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Purpose: To determine the plasma concentrations of propofol required to achieve different levels of sedation during monitored anesthesia care. Methods: Sixty ASA I-II, 18-65 yr-old patients, received a target-controlled continuous iv infusion of propofol. The target plasma concentration of propofol (CPt) was initially set at 0.4/Jg.ml -I. Two minutes after calculated equilibrium between plasma and effect-site concentrations, the CPt of propofol was increased by 0.2/~g.ml -~ steps until the patient showed no reaction to squeezing the trapezius. The level of sedation was assessed immediately before each increase in propofol Cpt using the Observer's Assessment of Alertness/Sedation (OAA/S) scale. Results: The CPt of propofol required to induce lethargic response to name was 1.3/Jg-ml -~ (5 ~ and 95 ~ percentiles: 1.0 -1.8/~g.ml-~), to obtain response after loud and repeated calling name was 1.7/~g-ml -~ (I .2 -2.2 /~g'ml-~), to obtain response after prodding or shaking was 2.0 ~g.ml -~ (I.6 -2.6/ag-ml-~), to obtain response after squeezing the trapezius was 2.4/Jg'ml -I (I.8 -3.0/Jg'ml-a). Patients showed no response after squeezing the trapezius at 2.8/ag.ml -I (2.0 -3.6 ~g-ml-~). Correlation between CPt propofol and sedation scores were r = 0.76, P < 0.0001. Conclusions: Target-controlled infusion of propofol provided easy and safe management of intraoperative sedation, allowing fast and predictable deepening in the level of sedation, while minimizing systemic side effects of intravenous sedation due to the minimal risk of overdosing the drug.Objectff : DEterminer les concentrations plasmatiques de propofol n&essaire pour fournir diffErents niveaux de sedation monitor&. M6thode : Soixante patients ASA I-II de 18-65 ans ont re~u une perfusion continue de propofol iv ?~ cible contr61&. La concentration plasmatique cibl& de propofol (Cpc) &ait d'abord de 0,4/lg.ml-'. Deux minutes aprEs avoir atteint I'Equilibre entre la concentration plasmatique et celle du site d'effet, la Cpc de propofol a 6tE augmentE par paliers de 0,2 pg.ml-'jusqu'~ ce que le patient ne rEagisse plus a une pression sur le trapeze, Le niveau de sedation a EtE EvaluE immEdiatement avant chaque augmentation de la Cpc de propofol fi I'aide de I'&helle de cotation de la vigilance par I'observateur/sEdation (CVO/S). R~sultats : La Cpc de propofol n&essaire pour induire une reaction IEthargique du patient ~. I'appel de son nom Etait de 1,3/Jg.ml-' (5 ~ et 95 ~ percentiles : 1,0 -1,8/Jg.ml-'), pour obtenir une reaction apt& I'appel du nom rEp&E et ~. voix forte &ait de 1,7/lg.ml-' (I,2 -2,2/~g'ml-~), pour rEagir fi une pouss& ou une secousse, 2.0 /Jg-ml -' ( 1.6 -2.6 ~g'ml-~), et pour rEagir a une pression sur le trapeze, 2,4/Jg'ml -~ ( 1,8 -3,0 pg.ml-'). Les patients n'ont pas rEagi ~ la pression sur le trapeze avec une concentration de 2,8/ag.ml-' (2,0 -3,6/~g.ml-'). La corrElation entre la Cpc de propofol et les niveaux de sedation a EtE aussi observ&, r = 0,76, P < 0,000 I. Conclusion : La perfusion de propofol ~ cible contr61& foumit une ligne de ...

We evaluated the use of target-controlled infusion of propofol to place extratracheal airways in this prospective, randomized study and demonstrated that the target plasma concentration of propofol required to successfully place a laryngeal mask in >95% of healthy, unpremedicated patients is 6 microg/mL, compared with 4 microg/mL to place a cuffed oropharyngeal airway.

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