Table 3.
Intraoperative ventilation characteristics
| All patients | Low risk of PPCs | Increased risk of PPCs | P | |
| Ventilation mode | ||||
| Volume control | 70.1 (6816/9717) | 69.0 (4589/6649) | 72.7 (1910/2629) | <0.001 |
| Pressure control | 16.2 (1571/9717) | 17.5 (1161/6649) | 13.6 (358/2629) | |
| Pressure support or spontaneous | 1.1 (104/9717) | 1.3 (87/6649) | 0.6 (16/2629) | |
| Othera | 12.6 (1226/9717) | 12.2 (812/6649) | 13.1 (345/2629) | |
| Airway type | ||||
| Endotracheal tube | 81.8 (8064/9857) | 77.0 (5194/6742) | 95.5 (2550/2670) | <0.001 |
| Nasotracheal tube | 1.3 (127/9857) | 1.4 (97/6742) | 0.8 (21/2670) | |
| Supraglottic device | 15.9 (1570/9857) | 20.6 (1386/6742) | 2.7 (72/2670) | |
| Other | 1.0 (96/9857) | 1.0 (65/6742) | 1.0 (27/2670) | |
| Tidal volumes (ml) | 500.0 [455.0 to 558.5] | 500.0 [454.0 to 553.0] | 500.0 [460.0 to 562.5] | 0.017 |
| Tidal volumes ml kg−1 PBW | 8.1 [7.2 to 9.1] | 8.1 [7.2 to 9.1] | 8.2 [7.4 to 9.2] | 0.001 |
| Tidal volumes ml kg−1 ABW | 6.7 [5.8 to 7.7] | 6.7 [5.8 to 7.7] | 6.7 [5.8 to 7.6] | 0.354 |
| PEEP (cmH2O) | 3.5 [0.0 to 5.0] | 3.0 [0.0 to 5.0] | 4.5 [2.0 to 5.0] | <0.001 |
| Respiratory rate (bpm) | 12.0 [12.0 to 13.0] | 12.0 [12.0 to 13.0] | 12.0 [12.0 to 13.0] | 0.205 |
| Minute ventilation (ml min−1) | 6000 [5000 to 6769] | 6000 [5185 to 6816] | 6000 [4979 to 6870] | 0.003 |
| Ppeak (cmH2O) | 17.5 [15.0 to 21.0] | 17.0 [14.5 to 20.0] | 19.0 [16.0 to 22.0] | <0.001 |
| Pplat (cmH2O) | 15.5 [13.0 to 18.5] | 15.0 [13.0 to 18.0] | 17.0 [14.0 to 20.0]) | <0.001 |
| Driving pressure (cmH2O) | 12.0 [10.0 to 15.0] | 12.0 [10.0 to 15.0] | 13.0 [10.0 to 16.0] | <0.001 |
| Cdyn (ml cm−1 H2O) | 34.8 [28.1 to 42.8] | 35.4 [28.6 to 43.5] | 33.5 [27.1 to 41.1] | <0.001 |
| Cq.stat. (ml cm−1 H2O) | 41.7 [33.4 to 51.4] | 42.3 [34.3 to 52.0] | 40.0 [32.0 to 50.0] | <0.001 |
| Recruitment manoeuvre performed | 9.8 (965/9813) | 8.5 (570/6719) | 12.9 (343/2656) | <0.001 |
| FiO2 | 0.52 [0.45 to 0.70] | 0.54 [0.47 to 0.72] | 0.50 [0.45 to 0.60] | <0.001 |
| <0.40 | 7.1 (699/9808) | 6.5 (440/6727) | 9.0 (240/2660) | <0.001 |
| ≥0.40 to <0.60 | 51.7 (5068/9808) | 48.9 (3288/6727) | 60.5 (1609/2660) | |
| ≥0.60 to <0.80 | 29.5 (2895/9808) | 32.0 (2156/6727) | 22.5 (599/2660) | |
| ≥0.80 | 11.7 (1146/9808) | 12.5 (843/6727) | 8.0 (212/2660) | |
| SpO2% | 99.0 [98.0 to 100.0] | 99.0 [98.0 to 100.0] | 99.0 [98.0 to 100.0] | 0.198 |
| ≥96 | 97.6 (9583/9817) | 97.8 (6571/6721) | 97.0 (2573/2652) | 0.040 |
| >90 to <96 | 2.3 (222/9817) | 2.1 (140/6721) | 2.9 (77/2652) | |
| ≤90 | 0.1 (12/9817) | 0.1 (10/6721) | 0.1 (2/2652) | |
| EtCO2-kPa | 4.5 [4.1 to 4.9] | 4.5 [4.1 to 4.9] | 4.4 [4.0 to 4.8] | <0.001 |
Low versus increased risk of PPCs, according to the Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) risk score (<26 versus ≥26, respectively).
Data are presented as median [LQ to UQ] or % (CI); χ2 for categorical variables and Mann-Whitney for continuous variables.
aOther (e.g. high frequency oscillatory ventilation, jet ventilation, synchronised intermittent mandatory ventilation (SIMV). ABW, actual body weight; PBW, predicted body weight, calculated as: 50 + (0.91 × (cm height – 152.4)) for males and 45.5 + [0.91 × (cm height − 152.4)] for females; Cdyn, calculated dynamic respiratory compliance, calculated as [tidal volume/(Ppeak − PEEP)]; Cq.stat, static respiratory compliance; FiO2, fractional inspired oxygen; LQ, lower quartile; UQ, upper quartile; n, number with characteristic; N, number in group or subgroup; Ppeak, peak pressure; Pplat, Plateau pressure; PEEP, positive end-expiratory pressure; SpO2, peripheral oxygen saturation; EtCO2, expiratory carbon dioxide.