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.