Propofol and Remifentanil Effect-site Concentrations Estimated by Pharmacokinetic Simulation and Bispectral Index Monitoring During Craniotomy With Intraoperative Awakening for Brain Tumor Resection

Abstract

Different anesthetic techniques have been suggested for craniotomy with intraoperative awakening. We describe an asleep-awake-asleep technique with propofol and remifentanil infusions, with pharmacokinetic simulation to predict the effect-site concentrations and to modulate the infusion rates of both drugs, and bispectral index (BIS) monitoring. Five critical moments were defined: first loss of consciousness (LOC 1 ), first recovery of consciousness (ROC 1 ), final of neurologic testing (NT), second loss of consciousness (LOC 2 ), and second recovery of consciousness (ROC 2 ). At LOC 1 , predicted effect-site concentrations of propofol and remifentanil were, respectively, 3.6±1.2 μg/mL and 2.4±0.4 ηg/mL. At ROC 1 , predicted effect-site concentrations of propofol and remifentanil were, respectively, 2.1±0.3 μg/mL and 1.8±0.3 ηg/mL. At NT, predicted effect-site concentrations of propofol and remifentanil were, respectively, 0.9±0.3 μg/mL and 1.8±0.2 ηg/mL. At LOC 2 , predicted effect-site concentrations of propofol and remifentanil were, respectively, 2.1±0.2 μg/mL and 2.5±0.2 ηg/mL. At ROC 2 , predicted effect-site concentrations of propofol and remifentanil were, respectively, 1.2±0.5 μg/mL and 1.4±0.2 ηg/mL (data are mean±SE). A significative correlation was found between BIS and predicted effect-site concentrations of propofol (r 2 =0.547, P<0.001) and remifentanil (r 2 =0.533, P<0.001). Multiple regression analysis between BIS and propofol and remifentanil predicted effect-site concentrations at the different critical steps of the procedure was done and found also significative (r 2 =0.7341, P<0.001).

Recovery of psychomotor function after total intravenous anesthesia with remifentanil–propofol or fentanyl–propofol

“…However, the effect site concentration of propofol at the end of surgery in group R was significantly lower than that in group F. This result was consistent with previous studies [11,12]. One reason why recovery of psychomotor function was earlier in group R might be the lower effect site concentration of propofol compared with that in group F. Adequate analgesia can result in low effect site concentration of propofol with suitable BIS values [22].…”

Asleep-awake-asleep regimen for epilepsy surgery: a prospective study of target-controlled infusion versus manually controlled infusion technique

“…3). BIS values correlate significantly with the patient's level of consciousness [6,16,17], and objectively assesses not only the depth of general anesthesia but also sedation [18][19][20]. The return of BIS to the pre-induction values during the third phase appeared to indicate full recovery of consciousness, thereby allowing reliable language and motor response testing [21,22].…”

Perioperative Management and Anesthesia in Epilepsy

“…Cerrahi komplikasyonlar ise nöbetler, afazi, kanama, serebral ödem ve venöz hava embolisidir (Tablo 5) 74,81,82 .…”