Table 2 Characteristics of patients according to their intraoperative median exhaled tidal volumes (VT) (mL/kg PBW).
Median VT subgroups (mL/kg PBW)a | ||||
|---|---|---|---|---|
< 8 | 8-10 | > 10 | p value | |
Number, n(%) | 154(29.5%) | 200(38.3%) | 75(14.4%) | |
Age (years), Mean ± SD | 59.6 ± 14.1 | 57.4 ± 15.1 | 56.9 ± 15.6 | 0.298 |
Gender distribution | ≤ 0.001 | |||
Male, n(%) | 124(80.5%) | 141(70.5%) | 28(37.7%) * | |
Female, n(%) | 30(19.5%) | 59(29.5%) | 47(62.7%) * | |
Height (cm), Mean ± SD | 177.9 ± 9.7 | 173.7 ± 9.7 | 161.4 ± 11.0 * | ≤ 0.001 |
Weight (kg), Mean ± SD | 84.1 ± 20.2 | 86.3 ± 21.3 | 89.6 ± 25.9 | 0.207 |
Predicted Body Weight (PBW)(kg), Mean ± SD | 72.9 ± 9.9 | 68.4 ± 10.2 | 55.7 ± 10.8 * | ≤ 0.001 |
Body Mass Index (BMI), Mean ± SD | 26.5 ± 5.4 | 28.4 ± 5.4 | 34.1 ± 8.9 * | ≤ 0.001 |
ASA classification | 0.884 | |||
1, n(%) | 6(3.9%) | 12(6.0%) | 3(4.0%) | |
2, n(%) | 61(39.6%) | 79(39.5%) | 29(38.7%) | |
3, n(%) | 73(47.4%) | 86(43.0%) | 35(46.7%) | |
4, n(%) | 6(3.9%) | 5(2.5%) | 2(2.6%) | |
Unclassified, n(%) | 8(5.2%) | 18(9.0%) | 6(8.0%) | |
Comorbidities | ||||
COPD, n(%) | 12(7.8%) | 16(8.0%) | 2(2.7%) | 0.270 |
Asthma, n(%) | 10(6.5%) | 14(7.0%) | 6(8.0%) | 0.916 |
Obstructive Sleep Apnea, n(%) | 18(11.7%) | 32(16.0%) | 13(17.3%) | 0.407 |
Oxygen dependency, n(%) | 8(5.2%) | 7(3.5%) | 3(4.0%) | 0.730 |
Obesity (BMI ≥ 30), n(%) | 33(22.6%) | 64(33.2%) | 50(68.5%) * | ≤ 0.001 |
Congestive Heart Failure, n(%) | 2(1.3%) | 11(5.5%) | 1(1.3%) | 0.051 |
Cancer, n(%) | 106(68.8%) | 124(62.0%) | 46(61.3%) | 0.681 |
Intraoperative ventilatory management | ||||
Minute ventilation (L/min), Mean ± SD | 75.9 ± 14.2 | 88.5 ± 13.8 | 108.7 ± 21.5 * | ≤ 0.001 |
Respiratory rate (breath/min), Mean ± SD | 10.6 ± 1.9 | 10.0 ± 1.6 | 9.6 ± 1.6 * | ≤ 0.001 |
Peak pressure (cmH2O), Mean ± SD | 20.9 ± 6.3 | 22.2 ± 5.6 | 23.6 ± 6.6 * | 0.004 |
PEEP (cmH2O), Mean ± SD | 3.7 ± 1.9 | 3.8 ± 2.3 | 3.9 ± 1.9 | 0.819 |
End-tidal CO2 (mmHg), Mean ± SD | 35.4 ± 4.2 | 34.3 ± 2.6 | 33.9 ± 2.7 * | 0.004 |
Mean FiO2, Mean ± SD | 70.2 ± 27.2 | 70.6 ± 26.6 | 74.0 ± 25.2 | 0.699 |
PaO2/FiO2 ratio, Mean ± SD | 298.9 ± 188.2 | 315.2 ± 249.4 | 248.1 ± 157.5 | 0.196 |
Intraoperative use of vasopressors, n(%) | 25(16.2%) | 28(14.0%) | 13(17.3%) | 0.741 |
Intraoperative fluid management | ||||
Infused crystalloids (mL/kg/h), Mean ± SD | 7.8 ± 3.2 | 8.3 ± 3.6 | 8.6 ± 3.7 | 0.213 |
Infused colloids (mL/kg/h), Mean ± SD | 1.8 ± 1.2 | 1.8 ± 1.6 | 1.4 ± 0.9 | 0.656 |
Estimated blood loss (mL), Mean ± SD | 650.6 ± 661.3 | 749.6 ± 802.5 | 869.1 ± 887.8 | 0.127 |
Fluid balance (evaporation & insensible losses not included) (mL/kg/h), Mean ± SD | 6.5 ± 3.3 | 7.1 ± 3.6 | 7.7 ± 4.1 | 0.079 |
Use of blood products, n(%) | 27(17.5%) | 55(27.5%) | 27(36.0%) * | 0.007 |
Duration of surgical procedure (minutes), Mean ± SD | 340.8 ± 92.2 | 345.6 ± 94.4 | 366.0 ± 98.7 | 0.155 |
Outcomes | ||||
POMV and ICU admission, n(%) | 17(11.0%) | 27(13.5%) | 18(24.0%) * | 0.028 |
POMV duration (days), Mean ± SDb | 1.5 ± 2.8 | 1.9 ± 3.8 | 2.1 ± 3.7 | 0.801 |
ICU LOS (days), Mean ± SDb | 3.3 ± 3.2 | 4.8 ± 6.4 | 3.7 ± 6.6 | 0.488 |
Hospital LOS (days), Mean ± SD | 6.2 ± 6.1 | 7.0 ± 6.6 | 8.3 ± 7.8 * | 0.101 |
In-hospital mortality, n(%) | 3(1.9%) | 2(1.0%) | 1(1.3%) | 0.752 |