Mortality-associated factors in old patients with severe sepsis or septic shock in the medical intensive care unit

Introduction

With the aging of the population, the old-aged will represent a large portion of the patients admitted to the ICU presenting singular characteristics that need to be studied.

Methods

A cohort of 104 old-aged patients with severe sepsis or septic shock, according to the 1992 Consensus, during January 2005–November 2006 was studied. The starting point was systolic arterial pressure under 100 mmHg, and the exclusion criteria were: presence of advanced neoplasia, excuse to sign the free consent term and transfer from the ICU. The variables used were: SOFA score, CRP, lactate and albumin on days 1, 3, 5, 7, 14 and 28, APACHE II score, troponin I, BNP, number of organic failures, cardiovascular diseases before the sepsis, need for mechanical ventilation, length of ICU stay, presence of hypoglycemia and echocardiogram parameters. For the statistical analyses, we used Student's t test and the Fisher Exact test, the chi-square test and Spearman's correlation considering a significant level of 5%.

Results

The average age was 83 ± 8 years (minimum = 60, maximum = 99) and 65% were female. Septic shock represented 71% of cases and the mortality was 44%. The average length of ICU stay was 16 ± 9 days (minimum = 1, maximum = 28). The average APACHE II score was 19 ± 6 (minimum = 6, maximum = 44) and the average SOFA scores on days 1, 3, 5, 7, 14, 28 were 8 ± 3, 8 ± 4, 7 ± 4, 7 ± 3, 8 ± 3, respectively. The variables associated with mortality were: SOFA score on days 1, 3, 5, 7, 14 and 28 (P = 0.00010), CRP on days 5, 14 and 28 (P = 0.03, P = 0.005 and P = 0.02, respectively), lactate on days 14 and 28 (P = 0.023 and P = 0.005), albumin on days 14 and 28 (P = 0.00010), APACHE II score (P = 0.44), presence of two or more organic failures (P = 0.0001), need for mechanical ventilation (P = 0.001) and length of ICU stay (P = 0.002).

Conclusion

The SOFA score, APACHE II score, number of organic failures and the need for mechanical ventilation were associated with mortality from the beginning admission to the ICU, while the metabolic and inflammatory parameters were associated with late mortality. These variables should be studied as potential candidates for the models of prediction of death in the aged.