Sepsis and Septic Shock

Sepsis was defined by an international consensus panel in 1992 as a systemic inflammatory response to infection, which was caused by multiple infectious agents. The term severe sepsis was applied to describe cases of sepsis which were complicated by acute organ dysfunction (Angus & van der Poll, 2013).

The third international consensus definitions for sepsis and septic shock (Sepsis-3) were recently published. Septic shock was defined as a subset of sepsis in which underlying circulatory, cellular and metabolic abnormalities are associated with a greater risk of mortality than sepsis alone (Shankar-Hari et al., 2016).

A recent analysis of a national inpatient database in the United States identified older age (aged 60–69 years) and comorbidities including diabetes, liver disease, renal failure and solid tumours as risk factors for septic shock. A significant downward trend in mortality for inpatients with septic shock from 2005 to 2011 was reported: from 46% in 2005 to 42% in 2011 (Ptrend =0.003). Multivariate adjusted mortality was also significantly reduced with an odds ratio (OR) of 0.98 (95% CI, 0.96–1.00; p<0.001) for adjusted mortality in 2005 compared with 2011 (Goto et al., 2016).

Treatment of sepsis with fluid bolus therapy has been recommended for both adult and paediatric patients with sepsis when circulatory failure occurs. However, there are concerns with large-volume fluid bolus therapy, as this method has been associated with worsening renal function, acute respiratory distress syndrome, prolonged Intensive Care Unit (ICU) stay and hospital length of stay. A recent prospective observational cohort study investigated the effect fluid bolus therapy has on cardiac index in children with sepsis. Cardiac index is an assessment of the cardiac output value based on the patient’s size. The study enrolled 41 children that received a total of 49 fluid boluses. Transthoracic echocardiography was recorded prior to, 5 minutes after, and 60 minutes after fluid bolus therapy, and cardiac index was then calculated from this.

The study revealed a median change in cardiac index 5 minutes after fluid bolus therapy of +18% (IQR 8.6–28.1%). Furthermore, 31 of the fluid boluses (63%) achieved an increase of more than 10% at 5 minutes, these patients were considered fluid responsive. However, after 60 minutes the median change in cardiac index fell to -6% (IQR -15.2%–3.0%). For the majority of patients, increased cardiac index wasn’t sustained over time, with only 4 of the fluid responsive patients (14%) sustaining an increased cardiac index at 60 minutes. Further research is required to assess alternative acute circulatory support (Long et al., 2018).