Length of Individual Apnea Events Is Increased by Supine Position and Modulated by Severity of Obstructive Sleep Apnea

Table 2

The individual event data, median (range). In mild, moderate, and severe OSA categories median values of apnea event durations, proportions of apnea events (of all respiratory events), and the maximum desaturation depths were significantly greater in supine position. Desaturation areas were significantly larger in supine position in patients with moderate and severe OSA. Hypopnea events were statistically significantly longer in nonsupine position in moderate OSA category.

Normal

Mild

Moderate

Severe

Supine position

Nonsupine position

p value

Supine position

Nonsupine position

p value

Supine position

Nonsupine position

p value

Supine position

Nonsupine position

p value

Patients ()

90

158

117

161

Hypopnea duration (s)

29.0; (12.5–68.0)

27.8; (15.0–127.7)

0.499

27.0; (13.8–56.3)

27.4; (11.0–74.5)

0.257

26.5; (16.0–42.0)

27.3; (13.0–61.0)

0.001

25.0; (13.0–54.0)

25.0; (12.3–63.0)

0.221

Apnea duration (s)

14.6; (10.1–28.5)

13.9; (10.0–43.9)

0.144

15.1; (10.1–55.6)

14.2; (10.0–51.0)

<0.001

18.0; (10.7–44.0)

16.0; (10.8–92.5)

<0.001

22.0; (10.5–52.2)

19.8; (11.0–64.3)

<0.001

Proportion of apnea events (%)

33.3; (3.8–92.0)

34.8; (5.3–80.0)

0.859

31.2; (1.0–97.8)

25.0; (1.2–94.7)

0.022

43.5; (1.3–97.7)

23.1; (1.3–91.2)

<0.001

43.5; (0.8–99.5)

24.1; (0.4–99.0)

<0.001

Desaturation duration (s)

25.9; (8.8–118.5)

23.3; (6.5–81.6)

0.220

26.6; (11.0–54.9)

27.4; (5.5–72.5)

0.324

27.0; (13.3–43.8)

27.5; (9.8–64.1)

0.570

27.3; (6.8–59.0)

27.5; (8.9–70.4)

0.347

Desaturation area (s%)

70.8; (23.5–337.0)

67.6; (15.0–245.3)

0.064

75.6; (29.5–240.0)

75.7; (24.5–187.1)

0.294

83.3; (39.4–345.5)

78.8; (24.0–184.8)

0.001

127.3; (35.3–795.3)

101.8; (22.9–807.5)

<0.001

Desaturation depth (%)

4; (4–18)

4; (4–12.5)

0.401

5; (4–13)

4; (4–8.5)

<0.001

5; (4–15)

4.5; (4–11.5)

<0.001

8; (4–36)

6; (4–33)

<0.001

Maximum desaturation depth (%)

7; (4–28)

6; (4–25)

0.014

10; (4–27)

8; (4–23)

<0.001

13; (5–33)

9; (4–40)

<0.001

23; (9–70)

20; (4–62)

<0.001

Number of hypopnea events

746

444

4696

2635

6281

3820

18033

19663

Number of apnea events

420

246

2735

915

6461

1530

16014

9441

Number of desaturation events

899

512

6039

3033

10731

4537

32512

27918

The patients were divided into OSA severity categories based on the total AHI. The statistical significance of differences between events occurring in supine and nonsupine positions was evaluated using the Wilcoxon signed rank test. was considered as the limit for statistical significance.