The changing face of organ failure in ARDS.

OBJECTIVE

To study morbidity and mortality in ARDS patients from 1987 to 1999.

DESIGN

Review of a prospectively collected database of ARDS patients.

SETTING

Large, community hospital located in Salt Lake City, UT.

PATIENTS

ARDS patients identified for the years 1987 to 1999. We prospectively identified ARDS patients at LDS Hospital in Salt Lake City, UT, using PaO(2)/fraction of inspired oxygen ratio (P/F) criteria, the presence of bilateral chest radiograph infiltrates, and the absence of left atrial hypertension.

MEASUREMENTS

We assigned a primary risk factor for ARDS and identified the presence of organ failure before and after ARDS. We compared two temporal groups (ie, 1987 to 1990 vs 1994 to 1999) and used two criteria of arterial hypoxemia (P/F: patients from 1994 to 1999, < or = 105 and < or = 173; patients from 1987 to 1990, < or = 0.2) At 1,500 m (the altitude of Salt Lake City), a PaO(2) of < or = 173 corresponds to an alveolar-arterial oxygen pressure difference of < or = 200 at sea level. We used death at hospital discharge as an end point.

MAIN RESULTS

We identified 516 ARDS patients with a P/F of < or = 105 (1987 to 1990, 256 patients; 1994 to 1999, 260 patients). Patients who had ARDS between 1994 and 1999 with a P/F of < or = 105 had a lower mortality rate than patients between 1987 and 1990 with a P/F of < or = 105 (44% vs 54%, respectively; p <.05). There were 288 patients with a P/F range of 106 to 173 during 1994 to 1999. Patients from 1994 to 1999 with a P/F of < or = 173 had a lower mortality rate compared to patients from 1987 to 1990 (35% vs 54%, respectively; p <.01). Patients from 1994 to 1999 (for both P/F groups) had statistically fewer total nonpulmonary organ failures (ie, more patients had zero organ failures or single organ failures) and fewer specific organ failures (ie, sepsis, cardiovascular failures, and CNS failures). There were statistically fewer cases of cardiovascular failure, sepsis, and in both periods (ie, prior to ARDS and after the onset of ARDS) for 1994-to-1999 patients with a P/F of < or = 105 compared to 1987-to-1990 patients with a P/F of < or = 105.

CONCLUSIONS

Mortality from ARDS has decreased and is associated with decreased organ failure prior to and during the course of ARDS.