Baseline characteristics of the development and validation cohorts
| Variables | Development cohort | Validation cohort | ||||||
| Weaning failure (n=995) | Weaning success (n=1591) | Total (n=2586) | P value | Total (n=1109) | Weaning success (n=683) | Weaning failure (n=426) | P value | |
| Age (years) | 0.474 | 0.417 | ||||||
| ≤65 | 1170 (45.2) | 711 (44.7) | 459 (46.1) | 514 (46.3) | 310 (45.4) | 204 (47.9) | ||
| >65 | 1416 (54.8) | 880 (55.3) | 536 (53.9) | 595 (53.7) | 373 (54.6) | 222 (52.1) | ||
| Gender | 0.664 | 0.097 | ||||||
| Female | 1121 (43.3) | 695 (43.7) | 426 (42.8) | 472 (42.6) | 304 (44.5) | 168 (39.4) | ||
| Male | 1465 (56.7) | 896 (56.3) | 569 (57.2) | 637 (57.4) | 379 (55.5) | 258 (60.6) | ||
| BMI (kg/m2) | 27.9 (24.5–32.4) | 27.6 (24.4–31.6) | 28.4 (24.7–34.0) | 0.001 | 27.9 (24.3–32.7) | 27.8 (24.2–32.3) | 28.4 (24.6–33.2) | 0.194 |
| Smoking history | 0.740 | 0.288 | ||||||
| No | 2353 (91.0) | 1450 (91.1) | 903 (90.8) | 1027 (92.6) | 637 (93.3) | 390 (91.5) | ||
| Yes | 233 (9.0) | 141 (8.9) | 92 (9.2) | 82 (7.4) | 46 (6.7) | 36 (8.5) | ||
| SOFA | 7 (4–10) | 6 (4–9) | 8 (5–11) | <0.001 | 7 (5–10) | 7 (4–9) | 8 (5–11) | <0.001 |
| Hypertension | 0.543 | 0.917 | ||||||
| No | 1537 (59.4) | 953 (59.9) | 584 (58.7) | 679 (61.2) | 419 (61.3) | 260 (61.0) | ||
| Yes | 1049 (40.6) | 638 (40.1) | 411 (41.3) | 430 (38.8) | 264 (38.7) | 166 (39.0) | ||
| Diabetes mellitus | 0.108 | 0.702 | ||||||
| No | 1807 (69.9) | 1130 (71.0) | 677 (68.0) | 750 (67.6) | 459 (67.2) | 291 (68.3) | ||
| Yes | 779 (30.1) | 461 (29.0) | 318 (32.0) | 359 (32.4) | 224 (32.8) | 135 (31.7) | ||
| COPD | 0.839 | 0.888 | ||||||
| No | 2428 (93.9) | 1495 (94.0) | 933 (93.8) | 1011 (91.2) | 622 (91.1) | 389 (91.3) | ||
| Yes | 158 (6.1) | 96 (6.0) | 62 (6.2) | 98 (8.8) | 61 (8.9) | 37 (8.7) | ||
| Congestive heart failure | 0.286 | 0.455 | ||||||
| No | 1840 (71.2) | 1144 (71.9) | 696 (69.9) | 748 (67.4) | 455 (66.6) | 293 (68.8) | ||
| Yes | 746 (28.8) | 447 (28.1) | 299 (30.1) | 361 (32.6) | 228 (33.4) | 133 (31.2) | ||
| Chronic kidney disease | 0.336 | 0.308 | ||||||
| No | 2019 (78.1) | 1252 (78.7) | 767 (77.1) | 838 (75.6) | 509 (74.5) | 329 (77.2) | ||
| Yes | 567 (21.9) | 339 (21.3) | 228 (22.9) | 271 (24.4) | 174 (25.5) | 97 (22.8) | ||
| Stroke | 0.766 | 0.159 | ||||||
| No | 2079 (80.4) | 1282 (80.6) | 797 (80.1) | 883 (79.6) | 553 (81.0) | 330 (77.5) | ||
| Yes | 507 (19.6) | 309 (19.4) | 198 (19.9) | 226 (20.4) | 130 (19.0) | 96 (22.5) | ||
| VT (mL) | 451 (394–510) | 452 (392–519) | 449 (397–505) | 0.272 | 452 (396–515) | 451 (391–520) | 454 (401–512) | 0.681 |
| RR (bpm) | <0.001 | <0.001 | ||||||
| ≤20 | 1621 (62.7) | 1091 (68.6) | 530 (53.3) | 689 (62.1) | 454 (66.5) | 235 (55.2) | ||
| >20 | 965 (37.3) | 500 (31.4) | 465 (46.7) | 420 (37.9) | 229 (33.5) | 191 (44.8) | ||
| PEEP (cmH2O) | <0.001 | <0.001 | ||||||
| <5 | 312 (12.1) | 268 (16.8) | 44 (4.4) | 146 (13.2) | 122 (17.9) | 24 (5.6) | ||
| 5–8 | 1575 (60.9) | 1071 (67.3) | 504 (50.7) | 674 (60.8) | 460 (67.3) | 214 (50.2) | ||
| ≥8 | 699 (27.0) | 252 (15.8) | 447 (44.9) | 289 (26.1) | 101 (14.8) | 188 (44.1) | ||
| Pplat (cmH2O) | 17.5 (15.0–20.4) | 17.0 (14.0–20.0） | 19.0 (16.0–22.0) | <0.001 | 17.5 (15.0–21.0) | 17.0 (14.0–20.0) | 19.0 (15.5–22.0) | <0.001 |
| Ppeak (cmH2O) | <0.001 | <0.001 | ||||||
| ≤20 | 1325 (51.2) | 1035 (65.1) | 290 (29.1) | 585 (52.8) | 452 (66.2) | 133 (31.2) | ||
| 20–25 | 699 (27.0) | 362 (22.8) | 337 (33.9) | 283 (25.5) | 142 (20.8) | 141 (33.1) | ||
| ≥25 | 562 (21.7) | 194 (12.2) | 368 (37.0) | 241 (21.7) | 89 (13.0) | 152 (35.7) | ||
| MP (J/min) | <0.001 | <0.001 | ||||||
| ≤5 | 303 (11.7) | 285 (17.9) | 18 (1.8) | 144 (13.0) | 136 (19.9) | 8 (1.9) | ||
| 5–10 | 781 (30.2) | 597 (37.5) | 184 (18.5) | 336 (30.3) | 246 (36.0) | 90 (21.1) | ||
| 10–15 | 743 (28.7) | 418 (26.3) | 325 (32.7) | 307 (27.7) | 181 (26.5) | 126 (29.6) | ||
| ≥15 | 759 (29.4) | 291 (18.3) | 468 (47.0) | 322 (29.0) | 120 (17.6) | 202 (47.4) | ||
| Cdyn (mL/cmH2O) | <0.001 | <0.001 | ||||||
| ≥50 | 618 (23.9) | 545 (34.3) | 73 (7.3) | 279 (25.2) | 248 (36.3) | 31 (7.3) | ||
| 40–50 | 321 (12.4) | 214 (13.5) | 107 (10.8) | 141 (12.7) | 89 (13.0) | 52 (12.2) | ||
| 30–40 | 669 (25.9) | 373 (23.4) | 296 (29.7) | 279 (25.2) | 145 (21.2) | 134 (31.5) | ||
| ≤30 | 978 (37.8) | 459 (28.8) | 519 (52.2) | 410 (37.0) | 210 (29.4) | 209 (49.1) | ||
| FiO2 (%) | <0.001 | <0.001 | ||||||
| ≤40 | 1552 (60.0) | 1075 (67.6) | 477 (47.9) | 687 (61.9) | 479 (70.1) | 208 (48.8) | ||
| >40 | 1034 (40.0) | 516 (32.4) | 518 (52.1) | 422 (38.1) | 204 (29.9) | 218 (51.2) | ||
| WBC (×109/L) | 11.8 (8.8–15.8) | 11.4 (8.5–15.3) | 12.6 (9.3–16.8) | <0.001 | 11.8 (9.0–15.2) | 11.5 (8.9–14.7) | 12.4 (9.3–15.8) | 0.014 |
| SCr (mg/dL) | <0.001 | 0.276 | ||||||
| ≤1.1 | 1235 (47.8) | 818 (51.4) | 417 (41.9) | 528 (47.6) | 334 (48.9) | 194 (45.5) | ||
| >1.1 | 1351 (52.2) | 773 (48.6) | 578 (58.1) | 581 (52.4) | 349 (51.1) | 232 (54.5) | ||
| Uorate (mL/kg/h) | 0.001 | 0.037 | ||||||
| ≤0.63 | 1281 (49.5) | 747 (47.0) | 534 (53.7) | 521 (47.0) | 304 (44.5) | 217 (50.9) | ||
| >0.63 | 1305 (50.5) | 844 (53.0) | 461 (46.3) | 588 (53.0) | 379 (55.5) | 209 (49.1) | ||
| HR (bpm) | 0.036 | 0.001 | ||||||
| ≤90 | 1658 (64.1) | 1045 (65.7) | 613 (61.6) | 729 (65.7) | 474 (69.4) | 255 (59.9) | ||
| >90 | 928 (35.9) | 546 (34.3) | 382 (38.4) | 380 (34.3) | 209 (30.6) | 171 (40.1) | ||
| BF (bpm) | 18.5 (16.0–22.0) | 18.0 (15.0–21.0) | 20.0 (16.5–24.0) | <0.001 | 18.5 (15.5–22.0) | 18.0 (15.0–21.5) | 20.0 (16.0–23.8) | <0.001 |
| MBP (mm Hg) | 75 (68–84) | 76 (68–86) | 74 (67–82) | <0.001 | 75 (68–84) | 75 (68–85) | 74 (68–84) | 0.189 |
| SPO2 (%) | 98 (97–100) | 99 (97–100) | 98 (96–100) | <0.001 | 98 (96–100) | 99 (97–100) | 98 (96–100) | 0.001 |
| PH | 7.39 (7.34–7.44) | 7.40 (7.35–7.44) | 7.38 (7.33–7.43) | 0.003 | 7.40 (7.34–7.44) | 7.40 (7.36–7.44) | 7.38 (7.32–7.44) | 0.006 |
| PO2 (mm Hg) | 106 (85–130) | 108 (86–132) | 104 (84–128) | 0.336 | 105 (84–131) | 104 (87–132) | 107 (81–130) | 0.755 |
| PCO2 (mm Hg) | 39 (34–44) | 39 (34–44) | 39 (34–45) | 0.856 | 39 (34–45) | 38 (34–44) | 39 (34–46) | 0.636 |
| PF (mm Hg) | 242 (182–320) | 254 (195–333) | 228 (166–305) | <0.001 | 238 (174–325) | 248 (189–338) | 226 (160–310) | 0.012 |
| ICU days | <0.001 | <0.001 | ||||||
| <7 | 1341 (51.9) | 1047 (65.8) | 294 (29.5) | 564 (50.9) | 447 (65.4) | 117 (27.5) | ||
| ≥7 | 1245 (48.1) | 544 (34.2) | 701 (70.5) | 545 (49.1) | 236 (34.6) | 309 (72.5) | ||
| IMV duration | <0.001 | <0.001 | ||||||
| <3 | 1344 (52.0) | 1057 (66.4) | 287 (28.8) | 570 (51.4) | 453 (66.3) | 117 (27.5) | ||
| ≥3 | 1242 (48.0) | 534 (90.4) | 708 (71.2) | 539 (48.6) | 230 (33.7) | 309 (72.5) | ||
Data are median (IQR) or n/total (%).
BF, breathing frequency; BMI, body mass index; Cdyn, dynamic lung compliance; COPD, chronic obstructive pulmonary disease; FiO2, inspired oxygen concentration; ICU, intensive care unit; IMV, invasive mechanical ventilation; MBP, mean blood pressure; MP, mechanical power; PEEP, positive end-expiratory pressure; PF, arterial partial pressure of oxygen (PaO2) divided by the inspired oxygen concentration (FiO2); Ppeak, peak inspiratory pressure; Pplat, plateau pressure; RR, respiratory rate; SCr, serum creatinine; SOFA, Sequential Organ Failure Assessment; SPO2, pulse oximetry; Uorate, urine output rate; VT, tidal volume; WBC, white blood cell.