Table 3. Airway resistance, lung compliance, and mechanical ventilation-related parameters.
| Patients with airflow limitation (N = 98) | Patients without airflow limitation (N = 428) | p value | |
|---|---|---|---|
| Cst (mL/cmH2O) | 63.65 ± 15.9 | 59.81 ± 14.4 | 0.030 |
| Rfe (cmH2O L-1s-1) | 14.11 ± 7.69 | 6.49 ± 2.40 | < 0.001 |
| Rmv (cmH2O L-1s-1) | 10.67 ± 3.17 | 10.62 ± 2.65 | 0.88 |
| cRmv (cmH2O L-1s-1) | 7.69 ± 3.14 | 7.44 ± 2.60 | 0.48 |
| Ventilation mode | |||
| VCV | 77 (79%) | 318 (74%) | |
| PCV | 21 (21%) | 110 (26%) | |
| TV (mL) | 0.55 (0.48–0.61) | 0.52 (0.46–0.59) | 0.056 |
| TV/PBW (mL/kg) | 9.71 (8.64–11.52) | 9.58 (8.31–10.97) | 0.29 |
| Frequency (/min) | 10 (10–10) | 10 (10–10) | 0.30 |
| PIP (cmH2O) | 14.54 (12.79–16.47) | 14.25 (12.62–16.25) | 0.69 |
| Pplat (cmH2O) | 12.54 (10.61–14.13) | 12.27 (10.63–14.47) | 0.97 |
| Pinf (cmH2O) | 7.83 (5.27–9.34) | 7.44 (5.36–8.99) | 0.51 |
| PEEP (cmH2O) | 3.96 (1.84–5.02) | 3.22 (1.71–4.98) | 0.23 |
| Tube type | |||
| Normal, n (%) | 74 (76%) | 333 (78%) | |
| Spiral, n (%) | 24 (24%) | 95 (22%) | |
| Tube size (ID) | |||
| 6.5 mm, n (%) | 3 (3.1%) | 20 (4.7%) | |
| 7.0 mm, n (%) | 32 (33) | 219 (51%) | |
| 7.5 mm, n (%) | 35 (36) | 101 (24%) | |
| 8.0 mm, n (%) | 28 (29%) | 88 (21%) |
Data are presented as n (%), mean ± standard deviation, or median (interquartile range). Cst = static lung compliance. Rfe = airway resistance under forced expiration. Rmv = airway resistance under mechanical ventilation. cRmv = corrected airway resistance under mechanical ventilation. VCV = volume-controlled ventilation. PCV = pressure-controlled ventilation. TV = tidal volume. Pplat = plateau pressure. Pinf = the airway pressure that corresponds to an inflection point during the expiratory phase.
PEEP = positive end-expiratory pressure.