title: Bispectral index score and observer's assessment of awareness/sedation score may manifest divergence during onset of sedation: Study with midazolam and propofol.
abstract: BACKGROUND
  Correlation between the clinical and electroencephalogram-based monitoring has been documented sporadically during the onset of sedation. Propofol and midazolam have been studied individually using the observer's assessment of awareness/sedation (OAA/S) score and Bispectral index score (BIS). The present study was designed to compare the time to onset of sedation for propofol and midazolam using both BIS and OAA/S scores, and to find out any correlation.
  
  
  METHODS
  A total of 46 patients (18-60 years, either sex, American Society of Anesthesiologists (ASA) I/II) posted for infraumbilical surgeries under spinal anaesthesia were randomly allocated to receive either injection propofol 1 mg/kg bolus followed by infusion 3 mg/kg/h (Group P, n=23) or injection midazolam 0.05 mg/kg bolus followed by infusion 0.06 mg/kg/h (Group M, n=23). Spinal anaesthesia was given with 2.5 ml to 3.0 ml of 0.5% bupivacaine heavy. When sensory block reached T6 level, sedation was initiated. The time to reach BIS score 70 and time to achieve OAA/S score 3 from the start of study drug were noted. OAA/S score at BIS score 70 was noted. Data from 43 patients were analyzed using SPSS 12 for Windows.
  
  
  RESULTS
  Time to reach BIS score 70 using propofol was significantly lower than using the midazolam (P<0.05). Time to achieve OAA/S score 3 using propofol was comparable with midazolam (P=0.358).
  
  
  CONCLUSIONS
  A divergence exists between the time to reach BIS score 70 and time to achieve OAA/S score 3 using midazolam, compared with propofol, during the onset of sedation.
authors.affiliation: Department of Anaesthesiology, North Bengal Medical College, Sushrutanagar, Darjeeling, West Bengal, India.
authors.forename: Dipanjan
authors.initials: D
authors.lastname: Bagchi
authors.forename: Mohan Chandra
authors.initials: MC
authors.lastname: Mandal
authors.forename: Sabyasachi
authors.initials: S
authors.lastname: Das
authors.forename: Sekhar Ranjan
authors.initials: SR
authors.lastname: Basu
authors.forename: Susanta
authors.initials: S
authors.lastname: Sarkar
authors.forename: Jyotirmoy
authors.initials: J
authors.lastname: Das
keywords: Bispectral index score; midazolam; observer's assessment of awareness/sedation score; propofol; sedation