Propofol Pharmacodynamics and Bispectral Index During Key Moments of Awake Craniotomy

Background: During awake craniotomy, the patient's language centers are identified by neurological testing requiring a fully awake and cooperative patient. Hence, anesthesia aims for an unconscious patient at the beginning and end of surgery but an awake and responsive patient in between. We investigated the plasma (Cplasma) and effect-site (Ceffect-site) propofol concentration as well as the related Bispectral Index (BIS) required for intraoperative return of consciousness and begin of neurological testing. Materials and Methods: In 13 patients, arterial Cplasma were measured by high-pressure liquid chromatography and Ceffect-site was estimated based on the Marsh and Schnider pharmacokinetic/dynamic (pk/pd) models. The BIS, Cplasma and Ceffect-site were compared during the intraoperative awakening period at designated time points such as return of consciousness and start of the Boston Naming Test (neurological test). Results: Return of consciousness occurred at a BIS of 77±7 (mean±SD) and a measured Cplasma of 1.2±0.4 μg/mL. The Marsh model predicted a significantly (P

http://ift.tt/2yPre5d