Table 1. Characteristics of Patients, Anesthesia, and Surgery before and after Propensity Matching.
| Before matching | After matching | |||||
|---|---|---|---|---|---|---|
| Volatile (n = 1519) | Propofol (n = 415) | P value | Volatile (n = 390) | Propofol (n = 390) | P value | |
| Age (yr) | 62.4 ± 13.3 | 61.5 ± 12.4 | 0.219 | 61.7 ± 13.4 | 61.5 ± 12.4 | 0.808 |
| Gender | 0.778 | 0.430 | ||||
| Male | 895 (58.9%) | 248 (59.8%) | 222 (56.9%) | 234 (60.0%) | ||
| Female | 624 (41.1%) | 167 (40.2%) | 168 (43.1%) | 156 (40.0%) | ||
| Height (cm) | 161.4 ± 11.3 | 162.0 ± 10.4 | 0.326 | 161.2 ± 12.4 | 161.9 ± 10.4 | 0.405 |
| Weight (kg) | 61.6 ± 11.2 | 61.9 ± 10.5 | 0.705 | 61.9 ± 11.8 | 61.6 ± 10.5 | 0.773 |
| BMI (kg/m2) | 24.1 ± 10.7 | 23.8 ± 7.7 | 0.598 | 24.6 ± 12.2 | 23.8 ± 7.9 | 0.306 |
| ASA (1/2/3/4/5) | 0.204 | 0.543 | ||||
| 1 | 486 (32.7%) | 121 (29.6%) | 118 (30.3%) | 112 (28.7%) | ||
| 2 | 865 (58.1%) | 261 (63.8%) | 245 (62.8%) | 254 (65.1%) | ||
| 3 | 125 (8.4%) | 26 (6.4%) | 26 (6.7%) | 23 (5.9%) | ||
| 4 | 10 (0.7%) | 1 (0.2%) | 1 (0.3%) | 1 (0.3%) | ||
| 5 | 2 (0.1%) | 0 (0%) | 0 (0%) | 0 (0%) | ||
| Preoperative smoking | 477 (31.4%) | 147 (35.4%) | 0.124 | 121 (29.8%) | 142 (35.0%) | 0.117 |
| Preoperative glucose (mg/dl) | 0.509 | 0.496 | ||||
| < 70 | 13 (0.9%) | 6 (1.4%) | 8 (2.1%) | 5 (1.3%) | ||
| 70–110 | 760 (50.1%) | 211 (51.0%) | 191 (49.0%) | 201 (51.5%) | ||
| > 110 | 744 (49.0%) | 197 (47.6%) | 191 (49.0%) | 184 (47.2%) | ||
| Operation time (h) | 2.8 (1.5) | 3.0 (1.8) | 0.104 | 2.7 (1.4) | 2.8 (1.8) | 0.387 |
| Anesthesia time (h) | 3.6 (1.6) | 3.8 (1.9) | 0.129 | 3.6 (1.5) | 3.7 (1.9) | 0.415 |
| Discharge | 0.055 | 1.000 | ||||
| PACU | 1353 (89.1%) | 383 (92.3%) | 362 (92.8%) | 361 (92.6%) | ||
| ICU | 166 (10.9%) | 32 (7.7%) | 28 (7.2%) | 29 (7.4%) | ||
| Postoperative body temperature (℃) | 35.4 ± 7.6 | 35.4 ± 11.3 | 1.000 | 35.3 ± 8.9 | 35.4 ± 9.5 | 0.879 |
| Postoperative hypothermia (< 35℃) | 301 (19.8%) | 88 (21.2%) | 0.578 | 80 (20.5%) | 85 (21.8%) | 0.726 |
| Postoperative PCA | 0.203 | 0.210 | ||||
| Yes | 1480 (97.4%) | 409 (98.6%) | 379 (97.2%) | 385 (98.7%) | ||
| No | 39 (2.6%) | 6 (1.4%) | 11 (2.8%) | 5 (1.3%) | ||
| Operator | 0.139 | 0.107 | ||||
| A | 715 (47.1%) | 189 (45.5%) | 218 (55.9%) | 180 (46.2%) | ||
| B | 638 (42.0%) | 166 (40.0%) | 124 (31.8%) | 156 (40.0%) | ||
| C | 166 (10.9%) | 60 (14.5%) | 48 (12.3%) | 54 (13.8%) | ||
| Operation name | < 0.001 | 0.056 | ||||
| Colorectal surgery, open | 529 (34.8%) | 99 (23.9%) | 110 (28.2%) | 92 (23.6%) | ||
| Colorectal surgery, laparoscopic | 771 (50.8%) | 215 (51.8%) | 179 (45.9%) | 203 (52.1%) | ||
| APR, open | 32 (2.1%) | 5 (1.2%) | 10 (2.6%) | 5 (1.3%) | ||
| APR, laparoscopic | 28 (1.8%) | 6 (1.4%) | 8 (2.1%) | 6 (1.5%) | ||
| Stoma operation | 159 (10.5%) | 90 (21.7%) | 83 (21.3%) | 84 (21.5%) | ||
| Operation type | 0.912 | 0.126 | ||||
| Open | 716 (47.1%) | 194 (46.7%) | 203 (52.1%) | 181 (46.4%) | ||
| Laparoscopic | 803 (52.9%) | 221 (53.3%) | 187 (47.9%) | 209 (53.6%) | ||
Data are Presented as Mean ± SD or Number (%). BMI: body mass index, ASA: American Society of Anesthesiologist physical status, PACU: post-anesthetic care unit, ICU: intensive care unit, PCA: patient-controlled analgesia, APR: abdominoperineal resection. Data before matching were missing for the following variables: height (missing in 13 cases), weight (missing in 8 cases), BMI (missing in 14 cases), ASA (missing in 37 cases), glucose (missing in 3 cases).