiturates (eg pentobarbital), benzodiazepines, propofol and opiates.
People in a pharmacological coma require continuous medical assistance, especially with regard to vital functions such as breathing (eg: mechanical ventilation) and nutrition (eg: nasogastric tube).
Pharmacological coma is an effective solution, but not without risks; among the latter, a mention certainly deserves: hypotension due to the use of barbiturates and benzodiazepines, and all the complications resulting from prolonged immobilization.
What is pharmacological coma?
Pharmacological coma is a reversible state of profound unconsciousness, induced voluntarily by doctors, through controlled doses of drugs, and having therapeutic purposes.
Also known as induced coma or artificial coma, pharmacological coma is different from that state of profound unconsciousness, simply referred to as "coma" or "pathological coma", which can result from serious health conditions, such as severe head trauma, illness. metabolic diseases, central nervous system diseases, drug poisoning, etc.
Pathological coma
Temporary state of unconsciousness, voluntarily induced by doctors through controlled doses of drugs, in the presence of: severe burns, poisoning, post-traumatic cerebral edema, prolonged lack of oxygen in the brain, major neurosurgery, etc.
Unwanted state of unconsciousness, from which whoever falls into it cannot be awakened. It involves the lack of response to painful stimuli, changes in light and sounds, which causes the sleep-wake cycle to skip and, finally, which makes any voluntary action impossible.
It is possible to awaken the patient from a pharmacological coma by simply stopping the drug administration.
Awakening is something unpredictable, which depends on the severity of the causes that led to the pathological coma and on other factors currently unknown.
There are no intermediate states of unconsciousness or wakefulness between pharmacological coma and consciousness.
Pathological coma can evolve into two very particular waking states, which do not always correspond to an improvement in the situation. These waking states are: the vegetative state and the state of minimal consciousness.
Both pharmacological coma and pathological coma are characterized by the so-called complications of immobilization (aspiration pneumonia, bedsores, thromboembolic disease, etc.)
Patients in pharmacological coma and pathological coma require continuous monitoring of vital functions and support for breathing and nutrition.
HOW TO INDUCE THE PHARMACOLOGICAL COMA? DRUGS
To induce pharmacological coma, doctors and anesthetists use combinations of: barbiturates (pentobarbital or sodium thiopental), benzodiazepines, propofol and opiates.
Such medicines are widely known; some are used, in the medical field, also for other purposes: for example propofol is used, very often, in the realization of anesthesia.
WHERE CAN IT TAKE PLACE?
The induction of pharmacological coma takes place exclusively in the intensive care units of hospitals.
Indications
Various circumstances could make it necessary to resort to pharmacological coma, including:
- Presence of cerebral edema, consequent to head trauma of a certain entity;
- Prolonged lack of oxygen in the brain, resulting for example from cardiac arrest, ventricular fibrillation or stroke;
- Major neurosurgery interventions;
- Critical conditions, such as severe burns, septic shock, or poisoning
- Rupture of a brain aneurysm
- Status epilepticus.
WHY USE THE PHARMACOLOGICAL COMA? ACTION MECHANISM
The cells of the brain tissues need a lot of energy and resources to function at their best: think that, according to various scientific studies, about 60% of the glucose and oxygen present in the human organism would only and exclusively serve the electrical activity of the brain nerve cells (NB: according to the same studies, the remaining 40% would be destined, instead, to the other activities of the organism, such as for example the basal metabolism).
When an individual is the victim of a serious health condition, as can be one of the circumstances that make pharmacological coma indispensable, the cells of the brain tissues begin to suffer first and then to die, as the energies and resources, they need to do their best and survive are less and less. In other words, when a strong stress occurs for the organism, the brain, even if it is not directly affected, begins to suffer in an evident way, because there is a general decrease in vital resources.
Doctors resort to pharmacological coma to protect the brain from the consequences that cerebral edema, lack of oxygen in the brain, major neurosurgery interventions, etc. In fact, the "induction of pharmacological coma temporarily reduces the" activity of the nerve cells of the brain - in practice it is as if it puts them to rest for a certain period of time - and this allows the tissues, which the aforementioned cells compose, to overcome the difficulties and stress deriving from the critical circumstances mentioned by now several times already.
In essence, therefore, the pharmacological coma is a remedy that doctors use to reduce the needs of the brain, when these needs, due to a potentially lethal condition for the body, would not be adequately met.
Drugs for induction of pharmacological coma reduce metabolism and oxygen demands on the part of the brain. In this way, they guarantee the rest of the organism resources, which allow the patient to recover from the serious health condition in which he finds himself.
Patient management
During the pharmacological coma, the continuous monitoring of the patient's vital functions is foreseen by the medical staff (in this case by the anesthetist). This is a precautionary measure, which allows to notice in time any problems, complications, deterioration of the state of health, etc.
In addition, the affected individual needs support for breathing, such as mechanical ventilation, and for feeding, such as a nasogastric tube.
AWAKENING AND DURATION OF THE PHARMACOLOGICAL COMA
Obtained with the interruption of pharmacological administrations based on barbiturates etc., the awakening from the pharmacological coma takes place when the doctors ascertain that the patient is better and is clearly improving.
The severity of the circumstances that made it necessary therefore affects the duration of the pharmacological coma: the more a circumstance is serious from a clinical point of view, the more hypothetical time it will take for the patient to recover, once brought to the pharmacological coma; conversely, the less serious the causal circumstance is, the more the hypothetical times of stay in a pharmacological coma are shortened.
In light of what has been stated, therefore, the duration of the pharmacological coma varies from patient to patient, depending on the causal circumstances (ie the reasons that convinced doctors to resort to induced coma).
REHABILITATION
In the same way as people who come out of a pathological coma, people who wake up from a pharmacological coma need specific treatments, which help to return to a normal life.
The treatments in question include:
- Physiotherapy, essential to remedy muscle contractures resulting from prolonged immobility;
- Occupational therapy, whose field of application ranges from encouraging the patient's reintegration in a social context, to adapting the home environment according to the needs of the person who has just awakened from a pharmacological coma;
- Psychotherapy, the aim of which is to help the patient overcome the early stages of awakening from a profound state of unconsciousness and to make him accept that therapies are needed, in order to return to a normal or almost normal life.
Risks and complications
Drugs such as barbiturates and benzodiazepines tend to dangerously lower blood pressure; therefore, people in a medically induced coma are at risk of hypotension.
To prevent the phenomenon of hypotension, in people in a pharmacological coma, doctors resort to the administration of medicines that raise blood pressure, in order to keep it within the normal range.
Just like people in a pathological coma, individuals in a pharmacological coma run the risk of developing so-called immobilization complications, namely: aspiration pneumonia, pressure sores, thromboembolic disease, etc.
Causes
Prevention
Aspiration pneumonia
- Gastroesophageal reflux, resulting from the prolonged maintenance of a horizontal position.
- Inability to swallow properly.
- Feeding through a tube.
- Keeping the patient in a lateral position.
- Aspiration of saliva at regular intervals.
- Parenteral nutrition.
Bedsores
- Immobility for long periods, with consequent maintenance of a static position.
- Change the position of the bedridden patient every 2-3 hours.
- Use water mattresses, which are more congenial to those forced to long periods of immobility.
- Plan a nutrition adapted to the needs of the human body.
- Monitor favoring conditions (e.g. diabetes, where present.
BARBITURICS AND RISK OF INFECTION
Some past research has advanced the hypothesis that the barbiturates used to induce pharmacological coma caused a lowering of the immune defenses, with a consequent increase in the risk of infection.
Subsequent studies, however, have shown that there is no such strong evidence in favor of the hypothesized consequential relationship between the use of barbiturates for pharmacological coma and the increased risk of infection.
NIGHTMARES AND HALLUCINATIONS
Upon awakening, many people subjected to drug coma report having been victims of hallucinations and nightmares.
According to some experts, hallucinations and pharmacological coma nightmares are due to the attempts made by the patients' brain to perceive something (eg sounds) from the surrounding environment.
Prognosis
In spite of some criticisms against him, the pharmacological coma seems to be a solution of some usefulness and able to work.
However, it should be stressed that it is a path that doctors take in extreme cases, when an individual proves to be in serious health conditions and / or has not responded positively to any other more traditional treatment.
Therefore, if on the one hand the pharmacological coma can represent a possible source of benefit, on the other it must not be forgotten that the patient's hopes for recovery and survival are low. All this makes any predictions on the prognosis uncertain.
Criticisms
Some doctors have begun to doubt the usefulness of pharmacological coma, since several groups of researchers have demonstrated the ineffectiveness of induced coma in circumstances such as: major neurosurgery, cerebral edema from head trauma, rupture of a cerebral aneurysm, ischemic stroke and status epilepticus.
It should be noted, however, that what the aforementioned research groups demonstrated regarding pharmacological coma came from studies that were mostly isolated and in need of further investigation.
