Association of second antibiotic dose delays on mortality in patients with septic shock

Determine whether a delay in the administration of the second dose of antibiotics is associated with an increased risk of mortality for patients admitted with septic shock.

Retrospective, observational evaluation.

Regional multicenter evaluation including four institutions in western Pennsylvania.

A total of 905 patients were included in this study who met the criteria for septic shock. Patients that did not receive a second dose of antibiotics, were transferred from an outside facility, or expected death within six hours of hospital admission were excluded.

The frequency of second antibiotic dose administration delay was determined. A delay was defined as a delay greater than or equal to 25% of the antibiotic dosing interval.

A delay in second antibiotic dose administration was found in 181 (20%) of patients. Patients with a delay in the administration of second dose antibiotics had a higher mortality rate (35%) than patients without a delay (26%) (p =0.018). Patients with and without a delay in the administration of second-dose antibiotics had similar median 28-day vasopressor free days (median = 26.0, IQR = 2.0). Differences in the distribution of the 28-day vasopressor free days between groups resulted in the achievement of statistical significance (Mann-Whitney U = 57,294.5, z = -2.690, p = 0.006). There was no difference in 28-day ventilator-free days between groups. A delay in the administration of second dose antibiotics led to a longer in-hospital length of stay (9 days vs. 7 days; p = 0.022) and a longer ICU length of stay than patients without a delay (5 days vs. 3 days; p = 0.007).

Delays in second antibiotic dose administration in septic shock patients were present but lower than previous studies. These delays were associated with increased mortality, increased ICU and hospital length of stay.