Table 3.
Baseline respiratory physiology and ventilatory parameters in trauma versus nontrauma lung injury patients
| Parameter | Trauma (n = 141) | Nontrauma (n = 1307) | p Value |
|---|---|---|---|
| Respiratory rate, total | 18 (7) | 21 (7) | <.001 |
| Minute ventilation, L | 11.6 (3.9) | 12.8 (4.1) | <.001 |
| Tidal volume, mL | 663 (184) | 635 (173) | .09 |
| Tidal volume/PBW, mL/kg | 9.8 (2.7) | 10.0 (2.7) | .39 |
| PEEP, median (IQR), cm H2O | 10 (5–12) | 8 (5–10) | .038 |
| Plateau pressure, cm H2Oa | 30.7 (8.0) | 28.7 (7.7) | .018 |
| Peak pressure, cm H2O | 39.8 (11.0) | 35.1 (9.4) | <.001 |
| Pao2/Fio2 ratio, median (IQR) | 164 (108–202) | 114 (82–157) | <.001 |
| Clinical Lung Injury score, median (IQR)b | 2.75 (2.25–3) | 2.75 (2.5–3.25) | .10 |
| Quasistatic compliance, mL/cm H2O | 32.0 (15.7) | 32.7 (26.0) | .70 |
| Mean airway pressure, cm H2O | 16.5 (5.8) | 15.6 (5.2) | .11 |
| Paco2, mm Hg | 40.5 (7.1) | 37 (8.7) | <.001 |
| Arterial pH | 7.41 (0.06) | 7.39 (0.08) | .03 |
PBW, predicted body weight; PEEP, positive end-expiratory pressure; IQR, interquartile range.
a
Trauma patients were more likely to be missing plateau pressure: 41/141 (29%) vs. 273/1310 (21%); odds ratio 1.56 (1.06–2.29)
b
calculated as Murray et al (30). All values represent mean (sd) except where indicated; all values from within 24 hrs before enrollment. Comparisons made with Student's t-test with unequal variance assumption or Mann-Whitney U test where appropriate.