Table 2.
Comparison between tidal volume, oxygen saturation, dynamic compliance, and airway resistance at two different levels of apico-diaphragmatic ratio
| RR < 20 breaths/minute (15 ± 3) | RR > 20 breaths/minute (26 ± 5) | |||||
|
ADR < 2 (n = 23) |
ADR > 2 (n = 14) |
P value |
ADR < 2 (n = 17) |
ADR > 2 (n = 23) |
P value | |
|
Tidal volume (ml) |
577 ± 91 | 528 ± 101 | NS | 479 ± 109 | 483 ± 135 | NS |
|
Oxygen saturation (%) |
97 ± 3 | 97 ± 3 | NS | 97 ± 3 | 98 ± 2 | NS |
|
Compliance (mL/mbar) |
60 ± 25 | 42 ± 12 | 0.058 | 51 ± 25 | 48 ± 20 | NS |
|
Resistance (mbar L/second) |
15 ± 4 | 18 ± 7 | NS | 15 ± 3 | 16 ± 5 | NS |
Apico-diaphragmatic ratio (ADR) was defined as the ratio between the lung sound distribution in the apical lung areas (upper right (UR) + upper left (UL)) and the diaphragmatic lung areas (lower right (LR) + lower left (LL)) (ADR = (UL + UR)/(LL + LR)). Distribution was considered more heterogeneous if difference was larger than two, threshold derived from experience with healthy patients in supine position. P values are indicated (Wilcoxon two sample test) as well as non-significant (NS) data. RR = respiratory rate.