Table 4. Changes of plasma profiles between paired samples.

	First Sample a Mean (95% CI)	Second Sample b Mean (95%CI)	P c
Control (all samples, n = 63)
PI3	73.1 (58.9–90.7)	76.9 (63.4–93.3)	0.335
SLPI	133.6 (118.8–150.1)	119.7 (106.8–134.2)	0.019
HNE	421.8 (351.5–506.1)	329.8 (276–394.1)	0.003
HNE/PI3 ratio	5.8 (4.4–7.6)	4.3 (3.3–5.5)	0.001
Control (pulmonary injury, n = 30)
PI3	88.2 (62.3–124.7)	81.6 (58.4–113.9)	0.302
SLPI	147 (125.4–172.2)	133.9 (115.4–155.4)	0.164
HNE	351.8 (268.6–460.7)	262.7 (202.5–340.9)	0.023
HNE/PI3 ratio	4.0 (2.6–6.2)	3.2 (2.1–4.9)	0.115
Control (extrapulmonary injury, n = 33)
PI3	61.6 (47–80.7)	73 (58.1–91.6)	0.023
SLPI	122.4 (103–145.5)	108.1 (91.1–128.3)	0.063
HNE	497.4 (388.8–636.5)	405.6 (321.1–512.4)	0.069
HNE/PI3 ratio	8.1 (5.8–11.3)	5.6 (4.1–7.5)	0.004
ARDS (all samples, n = 24)
PI3	48.9 (31.4–76)	57.5 (38.9–85.1)	0.132
SLPI	122.1 (101.3–147.1)	130.5 (104–163.9)	0.226
HNE	561 (414.4–759.4)	522.5 (421.3–648)	0.552
HNE/PI3 ratio	11.5 (7.7–17)	9.1 (6.1–13.6)	0.083

PI3, neutrophil elastase inhibitor (elafin); SLPI, secretory leukocyte proteinase inhibitor; HNE, neutrophil elastase; the plasma levels of PI3, SLPI, and HNE were shown in unit of ng/ml; 95%CI, 95% confidence interval.

^a. For at-risk control patients, the first plasma samples were collected within 48-hour of ICU admission; For ARDS patients, the first plasma samples were collected within 48-hour of ARDS diagnosis.

^b. The second samples were collected three days after the first collection.

^c. Paired t-test