TABLE 3.

Effect of oxygen therapy on the physiological traits

Phenotypic trait	Overall effects [n=36]				Responders [n=9] versus non-responders [n=26#]
	Sham	Oxygen therapy	Median change	p-value¶	Median change Within responders	Median change Within non-responders	p-value+
Loop gain, LGn [instability]	0.41 [0.38 to 0.49]	0.38 [0.33 to 0.45]	−0.05 [−0.11 to 0.01]	0.026	−0.10ƒ [−0.21 to −0.1]	−0.03 [−0.10 to 0.03]	0.16
Loop gain, LG1 [sensitivity]	0.63 [0.56 to 0.75]	0.46 [0.40 to 0.58]	−0.18 [−0.25 to −0.04]	<0.00001	−0.20* [−0.40 to −0.101	−0.17*** [−0.24 to −0.03]	0.4
Delay s	10.1 [8.9 to 11.4]	12.8 [10.0 to 15.4]	+2.0 [0.9 to 4.4]	<0.00001	+1.6* [0.6 to 2.3]	+2.4*** [0.9 to 5.3]	0.3
Arousal threshold %	131 [116 to 151]	118 [109 to 150]	−9.8 [−20 to 2]	0.038	−9.8* [−21.6 to −2.2]	−9.5 [−17.4 to 10.7]	0.3
Vpassive % [collapsibility§]	91.5 [75.0 to 94.2]	87.3 [69.7 to 94.8]	0.0 [−11.2 to 4.0]	0.7	+0.6 [−0.7 to 3.8]	−2.1 [−13.4 to 4.0]	0.6
Compensation %	0 [−11.8 to 6.8]	−1.9 [−22.5 to 5.8]	−3.2 [−13.1 to 11.9]	0.5	−4.7 [−11.5 to 1.7]	−1.6 [−16.8 to 12.8]	0.9

Data are presented as median (interquartile range).

^#: one non-responder provided no data; no 7-min windows of non-rapid eye movement sleep with no longer than 30 s of continuous wake were available for analysis;

^¶: Mann–Whitney U-test;

⁺: Wilcoxon signed-rank test;

^§: higher values of V_passive indicate less-severe collapsibility;

^ƒ: p<0.1;

^*: p<0.05;

^***: p<0.001 Wilcoxon signed-rank test within responder/non-responder subgroups.