Severe Sepsis and Septic Shock: Timing of Septic Shock Onset Matters

Introduction: Timing of septic shock onset may play a prognostic role in severe sepsis; however, clinical evidence provides contradictory results. This study aimed to investigate possible associations between timing of onset of septic shock and patient outcome. Methods: In a university-affiliated hospital, all patients admitted to the intensive care unit (ICU) for severe sepsis or septic shock from November 2007 to March 2011 were included. The primary outcome of interest was the impact of timing of septic shock onset on in-hospital mortality. We also sought to identify potential factors predicting development of septic shock after ICU admission. Results: In total, 772 patients were identified to have severe sepsis; approximately two-thirds (487/772) of them experienced septic shock and overall in-hospital mortality was 57%. Timing of onset of septic shock was an independent predictor of in-hospital outcome, and there was an increasing trend of in-hospital mortality with later onset of septic shock. In addition, timing of septic shock onset provided further mortality risk stratification in patients with APACHE II scores of less than 20 and 20 to 25. We also found that patients who underwent cardiovascular surgery were more likely to experience septic shock after admission and those receiving neurosurgery were at lower risk of developing septic shock. Conclusions: This study showed the significance of timing of septic shock onset in prognosis among ICU patients with severe sepsis. Timing of shock onset further stratified patients with similar disease severity into different mortality risk groups. These findings deliver useful information regarding risk stratification of septic patients.