Table 1 Comparisons of demographic, preoperative, and intraoperative data between the low and high PIP groups before and after propensity score matching
Before propensity score matching | After propensity score matching | |||||
|---|---|---|---|---|---|---|
Low PIP group* (n = 1338) | High PIP group† (n = 318) | P value | Low PIP group* (n = 206) | High PIP group† (n = 206) | P value | |
Demographics | ||||||
Male sex | 604 (45.1%) | 150 (47.2%) | 0.555 | 95 (46.1%) | 93 (45.1%) | 0.486 |
Age (year) | 58.6 (46.8–67.2) | 59.1 (47.4–67.8) | 0.599 | 59.5 (48.6–68.0) | 59.0 (46.5–68.9) | 0.515 |
BMI (kg/m2) | 24.0 (21.8–26.2) | 26.3 (24.0-28.7) | < 0.001 | 25.1 (23.0-27.8) | 25.5 (23.5–28.2) | 0.390 |
ASA physical status | 0.004 | 0.382 | ||||
1 | 297 (22.2%) | 42 (13.2%) | < 0.001 | 36 (17.5%) | 32 (15.5%) | 0.691 |
2 | 936 (70.0%) | 246 (77.4%) | 0.011 | 159 (77.2%) | 157 (76.2%) | 0.907 |
3 | 92 (6.9%) | 29 (9.1%) | 0.207 | 10 (4.9%) | 17 (8.3%) | 0.232 |
4 | 12 (0.9%) | 1 (0.3%) | 0.483 | 1 (0.5%) | 0 (0.0%) | 1.000 |
5 | 1 (0.1%) | 0 (0.1%) | 1.000 | 0 (0.0%) | 0 (0.0%) | NA |
Comorbidity | ||||||
Hypertension | 420 (31.4%) | 118 (37.1%) | 0.059 | 68 (33.0%) | 73 (35.4%) | 0.678 |
Diabetes mellitus | 177 (13.2%) | 57 (17.9%) | 0.038 | 34 (16.5%) | 31 (15.0%) | 0.787 |
Asthma | 17 (1.3%) | 6 (1.9%) | 0.422 | 5 (2.4%) | 4 (1.9%) | 1.000 |
COPD | 15 (1.1%) | 5 (1.6%) | 0.565 | 2 (1.0%) | 3 (1.5%) | 1.000 |
Smoking | 213 (15.9%) | 78 (24.5%) | < 0.001 | 37 (18.0%) | 40 (19.4%) | 0.800 |
Obesity | 60 (4.5%) | 54 (17.0%) | < 0.001 | 28 (13.6%) | 18 (8.7%) | 0.159 |
Cardiac disease | 90 (6.7%) | 33 (10.4%) | 0.035 | 18 (8.7%) | 21 (10.2%) | 0.736 |
Pulmonary disease | 69 (5.2%) | 19 (6.0%) | 0.656 | 11 (5.3%) | 12 (5.8%) | 1.000 |
Hepatic disease | 73 (5.5%) | 27 (8.8%) | 0.035 | 19 (9.2%) | 16 (7.8%) | 0.724 |
Renal disease | 64 (4.8%) | 18 (5.7%) | 0.614 | 8 (3.9%) | 11 (5.3%) | 0.639 |
Surgery | ||||||
Type | 0.002 | 0.420 | ||||
Cranial | 950 (71.0%) | 197 (61.9%) | 120 (58.3%) | 129 (62.6%) | ||
Spinal | 388 (29.0%) | 121 (38.1%) | 86 (41.7%) | 77 (37.4%) | ||
Position | 0.117 | 0.109 | ||||
Supine | 906 (67.7%) | 196 (61.6%) | 0.046 | 123 (50.0%) | 123 (50.0%) | 1.000 |
Prone | 398 (29.7%) | 113 (35.5%) | 0.052 | 79 (38.3%) | 71 (34.5%) | 0.474 |
Lateral | 34 (2.5%) | 9 (2.8%) | 0.924 | 4 (1.9%) | 12 (5.8%) | 0.074 |
Duration (min) | 165.0 (105.0-250.0) | 185.5 (115.0-250.0) | 0.015 | 170.0 (105.0-251.3) | 183.0 (105.0-260.0) | 0.622 |
Duration > 200.5 min | 495 (37.0%) | 143 (45.0%) | 0.009 | 78 (37.9%) | 88 (42.7%) | 0.315 |
Anesthesia | ||||||
BIS monitoring | 545 (40.7%) | 117 (36.8%) | 0.220 | 83 (40.3%) | 80 (38.8%) | 0.840 |
BIS value | 38.4 (29.9–45.3) | 38.7 (28.4–45.9) | 0.800 | 38.9 (31.0-43.4) | 38.4 (28.8–45.5) | 0.963 |
fEMG (dB) | 27.9 (26.5–30.9) | 28.7 (26.6–32.7) | 0.083 | 27.1 (26.2–30.6) | 29.1 (26.8–33.0) | 0.007 |
Ce | ||||||
Propofol (µg/kg) | 3.5 (3.0–4.0) | 3.5 (2.8-4.0) | 0.363 | 3.5 (2.5-4.0) | 3.5 (2.7–4.3) | 0.173 |
Remifentanil (ng/kg) | 3.5 (2.8-4.0) | 3.5 (2.8–4.1) | 0.623 | 3.5 (2.6-4.0) | 3.5 (3.0-4.2) | 0.367 |
Ventilation | ||||||
PIP (cmH2O) | 18.0 (16.0-19.4) | 23.1 (22.1–24.9) | < 0.001 | 19.0 (17.2–20.1) | 23.0 (22.0-24.1) | < 0.001 |
PEEP (cmH2O) | 5.0 (5.0–5.0) | 7.1 (5.0-8.1) | < 0.001 | 5.1 (5.0-7.9) | 5.1 (5.0-7.9) | 0.660 |
TV/PBW (mL/kg) | 7.5 (7.0-7.8) | 7.7 (7.2–8.1) | < 0.001 | 7.6 (7.2-8.0) | 7.6 (7.2-8.0) | 0.889 |
TV/PBW > 7.9 mL/kg | 276 (20.6%) | 108 (34.0%) | < 0.001 | 55 (26.7%) | 64 (31.1%) | 0.328 |
Intraoperative coughing | 16 (1.2%) | 14 (4.4%) | < 0.001 | 1 (0.5%) | 13 (6.3%) | 0.003 |