Fig. 4. Comparison of Narcotrend® and Bispectral Index® (BIS®). Scatter plot and linear regression line (Narcotrend®= BIS × (−0.149) + 16.478; BIS = Narcotrend®× (−5.397) + 99.318). Shown are all data pairs from awake through extubation (n = 350). The cluster of points well off the regression line, with BIS® values greater than 80 and Narcotrend® values between C2 and E0 are due to data pairs during induction of anesthesia. Narcotrend® was associated with a faster decrease than BIS®.