Fig. 4From: Correlation of exhaled propofol with Narcotrend index and calculated propofol plasma levels in children undergoing surgery under total intravenous anesthesia - an observational studyScatter plots of exhaled propofol concentration in parts per billion (ppb) and propofol plasma concentration (μg·ml− 1) calculated by the Paedfusor model and Kataria model for induction (I) and maintenance (M) of anesthesia and emergence (E) from anesthesia (r = correlation coefficient)Back to article page