Impact of empirical antibiotic therapy and mortality in the elderly with septic shock

Background

There are still questions on early implementation of correct empirical antibiotic therapy and its association with mortality reduction in septic shock (SS).

Objective

To evaluate the impact of the use of empirical antibiotics on elderly mortality with SS in the ICU.

Methods

A prospective cohort of 67 patients over 65 years old followed-up during 32 months and with pulmonary artery monitoring due to SS. Cultures were achieved in the first 24 hours. Ventilator and hemodynamic support, volume resuscitation and empirical antibiotic support with large spectrum were also employed. The choice of the antibiotics was based upon a probable community-acquired or hospital infection, and it was considered adequate when at least one effective drug had been included. Previous diseases, organic failures, and APACHE II scores were also evaluated. As for the statistical analysis, the t test, the chi-square test and Kaplan–Meier survival curve analyses were applied, considering 5% as the significance level.

Results

The average ranges were: for age (80 ± 7), for APACHE (19 ± 5), for ICU stay (18 ± 9 days), where 51% were women. Among the previous diseases one can point out systemic arterial hypertension in 40%, ischemic heart disease in 31%, stroke in 21% and the COPD in 30% of the cases. Pulmonary SS alone occurred in 70% of the cases, and in association with urinary SS in 27%. The blood cultures were positive in 10% of the samples. The Gram-negative pathogens were responsible for 79% of the infections, where 36% were due to Pseudomonas. The multidrug-resistant microorganisms represented 8% of the cultures. Thirty-nine deaths occurred during the stay in the ICU. The antibiotics used in the empirical form were correct in 87% of the patients and they were modified in around 72 hours when clinical worsening or inadequate antimicrobial susceptibility patterns result took place. There was no association between age (P = 0.22) or adequate empirical antibiotic therapy and mortality, but mortality was associated with APACHE score (P < 0.001) and organic failures (P = 0.006). The ICU length of stay was not correlated with the use of adequate empirical antibiotics (P = 0.66).

Conclusion

The adequate and early empirical antibiotic therapy was not associated with mortality or with the ICU stay of the elderly with SS. Possibly, the high level of correct choices of the antibiotic scheme and its modification due to clinical failure and inadequate antimicrobial susceptibility patterns have contributed to the results.