Table 1.
Patient characteristics and demographics for the full study cohort population and the matched study population
| Full Study Cohort Population | Matched Population | |||||||
|---|---|---|---|---|---|---|---|---|
| No Protective Ventilation (N = 2,844) |
Protective Ventilation (N = 388) |
Absolute Standardized Difference (%) |
P- Value |
No Protective Ventilation (N = 381) |
Protective Ventilation (N = 381) |
Absolute Standardized Difference (%) |
P- Value |
|
| Demographics | ||||||||
| Age | 62.6(12.4) | 62(13.6) | 5.2 | 0.351 | 61.6(13.8) | 62.3(13.3) | 5 | 0.491 |
| Female Sex | 1,577 (55.5) | 138 (35.6) | 40.7 | <0.001 | 140 (36.8) | 136 (35.7) | 2.2 | 0.763 |
| Body Mass Index | 28.5(6.5) | 27.6(6.8) | 13.2 | 0.014 | 28(5.7) | 27.6(6.7) | 6.7 | 0.354 |
| ASA Class 3 or higher | 2,217 (78.0) | 308 (79.4) | 3.5 | 0.523 | 307 (80.6) | 301 (79.0) | 3.9 | 0.589 |
| Comorbidities | ||||||||
| COPD | 671 (23.6) | 90 (23.2) | 1 | 0.857 | 90 (23.6) | 88 (23.1) | 1.2 | 0.862 |
| Congestive Heart Failure* | 81 (4.7) | 22 (7.1) | 10.2 | 0.121 | 16 (5.1) | 19 (6.3) | 4.8 | 0.548 |
| Coronary Artery Disease | 427 (15.0) | 67 (17.3) | 6.1 | 0.247 | 66 (17.3) | 66 (17.3) | 0 | 0.999 |
| Cerebrovascular History | 5.9 | 0.304 | 5.8 | 0.421 | ||||
| Transient ischemic attack | 74 (2.6) | 12 (3.1) | 12 (3.2) | 12 (3.2) | ||||
| Cerebrovascular accident | 65 (2.3) | 12 (3.1) | 8 (2.1) | 12 (3.2) | ||||
| Diabetes | 449 (15.8) | 60 (15.5) | 0.9 | 0.870 | 57 (15.0) | 60 (15.8) | 2.2 | 0.763 |
| Dialysis | 14 (0.5) | 3 (0.8) | 3.5 | 0.545 | 3 (0.8) | 3 (0.8) | 0 | 0.999 |
| Hypertension | 1,547 (54.4) | 193 (49.7) | 9.3 | 0.085 | 213 (55.9) | 191 (50.1) | 11.6 | 0.111 |
| Peripheral Vascular Disease* | 101 (5.8) | 14 (4.5) | 6 | 0.309 | 19 (6.1) | 14 (4.6) | 6.6 | 0.413 |
| Prior Cardiothoracic Surgery | 420 (14.8) | 66 (17.0) | 6.1 | 0.247 | 61 (16.0) | 64 (16.8) | 2.1 | 0.770 |
| Pulmonary Hypertension | 24 (0.8) | 5 (1.3) | 22.2 | <0.001 | 0 (0.0) | 4 (1.1) | 2.6 | N/A |
| Smoking | 8.9 | 0.100 | 4.8 | 0.506 | ||||
| Never Smoked | 757 (26.6) | 115 (29.6) | 118 (31.0) | 111 (29.1) | ||||
| Past Smoker (>1 month) | 1,565 (55.0) | 213 (54.9) | 209 (54.9) | 211 (55.4) | ||||
| Current Smoker | 522 (18.4) | 60 (15.5) | 54 (14.2) | 59 (15.5) | ||||
| Major Preoperative Comorbidity | 817 (28.7) | 109 (28.1) | 1.4 | 0.795 | 113 (29.7) | 108 (28.4) | 2.9 | 0.690 |
| Chemotherapy and/or Radiation within 6 months | 131 (4.6) | 20 (5.2) | 2.5 | 0.631 | 22 (5.8) | 20 (5.3) | 2.3 | 0.751 |
| Renal Dysfunction | 100 (3.5) | 13 (3.4) | 0.9 | 0.868 | 7 (1.8) | 13 (3.4) | 9.9 | 0.174 |
| FEV1 (% Predicted) | 77.0(31.7) | 73.7(33.0) | 10.6 | 0.048 | 74.5(32.8) | 74.6(32.1) | 0.1 | 0.986 |
| Missing FEV1 | 268 (9.4) | 45 (11.6) | 7.1 | 0.206 | 40 (10.5) | 40 (10.5) | 0 | 0.999 |
| Zubrod Scale | 6.5 | 0.257 | 2.8 | 0.699 | ||||
| 0 | 1,270 (44.7) | 174 (44.9) | 182 (47.8) | 174 (45.7) | ||||
| 1 | 1,374 (48.3) | 177 (45.6) | 169 (44.4) | 176 (46.2) | ||||
| 2 | 168 (5.9) | 29 (7.5) | 27 (7.1) | 29 (7.6) | ||||
| 3 | 27 (1.0) | 2 (0.5) | 2 (0.5) | 2 (0.5) | ||||
| 4 | 5 (0.2) | 6 (1.6) | 1 (0.3) | 0 (0.0) | ||||
| Intraoperative Factors | ||||||||
| Blood Product Use (Y/N)* | 55 (1.9) | 4 (1.0) | 7.5 | 0.117 | 7 (1.8) | 4 (1.1) | 6.6 | 0.363 |
| Fluid Balance | 1311(797.5) | 1185.9(816.6) | 15.5 | 0.004 | 1145.1(757.7) | 1197.8(816) | 6.7 | 0.356 |
| Surgical Duration | 162.8(97.5) | 165.3(102.5) | 2.52 | 0.636 | 173.3(106.9) | 165.6(102) | 7.759 | 0.309 |
| Anesthesia Duration | 247.9(106.4) | 252.6(111.1) | 4.3 | 0.420 | 261.4(117.1) | 252.8(110.8) | 7.51 | 0.300 |
| Surgical Type | ||||||||
| Segmentectomy | 135 (4.8) | 21 (5.4) | 3 | 0.566 | 14 (3.7) | 21 (5.5) | 8.8 | 0.226 |
| Lobectomy | 1,405 (49.4) | 167 (43.0) | 12.8 | 0.019 | 188 (49.3) | 167 (43.8) | 11.1 | 0.128 |
| Bilobectomy | 93 (3.3) | 16 (4.1) | 4.5 | 0.423 | 17 (4.5) | 16 (4.2) | 1.3 | 0.859 |
| Pneumonectomy | 84 (3.0) | 7 (1.8) | 7.5 | 0.125 | 10 (2.6) | 6 (1.6) | 7.3 | 0.313 |
| Wedge Resection | 1,127 (39.6) | 177 (45.6) | 12.1 | 0.024 | 152 (39.9) | 171 (44.9) | 10.1 | 0.164 |
| Surgical Approach | 3.4 | 0.537 | 8.1 | 0.243 | ||||
| Thoracotomy | 805 (28.3) | 104 (26.8) | 116 (30.5) | 102 (26.8) | ||||
| Video-assisted thoracoscopic surgery | 2,039 (71.7) | 284 (73.2) | 268 (70.0) | 279 (73.2) | ||||
| Median Physiologic Factors For First 5 to 15 Minutes Following Start of One Lung Ventilation | ||||||||
| Respiratory Rate | 12 (2.7) | 14 (3.1) | 63.2 | <0.001 | 12 (2.6) | 14 (3.3) | 57.6 | <0.001 |
| FIO2 % | 89 (12.5) | 89 (13.5) | 2.1 | 0.704 | 89 (12.5) | 88 (13.6) | 4 | 0.588 |
| Mean Inspiratory Pressure | 11 (2.4) | 11 (2.2) | 9.2 | 0.103 | 10 (2.3) | 10 (2.2) | 0.9 | 0.914 |
| Peak Inspiratory Pressure | 24 (5.3) | 23 (5.7) | 31.9 | <0.001 | 24 (5.1) | 23 (5.5) | 30.4 | <0.001 |
| Plateau Pressure | 21 (5) | 21 (5.7) | 18.6 | 0.025 | 21 (5) | 21 (5.4) | 22.4 | 0.049 |
| ETCO2 | 35 (5.3) | 39 (5.8) | 61.9 | <0.001 | 37 (5.1) | 39 (5.7) | 46.3 | <0.001 |
| Tidal Volume/Predicted Body Weight (ml/kg) | 6.7 (1.4) | 4.4 (0.5) | 217.4 | <0.001 | 6.4(1.2) | 4.4(0.5) | 208.4 | <0.001 |
| PEEP (cm H2O) | 5 (1.7) | 6 (1.1) | 67.7 | <0.001 | 5 (1.8) | 6 (1.1) | 65.4 | <0.001 |
| Modified Driving Pressure | 17 (12.5) | 15 (5.1) | 42.6 | <0.001 | 17 (12.5) | 15 (5.4) | 47 | <0.001 |
Data are presented as frequency (percentage) or mean and standard deviation, as appropriate. Full study cohort comparisons were calculated using t-tests or Mann-Whitney U tests for continuous variables and Chi-Square or Fisher’s Exact tests for categorical variables, as appropriate. Matched population comparisons were calculated using paired t-tests or Wilcoxon signed-rank tests for continuous variables and McNemar tests for categorical variables, as appropriate. There were no standardized differences > 10% for matched factors.
*
Data are presented as percentage of non-missing data
Abbreviations: ASA = American Society of Anesthesiologists, COPD = chronic obstructive pulmonary disease, FEV1 = forced expiratory volume in 1 s, FIO2 = inspired oxygen fraction, PEEP = positive end-expiratory pressure, ETCO2 = end-tidal carbon dioxide.