Generality
Pharmacological coma is a reversible state of profound unconsciousness, obtained by 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 drugs traditionally used are: barbiturates (eg: pentobarbital), benzodiazepines, propofol and opiates.
People in a pharmacological coma need 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 risk-free; among the latter, they certainly deserve a mention: 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, the pharmacological coma is different from the state of deep unconsciousness, simply called " coma " or " pathological coma ", which can derive from serious health conditions, such as severe head trauma, diseases advanced metabolic disorders, diseases of the central nervous system, drug intoxications, etc.
| Table . Differences and analogies between pharmacological coma and pathological coma (ie state of coma resulting from pathological conditions). | |
| Induced coma | Pathological coma |
Temporary state of unconsciousness, induced voluntarily 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 interventions, etc. | Unwanted state of unconsciousness, from which those who fall into it cannot be awakened. It involves the failure to respond to painful stimuli, changes in light and sounds, which makes the sleep-wake cycle jump and, finally, which makes any voluntary action impossible. |
It is possible to awaken the patient from the pharmacological coma by simply interrupting the pharmacological administrations. | Awakening is something unpredictable, which depends on the severity of the causes that led to the pathological coma and other factors currently unknown. |
Between the pharmacological coma and consciousness there are no intermediate states of unconsciousness or waking. | The 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 least consciousness . |
Both the pharmacological coma and the pathological coma are characterized by the so-called immobilization complications (aspiration pneumonia, pressure sores, thromboembolic disease, etc.) | |
Patients in pharmacological coma and pathological coma require continuous monitoring of vital functions and support for breathing and feeding. | |
HOW TO INDICATE THE PHARMACOLOGICAL COMA? DRUGS
To induce pharmacological coma, doctors and anesthesiologists use associations of: barbiturates ( pentobarbital or thiopental sodium ), benzodiazepines, propofol and opiates .
These medicines are widely known; some find employment in the medical field, also for other purposes: for example propofol is used, very often, in the realization of anesthesia.
WHERE CAN IT HAVE SITE?
The induction of pharmacological coma is held exclusively in intensive care units in hospitals.
Indications
Various circumstances could make the use of pharmacological coma indispensable, including:
- Presence of cerebral edema, consequent to cranial traumas of a certain entity;
- Prolonged lack of oxygen in the brain, resulting for example from a cardiac arrest, a ventricular fibrillation or a stroke;
- Major neurosurgery interventions;
- Critical conditions, such as severe burns, septic shock or poisoning ;
- Rupture of a brain aneurysm ;
- Status epilepticus .
WHY SHOULD YOU USE THE PHARMACOLOGICAL COMA? MECHANISM OF ACTION
The cells of the encephalic tissues need a lot of energy and resources to work at their best: think that, according to several scientific studies, about 60% of the glucose and oxygen present in the human body would only and exclusively serve the electrical activity of the encephalic nerve cells (NB: according to the same studies, the remaining 40% would be destined, instead, to the other activities of the organism, as for example the basal metabolism).
When an individual is a victim of a serious health condition, as may be one of the circumstances that make pharmacological coma indispensable, the cells of the encephalic tissues first begin to suffer and then die, as the energies and resources, they need to do their best and survive, they are always less. In other words, the occurrence of a strong stress for the organism, the encephalon, even if it is not directly affected, begins to be clearly affected, because there is a general decline in vital resources.
The 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. can have on him. In fact, the induction of the pharmacological coma temporarily reduces the activity of the nerve cells of the brain - in practice it is as if it put them to rest for a certain period of time - and this allows the tissues, which the aforementioned cells compose, to overcome difficulties and stress, deriving from the critical circumstances already mentioned several times.
In essence, therefore, the pharmacological coma is a remedy that doctors use to reduce the brain's needs, when such needs, due to a potentially lethal condition for the organism, would not be adequately met.
Drugs for drug coma induction reduce metabolism and oxygen demand by 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 patient's vital functions are monitored continuously by the medical staff (in this case by the anesthesiologist). This is a precautionary measure, which allows you to notice in time any problems, complications, deterioration in health, etc.
Furthermore, the individual concerned needs support for breathing, such as mechanical ventilation, and nutrition, such as the 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 the latter necessary affects the duration of the pharmacological coma: the more a circumstance is serious from the clinical point of view, the more hypothetical time it will take for the patient to recover, once brought to the pharmacological coma; vice versa, the causal circumstance is less serious and the hypothetical time spent in a pharmacological coma is shortened.
In light of the above, therefore, the duration of the pharmacological coma varies from patient to patient, depending on the causal circumstances (ie the motivations that convinced the doctors to resort to induced coma).
REHABILITATION
In the same way as people who come out of the pathological coma, people who awaken from the pharmacological coma need specific treatments, which serve to favor a return to a normal life.
The care in question includes:
- Physiotherapy, essential to remedy muscle contractions, resulting from prolonged immobility;
- Occupational therapy, whose field of application ranges from favoring the reintegration of the patient, in a social context, to adapting the home environment according to the needs of the person just awakened from the pharmacological coma;
- Psychotherapy, whose objective is to help the patient overcome the first stages of awakening from a profound state of unconsciousness and to make him accept that therapies are necessary, for a 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 pharmacological coma are at risk of hypotension .
To prevent the phenomenon of hypotension, in people in a pharmacological coma, doctors resort to administering medicines that raise blood pressure, in such a way as to keep the latter normal.
Just like people in pathological coma, individuals in a pharmacological coma run the risk of developing so-called immobilization complications, namely: aspiration pneumonia, pressure sores, thromboembolic disease, etc.
| Typical risks of pharmacological coma | Causes | Prevention |
Aspiration pneumonia |
|
|
Bedsores |
|
|
BARBITURIC AND RISK OF INFECTION
Some past research has advanced the hypothesis that the barbiturates in use to induce pharmacological coma determined a lowering of the immune defenses, with a consequent increase in the risk of infection.
Subsequent studies, however, have shown that no such strong evidence exists, in favor of the hypothesized consequential relationship between the use of barbiturates for pharmacological coma and greater risk of infection.
NIGHTMARKS AND HALLUCINATIONS
When they wake up, many people who undergo pharmacological coma tell of being victims of hallucinations and nightmares .
According to some experts, hallucinations and pharmacological coma nightmares would be due to attempts made by the brain of patients to perceive something (eg: sounds) from the surrounding environment.
Prognosis
Despite some criticisms against it, the pharmacological coma seems to be a solution of a certain value and capable of functioning.
However, it is important to emphasize 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 one hand the pharmacological coma can represent a possible source of benefit, on the other hand we must not forget that the hopes of recovery and survival of the patient are scarce. All this makes any prediction on the uncertain prognosis.
Criticisms
Some doctors have begun to doubt the usefulness of the pharmacological coma, since several groups of researchers have demonstrated the ineffectiveness of coma induced in circumstances such as: major neurosurgery interventions, cerebral edema due to head trauma, rupture of a brain aneurysm, ischemic stroke and status epilepticus.
It should be pointed out, however, that what was shown by the aforementioned research groups regarding pharmacological coma came from studies that were mostly isolated and in need of further study.
