3.3. EV Size and Concentration
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To test the EVs for size and concentration, a Nanoparticle Tracking Analysis (NTA) was performed. From the NTA measurements for the entire patient population, the average basal particle size was 113 ± 12.7 nm. Comparison of randomization groups revealed that the mean particle size initially increased in both groups after induction of anesthesia (Sevo: 120 ± 8.87 nm, Prop: 132 ± 11.5 nm) and decreased slightly after the 30 min surgery time (Sevo: 116 ± 12.7, Prop: 126 ± 10.6 nm), with a statistically significant difference between Sevo and Prop observed for both time points (anesthesia: In addition to size, anesthesia-related changes of particle concentration were of particular interest to uncover potential effects of anesthetics on EVs. For this purpose, particle concentrations were measured in the size range of 50 to 150 nm (ROI), corresponding to the expected exosomal size, to approximately differentiate EV subtypes. In the Sevoflurane group, there was initially a significant increase in particle concentration after induction of anesthesia and 30 min after incision (fc in anesthesia: 1.9 ± 0.7, 