Loss of consciousness with intravenous induction of general anesthesia with remifentanil and propofol and its relationship with C-reactive protein

Abstract

Background and Goal of Study: Some published data suggested that inflammation and C-Reactive Protein (CRP) plasmatic concentration might be related with cognitive impairment after cardiac surgery 1 . We hypothesized that anesthetic needs for loss of consciousness (LOC) are influenced by a pre-operative inflammatory state. Materials and Methods: We studied 78 patients, 36 female, age between 21 and 81 years old, ASA I-IV, Glasgow Coma Score 14-15, submitted to brain and non-brain surgery. Anesthetic management for induction of general anesthesia was the same: using RugloopII® software, anesthesia started with TCI of remifentanil with an effect-site target concentration of 2.5 ng/ml and a constant infusion of 1% propofol at 200 ml/hr until LOC; for each patient, predicted effect-site concentration of propofol at LOC was registered. Pre-operative plasmatic concentration of CRP was determined, but until LOC anesthesiologists in charge was blind for that value.Quadratic regression was done to correlate pre-operative plasmatic concentration of CRP and predicted effect-site concentration of propofol at LOC; p Ͻ 0.05 was considered significant. Results: Pre-operative plasmatic concentration of CRP and predicted effectsite concentration of propofol at LOC showed an inverse correlation (r ϭ 0,79, p Ͻ 0.01) (Figure 1). Similar correlations were found when patients were divided into brain surgery group(r ϭ 0,64, p Ͻ 0.01) and non-brain surgery group (r ϭ 0,86, p Ͻ 0.01).