Fig. 2

Acylcarnitine profiles distinguish Class 1 and Class 2 ARDS groups. Serum levels of short and medium-chain acylcarnitines are shown. Relative amounts (peak area ratio of analyte/internal standard) of metabolites shown were determined using stable isotope dilution liquid chromatography-high resolution mass spectrometry (LC-HRMS). Controls (n = 42) are shown as black circles, Class 1 (n = 44) as blue squares, and Class 2 (n = 43) as red triangles with black bars representing medians. Panels show relative levels for (a) propionylcarnitine, (b) butyrylcarnitine, (c) isovalerylcarnitine, and (d) octanoylcarnitine. Group comparisons were performed using the Kruskal–Wallis test. Asterisks indicate P < 0.05 (*), P < 0.01 (**), P < 0.001 (***), P < 0.0001 (****), and ns (not significant)