A new rapid method of Ion Mobility Spectrometry to measure blood propofol concentrations in patients during ERCP
Background and Goal of Study:  Due to the technical and methodological problems, none of the methods published so far is ready for clinical routine application. In this study, the new ion mobility spectrometer[1] (IMS, measurement within 1 minute without any pre-treatment) was used to directly quantify propofol in the whole blood. we used the new IMS to find the difference between the measured and predicted blood propofol concentrations during TCI in endoscopic retrograde cholangio pancreatography (ERCP). 

Materials and Methods:  We studied 28 patients scheduled for ERCP under total intravenous anesthesia using the Marsh model . Propofol was infused to achieve target effect compartment concentrations from 1.5 μg ml-1 to 3.5 μg ml-1 and remifentanil was kept at a constant speed of 2.5 μg kg-1 h-1. measured concentrations (Cm) were analysed by IMS and compared with concentrations predicted (Cp) displayed by the TCI system. Agreement between Cm and BIS was determined by regression analysis. 
Results and Discussion:  We found there was negative correlation in statistics between venous propofol concentrations and BIS (R=-0.456, P<0.001), while other previous researches showned no obvious relationship between artery propofol concentrations and BIS. The measured concentrations tended to be higher than predicted concentrations especially after stoping propofol infusion.

CONCLUSION:The new IMS could be applied to measure the propofol concentrations as a point-of-care mornitor in ERCP anesthesia.
Referrence:1. Wang X, Zhou Q, Jiang D, Gong Y, Li E, Li H. Ion mobility spectrometry as a simple and rapid method to measure the plasma propofol concentrations for intravenous anaesthesia monitoring.Sci Rep. 2016 Nov 21;6:37525

03 / A new rapid method of Ion Mobility Spectrometry to measure blood propofol concentrations in patients during ERCP