Table 2.
Multivariate models for 30-day mortality and O-E LOS >2 days. *The P-values for the overall test for TV (ml) per kg IBW for 30-day mortality and LOS O-E >2 days are P<0.015 and P<0.010. NS, not significant
| Variable | 30-day mortality |
O-E LOS >2 days |
||||
|---|---|---|---|---|---|---|
| HR | 95% Confidence limits | P-value | OR | 95% Confidence limits | P-value | |
| TV IBW group (ml kg−1)* | ||||||
| 3–6 | 1.372 | 0.816, 2.307 | 0.2335 | 1.365 | 1.065, 1.748 | 0.0139 |
| 6–8 | 1.611 | 1.249, 2.077 | 0.0002 | 1.108 | 1.024, 1.199 | 0.0109 |
| 8–10 (ref.) | – | – | – | – | – | – |
| 10–12 | 1.056 | 0.694, 1.608 | 0.799 | 0.914 | 0.827, 1.009 | 0.0735 |
| 12–20 | 2.081 | 0.941, 4.602 | 0.0704 | 0.714 | 0.57, 0.893 | 0.0032 |
| Dynamic compliance (ml cm−1 H2O) | ||||||
| 0–25 | 1.403 | 1.041, 1.89 | 0.0263 | 0.716 | 0.648, 0.791 | <0.0001 |
| 25–30 | 0.967 | 0.695, 1.346 | 0.8427 | 0.906 | 0.826, 0.994 | 0.0369 |
| 30–37 (ref.) | – | – | – | – | – | – |
| 37–150 | 0.994 | 0.712, 1.387 | 0.9704 | 1.029 | 0.941, 1.125 | 0.5351 |
| Obstructive disease | ||||||
| with steroid use | 0.527 | 0.194, 1.429 | 0.2078 | NS | NS | NS |
| without steroid use | 1.273 | 0.981, 1.651 | 0.0693 | NS | NS | NS |
| Length of intubation (h) | ||||||
| 0–2 | 1.219 | 0.932, 1.595 | 0.1477 | 0.618 | 0.558, 0.686 | <0.0001 |
| 2–4 (ref.) | – | – | – | – | – | – |
| 4–6 | 0.94 | 0.684, 1.293 | 0.7047 | 1.614 | 1.487, 1.752 | <0.0001 |
| >6 | 1.065 | 0.752, 1.507 | 0.7223 | 3.002 | 2.724 | <0.0001 |
| TT before operating theatre | 2.218 | 1.64, 3 | <0.0001 | NS | NS | NS |
| Age (yr) | ||||||
| <45 (ref.) | – | – | – | – | – | – |
| 45–55 | 1.442 | 0.885, 2.349 | 0.1418 | 1.138 | 1.032, 1.254 | 0.0096 |
| 56–65 | 1.502 | 0.957, 2.36 | 0.0771 | 1.21 | 1.099, 1.332 | 0.0001 |
| >65 | 1.917 | 1.275, 2.882 | 0.0018 | 1.197 | 1.086, 1.319 | 0.0003 |
| Female gender | 1.024 | 0.8, 1.311 | 0.8524 | 1.213 | 1.127, 1.307 | <0.0001 |
| Race | ||||||
| White (ref.) | – | – | – | – | – | – |
| Asian | 0.553 | 0.29, 1.057 | 0.0731 | NS | NS | NS |
| Black | 0.911 | 0.671, 1.236 | 0.5492 | NS | NS | NS |
| Hispanic | 1.064 | 0.771, 1.468 | 0.7075 | NS | NS | NS |
| Other | 0.908 | 0.653, 1.262 | 0.564 | NS | NS | NS |
| BMI group (kg m−2) | ||||||
| 10–18.5 | 1.273 | 0.822, 1.972 | 0.2797 | 0.885 | 0.728, 1.075 | 0.2192 |
| 18.6–25 (ref.) | – | – | – | – | – | – |
| 25–30 | 0.869 | 0.672, 1.123 | 0.2832 | 1.001 | 0.923, 1.087 | 0.9733 |
| 30–35 | 0.757 | 0.535, 1.069 | 0.1141 | 1.186 | 1.071, 1.315 | 0.0011 |
| >35 | 0.573 | 0.35, 0.937 | 0.0266 | 1.202 | 1.061, 1.361 | 0.0037 |
| ASA physical status | ||||||
| I or II | 0.332 | 0.165, 0.669 | 0.002 | 0.889 | 0.821, 0.962 | 0.0035 |
| III (ref.) | – | – | – | – | – | – |
| IV or V | 1.967 | 1.511, 2.562 | <0.0001 | 1.066 | 0.945, 1.202 | 0.3004 |
| APR-DRG SOI | ||||||
| Minor | – | – | – | – | – | – |
| Moderate | 1.282 | 0.551, 2.982 | 0.5643 | 1.237 | 1.142, 1.341 | <0.0001 |
| Severe | 1.665 | 0.652, 4.252 | 0.2862 | 1.125 | 0.99, 1.278 | 0.0711 |
| Extreme | 3.615 | 1.368, 9.554 | 0.0096 | 1.616 | 1.298, 2.011 | <0.0001 |
| APR-DRG ROM | ||||||
| Minor | – | – | – | – | – | – |
| Moderate | 1.793 | 0.832, 3.865 | 0.136 | 1.092 | 0.992, 1.202 | 0.0722 |
| Severe | 8.142 | 3.626, 18.284 | <0.0001 | 1.361 | 1.166, 1.589 | <0.0001 |
| Extreme | 30.193 | 12.908, 70.624 | <0.0001 | 1.653 | 1.289, 2.121 | <0.0001 |
| Laparoscopic surgery | 0.933 | 0.701, 1.241 | 0.6336 | 0.633 | 0.579, 0.692 | <0.0001 |
| General surgery | 1.173 | 0.898, 1.532 | 0.242 | 1.526 | 1.416, 1.644 | <0.0001 |
| Emergency | 1.154 | 0.896, 1.486 | 0.2663 | 1.193 | 1.058, 1.346 | 0.0039 |
| Year of service | ||||||
| 2008 | 1.064 | 0.782, 1.447 | 0.6932 | 0.837 | 0.764, 0.918 | 0.0002 |
| 2009 | 1.001 | 0.736, 1.362 | 0.9958 | 0.642 | 0.585, 0.704 | <0.0001 |
| 2010 | 0.833 | 0.609, 1.139 | 0.2517 | 0.654 | 0.597, 0.716 | <0.0001 |
| 2011 (ref.) | – | – | – | – | – | – |