RESUMO
Alpha 2 agonists are appreciated drugs designed for the peri-operative period, because of their anxiolytic, sedative and analgesic properties. However, they are usually avoided during scoliosis surgery, a longlasting major procedure involving healthy patients, because of their potential effects on Somatosensory and Motorevoked potentials. The absence ofrecommendations suggests that their effects on evoked potentials are still unclear. Thus, we tried in this narrative review to identify the literature representative of the effects of clonidine and dexmedetomidine on evoked potentials, on human beings, published between 1988 and 2015 in English or French, using GOOGLE SCHOLAR and PUBMED. Paucity of literature prevented any conclusion about Clonidine's effects on evoked potentials, but no data suggested a noxious effect of Clonidine on evoked potentials, used in oral premedication (300 µg) or during the procedure (2 to 5 µg/kg). If literature was more extensive for dexmedetomidine, studies were still controversial. Although the majority of the studies did not find statistically significant differences concerning the effects of this drug on evoked potentials (loading dose of 0.3 to 1 µg/ kg followed by continuous infusion of 0.3 to 0.8 µg/kg/h), 2 case reports and 2 studies described substantial decreases. However, dexmedetomidine's shorter duration of action allowed a quick return to basal situation within an hour. In conclusion, more studies are needed in order to evaluate the effects of alpha 2 agonists on evoked potentials and to assess the safety of their use in this setting.