Measuring the depth of sedation (cf. ) – fractal and symbolic dynamics methods of EEG analysis give similar results as BIS method. In this case sedation has been employed to secure adequate comfort for 65-year-old male patient during long, unpleasant procedure (colonoscopy with polypectomy). Sedation has been controlled according to the BIS (target BIS value between 60 and 80) with intermittent boluses of propofol. At 16. and 27. minutes of the study sedation was lightened to level 3 in OAA/S score. Record showed that at those moments (D
- 1)*100 rose rapidly to rich the highest value. BIS increased only once (at 27. minute) while at 16. minute remained unchanged. Awakening can be predicted by rise of the (D
- 1)*100 towards its highest value. Exact dosage and timing of drugs administration are also shown.