Clinical risk factors for acute respiratory distress syndrome(ARDS) between cases and controls and survivors and nonsurvivors in ARDS
| Risk for ARDS# | Development of ARDS | Mortality in ARDS | ||||
| Controls¶ | Cases+ | p-value | Survivors§ | Nonsurvivorsƒ | p-value | |
| Sepsis syndrome | 163 (38) | 67 (32) | 0.1 | 44 (39) | 23 (23) | 0.02 |
| Pneumonia source | 85 (20) | 52 (25) | <0.001 | 33 (29) | 19 (19) | 0.6 |
| Extrapulmonary source | 78 (18) | 15 (7) | <0.001 | 11 (10) | 4 (4) | |
| Septic shock | 191 (45) | 114 (54) | 0.03 | 51 (45) | 63 (64) | 0.006 |
| Pneumonia source | 85 (20) | 78 (37) | <0.001 | 35 (31) | 43 (44) | >0.9 |
| Extrapulmonary source | 106 (25) | 36 (17) | <0.001 | 16 (14) | 20 (20) | |
| Trauma | 38 (9.0) | 9 (4) | 0.04 | 8 (7) | 1 (1) | 0.04 |
| Multiple transfusions | 50 (12) | 26 (12) | 0.8 | 13 (12) | 13 (13) | 0.8 |
| Aspiration | 32 (7) | 24 (11) | 0.1 | 13 (12) | 11 (11) | >0.9 |
| One or more risk for ARDS | 48 (11) | 29 (14) | 0.3 | 16 (14) | 13 (13) | >0.9 |
| Direct pulmonary injury## | 204 (48) | 143 (68) | <0.001 | 78 (69) | 65 (66) | 0.8 |
| Indirect pulmonary injury¶¶ | 225 (52) | 68 (32) | <0.001 | 35 (31) | 33 (34) | |
Data are presented as n (%), unless otherwise stated. #: numbers of controls and cases with each risk add up to >640 patients because of multiple risks in 75 patients; ¶: n = 429; +: n = 211; §: n = 113; ƒ: n = 98; ##: pneumonia, aspiration or pulmonary contusions were categorised as direct pulmonary injury; ¶¶: sepsis from an extrapulmonary source, trauma without pulmonary contusions and multiple transfusions were categorised as indirect pulmonary injury; patients (n = 69) with both direct and indirect pulmonary injuries were considered to have direct pulmonary injury.