Table 4. Comparison of expiration-to-inspiration ratios (E/I ratios) of breath sound sound pressure for the right middle lobe between controls and atelectatic subjects.
| Frequency band | E/I ratio (dB) | P value | ||||
|---|---|---|---|---|---|---|
| Controls | Atelectasis subjects | Controls vs. Atelectasis | Atelectasis | |||
| Before treatment | After resolution | Before | After | Before vs. After | ||
| 100–200Hz | -6.6 (2.0) | - 4.8 (2.1) | - 6.5 (3.2) | 0.03 | 0.91 | 0.01 |
| 200–400Hz | -11.9 (2.9) | - 9.0 (3.6) | -12.1 (2.4) | 0.02 | 0.84 | 0.007 |
| 400–800Hz | -13.5 (2.6) | - 9.5 (3.7) | -11.0 (3.7) | 0.01 | 0.06 | 0.001 |
E/I ratio: expiratory breath sound sound pressure (dB)–inspiratory breath sound sound pressure (dB). Mean (SD) values are presented. Student’s unpaired t-test was used to test the difference between controls and atelectasis subjects, and paired t-test was used to test the difference between before and after treatment.