Clinical ReportClinical Variables Related to Propofol Effect-Site Concentrations at Recovery of Consciousness After Neurosurgical ProceduresNunes, Catarina S PhD*†; Ferreira, David A MVD*; Antunes, Luís PhD*; Amorim, Pedro MD‡Author Information From the *CECAV, Universidade de Trás-os-Montes de Alto Douro, Vila-Real, Portugal; †Departamento de Matemática Aplicada, Faculdade de Ciências, Universidade do Porto, Portugal; ‡Serviço de Anestesiologia, Hospital Geral de Santo António, Porto, Portugal. Received for publication January 4, 2005; accepted March 9, 2005. The authors wish to acknowledge the Portuguese Foundation for Science and Technology (Lisbon, Portugal) for their financial support under project POSI/EEA-SRI/57607/2004. Reprints: Dr. Catarina S. Nunes, Departamento de Matemática Aplicada, Faculdade de Ciências da Universidade Porto, Rua do Campo Alegre 687, 4169-007 Porto, Portugal (e-mail: [email protected]). Journal of Neurosurgical Anesthesiology: April 2005 - Volume 17 - Issue 2 - p 110-114 doi: 10.1097/01.ana.0000163198.02742.9d Buy Metrics Abstract Target controlled infusion (TCI) systems and computer data acquisition software are increasingly used in anesthesia. It was hypothesized that the use of such systems might allow retrieval of information useful to anticipate the effect-site concentrations of propofol at which patients would recover from anesthesia. The goal of the study was to identify variables related to propofol effect-site concentrations at recovery of consciousness (ROC). Sixteen patients with a Glasgow of 15, ASA 1 or 2, subjected to neurosurgical procedures, received TIVA with TCI propofol and remifentanil. Data were collected every 5 seconds from Datex AS3 and Aspect A200XP (BIS). Effect-site TCI was used for propofol (initial effect target 5.0 μg/ml) and for remifentanil (initial plasma target 2.5 ng/ml). All clinical events were noted. Variables possibly related to propofol effect-site concentration at ROC were selected. Data are expressed as mean ± SD. Effect-site propofol concentration at ROC was 1.3 ± 0.5 μg/ml. A positive correlation was found between propofol effect-site concentration at ROC and: age (49.3 ± 17 years) (P = 0.003); mean remifentanil dose during surgery (0.11 ± 0.05 μg/kg/min) (P = 0.003); mean propofol dose during surgery (0.12 ± 0.03 mg/kg/min) (P = 0.046); and remifentanil effect-site concentration at ROC (2.85 ± 2.06 ng/ml) (P = 0.002). Propofol effect-site concentrations were not correlated with: weight, height, LBM, duration of anesthesia, minimum BIS at induction (30.4 ± 6.8), time till minimum BIS (4.7 ± 2.2 min), mean and median BIS during surgery (38.2 ± 4.5 and 37.8 ± 5.3). BIS-related variables were not useful as ROC predictors. Only drug variables and age correlated with propofol effect-site concentrations at ROC. © 2005 Lippincott Williams & Wilkins, Inc.