Effects of short-term hyperoxia on erythropoietin levels and microcirculation in critically Ill patients: a prospective observational pilot study

Table 4 Changes in nitrite/nitrate, GSH and ROS after a 2-hour exposure to hyperoxia and 2 h after return to baseline FiO₂

	t0	t1	t2	p (time)^a	p (interaction)^b
Nitrite/nitrate (μM)					0.378
Hyperoxia (n = 12)	41 ± 17	45 ± 21	43 ± 18	0.301
Controls (n = 12)	51 ± 18	55 ± 16	59 ± 14	0.198
GSH (μM)					-
Hyperoxia (n = 12)	2.21 [2.12–2.28]	2.17 [2.09–2.25]	2.24 [2.20–2.39]	0.114
Controls (n = 12)	2.19 [2.12–2.33]	2.18 [2.15–2.23]	2.23 [2.17–2.28]	0.273
ROS (RFU)					-
Hyperoxia (n = 12)	2915 [1196–6537]	3109 [1348–6961]	3061 [1261–5841]	0.046
Controls (n = 12)	1773 [1070–3018]	2024 [1135–3069]	1841 [1066–3058]	0.338

These analyses were restricted to the 12 patients per group. Data are expressed as mean ± standard deviation or median [1st-3rd quartile], as appropriate. (t0): baseline; (t1): 2 h 1.0 FiO2; (t2): 2 h after return to baseline FiO₂. RFU relative fluorescence units
^a Overall effect of time on the variance in each group. One-way ANOVA for repeated measures with Bonferroni’s post hoc test or Friedman test with Dunn’s test for multiple comparisons, as appropriate
^b Test of interaction between time and groups. Two-way ANOVA for repeated measures. This was applicable only to normally distributed variables

ISSN: 1471-2253