Table 2.

In vitro estimated concentrations using the extrapolation to zero-flow methodology against true concentrations.

	Estimated concentration	Measured concentration	p value
Glucose (mmol/L)	1.97 (1.59–2.19)	2.06 (1.93–2.25)	0.16
Lactate (mmol/L)	2.01 (1.71–2.44)	2.15 (2.05–2.37)	0.09
Pyruvate (µmol/L)	106.7 (87.3–143.9)	119.5 (108.5–127.5)	0.38
Glycerol (µmol/L)	242.1 (160.6–284.5)	231.6 (200.1–295.0)	0.11

In these experiments, seven catheters were used. Data summarized correspond to the data for each metabolite in all experiments. Data are expressed as median (min–max). Comparisons between estimated and measured concentrations were made using the Wilcoxon test for paired samples; no statistically significant differences were observed.