[Four years of raw mortality in an intensive care unit]

To characterize magnitude and variability of raw mortality in a Mexican Intensive Care Unit (ICU).

Demographic and clinical data were analyzed in 1,746 patients discharged from the ICU of the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran. The data was obtained from an administrative database and covered four years (2003-2006).

Overall ICU-mortality was 23% (410/1746) and was associated with two binary variables (higher mortality in weekend admissions and non-surgical cases) and three multicategorical variables (gradient of increasing mortality with increasing age, increasing diagnostic risk and increasing number of high-rish diagnoses). First biennium mortality was significantly higher than in the second biennium (29% us 19%). This higher mortality was not associated with the high risk categories of the five variables described above nor with other ICU-variables such as number of nurses and admission and discharge criteria. The only biennium difference was a higher number of physicians (specialists + residents) in the second biennium (16-20 versus 14-15 in the first).

The four-year long-term ICU-mortality showed a significant decrease in the second biennium. Number of physicians was the only variable associated with the decreased mortality.