[Neurological consequences after long-term sedation in the ICU]

Experiments performed in mammals, including non-human primates, have demonstrated an increase in neuronal death rates normally seen in normal brain development. Such an increase is encountered in diseases but also after exposure of the brain to various class of anaesthetics. In living animals, it can (but not always) result in persistent cognitive impairment. Most of the experiments have been conducted in animals which were never exposed to any pain, which questions their relevancy. On the clinical side, all data comes from retrospective studies. Given the multiple bias, they cannot definitely state that a protocol, if toxic, is more or less when compared to another. Until now, prospective follow-up of children exposed to anaesthetics in utero or during the first months of life do not suggest a major deleterious effect. Yet, a minor one, if existing, would be hard to detect among polluting variables (e.g. pathology requiring anaesthesia, long hospitalization after birth, preterm birth, environmental stress...). For sure, when surgery is mandatory during pregnancy, it is generally for maternal indication and should not be a motif strong enough for foetal extraction, especially in terms where the baby has few chances to survive. Second, it is known for years than anaesthesia before 1 year of age is much riskier than after 1 year, whatever the theorical neurotoxicity is. Third, this enforces the need to develop tools enhancing the precision of anaesthesia as much as possible. Meanwhile, when an infant has undergone numerous general anaesthesias, we strongly recommend a long-time neurological follow-up.