Obstructive Sleep Apnea

With the exception of one patient whose BMI was 26.6 k^m2, all patients and control subjects were overweight, as each BMI value exceeded by at least 20 percent the normal median BMI value for men of medium body build. Anthropometric characteristics and PCSA measurements were similar in patients and control subjects (Table 1). Minimal PCSA was less in patients than in control subjects, but this difference was not significant. Patients had significantly higher AHI, AI, and Rp than control subjects.

There were no significant differences in PFTs between patients and control subjects (Table 2). Mean values for all tests were normal in both groups. All values for FEF50%/FIF50% were less than 1.0 and therefore considered normal, except in one patient whose FEF50%/FIF50% was 1.77. One control sub­ject and no patient with OSA had the sawtooth appearance of the flow-volume loop. Sawtooth oscilla­tions of the size and configuration reported by others were not observed in the middle or the end regions of the vital capacity in our subjects. Small oscillations of expiratory and inspiratory flow (<0.5 Us) were seen in the majority of patients and control subjects, but these were not limited to the midportion of the limbs of the flow-volume loop.

FIGURE 1. Relationship between

FICURE 1. Relationship between FEF50%/FIF50% and mean oropharyngeal cross-sectional area in patients with OSA (n = 14). When one subject (x) was eliminated from analysis, this relationship did not attain significance (rs= —0.43; p = 0.07).

Pharyngeal cross-sectional area was not significantly related to any measures of pulmonary function when all subjects were considered together. In patients with OSA, we found a significant inverse relationship between mean oropharyngeal cross-sectional area and FEF50%/FIF50% (rs=-0.54; p = 0.03; Fig 1). No such relationship was seen in the control group. This relationship remained significant when partial corre­lation analysis accounted for age and BMI. The patient with OSA who had the highest FEF50%/FIF50% (1.77) had the lowest mean oropharyngeal area (85 mm2). When these “outlier” values were dropped, the relationship of mean oropharyngeal cross-sectional area to FEF50%/FIF50% was not quite significant at the 0.05 level (rs= -0.43; p = 0.07). tadacip 20 mg

Table 1 —Anthropometric Characteristics, Sleep-Disordered Breathing Indices, Pharyngeal Size, and Resistance Data

Data

Patients

Controls

No.

Mean ± SE

Range

No.

Mean ± SE

Range

Anthropometric

15

10

Age, у

45.8 ±2.8

30-62

41.0±4.0

27-59

Weight, kg

109.6 ±5.7

80-159

103.3 ±4.6

90-135

BMI, kg/m2

35.6 ± 1.8

26.6-49.6

32.2 ± 1.5

27.9-42.3

Polysomnography

15

10

AHI, events per h

68.5 ±8.8*

25.4-160.0

0.7±0.2

0-2.6

AI, events per h

50.1 ±7.4*

11.7-118.3

0.5±0.2

0-2.0

Pharyngeal size

14

10

Minimal area, mm2

56± 15

0-187

92± 16

0-203

Mean area, mm2

186 ±26

82-380

186 ±14

116-271

Mean nasopharyngeal area, mm2

131 ±22

26-312

151 ±17

68-256

Mean oropharyngeal area, mm2

228 ±31

85-448

213 ±17

130-279

Pharyngeal resistance, cm H2 O/L/s

9

6.9±l.lt

2.5-12.4

8

3.7 ±0.6

0.7-5.6

Pharyngeal resistance in all subjects was signifi­cantly related only to the percentage of predicted values for midflow rate (FEF25-75%; rs=-0.56; p = 0.01). This association remained significant after adjustment for anthropometric variables. Pharyngeal resistance was not related to FRC. In all subjects the relationship between Rp and FEF50%/FIF50% ap­peared random (rs= -0.25; p = 0.34).

Table 2—Results of PFTs

Data

Patients

Controls

No. of subjects

15

10

FVC, percent predicted

94.5±3.6

104.0 ±3.3

FEV./FVC %

79.6 ±0.9

78.3 ± 1.7

FEF25-75%, percent predicted

91.6 ±4.7

96.8 ±7.8

PEF, percent predicted

121.5±6.0

127.5 ±3.8

PIF, IVst

7.1 ±0.4

8.8 ±0.6

FEF50%/FIF50%

0.74 ±0.08

0.62 ±0.06

MW, percent predicted

95.1 ±5.3

102.3 ±5.9

TLC, percent predicted

97.9 ±3.4

104.0 ±2.9

RY percent predicted

88.9 ±4.8

90.9 ±5.9

FRC, L

2.92 ±0.24

3.06 ±0.23

FRC, percent predicted

93.1 ±5.1

88.8±5.7

ERV, L

1.07 ±0.19

1.14 ±0.18

Inverse relationships existed between the frequency of apneas and hypopneas and several measures of pulmonary function (Table 3). The significance of all of these relationships was dependent upon BMI, but not age. No relationship between AHI (or AI) and FEF50%/FIF50% could be demonstrated. Pharyngeal resistance was significantly related to AI (rs = 0.50; p = 0.02) and AHI (rs = 0.51; p = 0.02) in all 17 subjects with Rp measurements. In patients with OSA, the AI was significantly related to percentage of predicted values for MW (rs= -0.77; p<0.01; Fig 2) and FRC (rs= —0.45; p<0.05). The former relationship was independent of anthropometric variables, while the latter was dependent on BMI, which was significantly related to both AI and FRC. In patients with OSA, the AHI was significantly related to FRC (rs= -0.74; p<0.01), but this association was also not significant when BMI was taken into account.

Table 3-Significant Correlations between PFTs and Sleep- Disordered Breathing in All Subjects

Data

rs

AI

AHI

FVC, percent predicted

-0.47t

— 0.461″

MW, percent predicted

-0.36f

NSt

TLC, percent predicted

— 0.37t

-0.431″

FRC, L

NS*

— 0.35t

PIF, Us

— 0.44t

-0.37f

FIGURE 2. Relationship betwee

FIGURE 2. Relationship between AI (mean number of apneas per hour of sleep) and percentage of predicted value for MW in patients with OSA (n = 15).