Sleep disorders, drowsiness, fatigue …
The progress made in the field of anesthesia has made it possible to reduce the length of hospital stays, or even, for 3 out of 10 patients, to go home the same evening. However, many complain of side effects lasting several days to several months.
“We thought for a long time that the brain was totally asleep, but this is not the case,” explains Dr Laure Pain, anesthesiologist and researcher at Inserm. The anesthesia in fact creates a disconnection between the cortex, area of consciousness and reasoning, and the thalamus, a kind of crossroads, which notably redistributes sensory information. However, we now know that a secondary pathway is always reactive: the limbic system, the “primitive brain”, where the amygdala is located in particular, involved in learning, memory and the regulation of emotions. In short, if the information does not take the usual path, it arrives anyway, but without conscious perception. “
One in three patients
The symptoms observed after anesthesia are not anecdotal. Almost one in three patients suffers from sleep disturbances, episodes of unexplained sleepiness and fatigue, up to 5 days later. And this, whether the anesthesia lasted twenty minutes, for an examination without surgery such as a colonoscopy, or several hours. Consequence: a slower resumption of activities and possible accidents related to attention deficit.
Laure Pain’s team has just demonstrated that an anesthesia lasting thirty minutes, in rats, shifts the internal clock of the brain which controls the circadian rhythms by one hour (the alternation of sleep-wakefulness, the control of appetite, hormones …). By exposing patients to natural light immediately after the procedure, we could probably limit arrhythmias.
Memory impairment
Other work is being carried out on even more persistent side effects: memory and cognition disorders. Again, the duration of the anesthesia does not play a role. But the patient’s age is! One week after the anesthesia, 20% of over 30s but 50% of over 60s complain of repeated forgetfulness or intellectual disturbances, although they had no problem before. After three months, 20% of 60-69 year olds and 29% of over 70s are still embarrassed.
Stimulate memory and talk
These disorders are transient and reversible. But feeling the effects of anesthesia for 3 to 6 months, when you are 70 years old, it can have psychological consequences and lead to depressive states.
“To prevent these effects, you have to get your brain to ‘move’ as soon as possible. Especially if it is an elderly person: do not hesitate to ask her questions, to make her note the events, to encourage her to read … Anything that can stimulate her memory and her intellect is beneficial . For those most at risk, molecules developed against memory disorders could be used in prevention.
Nightmares, dark thoughts …
While some complain of forgetting, others suffer the consequences of what are called “memorization phenomena”. They keep memories of the anesthesia, but these are reinterpreted by the brain. This phenomenon remains rare. But it still concerns one to two people in a thousand, or about 20,000 cases per year. “Product fluctuations promote the perception of sounds, impressions, and especially emotions,” explains Dr. Laure Pain. A few years ago, the medical community responded to these complaints with denial. Today, we know that this is a very traumatic event, with psychological consequences: seven out of ten affected patients suffer from repeated nightmares or anxious reminiscence. Half of them even develop a real post-traumatic stress associating nightmares, anxiety, disorders of mood and behavior, even morbid ideas. Not to mention phobias, especially of the hospital, which can lead patients to escape the healthcare system. “
How to avoid these traumas?
“By explaining these phenomena and taking charge of them very early,” answers the specialist. This is what we are going to try to demonstrate in a study involving 18,000 patients in Strasbourg University Hospitals, private clinics and Beaujon Hospital in Paris. They will be followed when they wake up the following week, then six months later by a psychologist. In Australia, where this detection system exists, the results are very encouraging. “