SIRS - Out, SOFA - In: The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3)

For some time there has been growing evidence that the current definition of sepsis and septic shock is inaccurate. In fact, 1 in 8 patients admitted to critical care units in Australia and New Zealand with infection and new organ failure did not have the requisite minimum of 2 SIRS criteria to fulfil the definition of sepsis and had protracted courses with significant morbidity and mortality (Kaukonen et al. Systemic inflammatory response syndrome criteria in defining severe sepsis. N Engl J Med. 2015;372(17):1629-1638). 

The new definitions of Sepsis and Septic Shock were published in this week’s JAMA. These were written by a taskforce with expertise in sepsis pathobiology, clinical trials, and epidemiology which was was convened by the Society of Critical Care Medicine and the European Society of Intensive Care Medicine. They are titled: The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3).

The article is attached and can be downloaded here (open access). 

Key points:

Concepts of Sepsis:

  • Sepsis is the primary cause of death from infection, especially if not recognised and treated promptly. Its recognition mandates urgent attention. 
  • Sepsis is a syndrome shaped by pathogen factors and host factors (eg, sex, race and other genetic determinants, age, comorbidities, environment) with characteristics that evolve over time. What differentiates sepsis from infection is an aberrant or dysregulated host response and the presence of organ dysfunction. 
  • Sepsis-induced organ dysfunction may be occult; therefore, its presence should be considered in any patient presenting with infection. Conversely, unrecognized infection may be the cause of new-onset organ dysfunction. Any unexplained organ dysfunction should thus raise the possibility of underlying infection. 
  • The clinical and biological phenotype of sepsis can be modified by preexisting acute illness, long-standing comorbidities, medication, and interventions. 
  • Specific infections may result in local organ dysfunction without generating a dysregulated systemic host response. 

New Terms and Definitions:

  • Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection. 
  • Organ dysfunction can be identified as an acute change in total SOFA score 2 points consequent to the infection. 
  • The baseline SOFA score can be assumed to be zero in patients not known to have preexisting organ dysfunction. 
  • A SOFA score 2 reflects an overall mortality risk of approximately 10% in a general hospital population with suspected infection. Even patients presenting with modest dysfunction can deteriorate further, emphasising the seriousness of this condition and the need for prompt and appropriate intervention, if not already being instituted.
  • In lay terms, sepsis is a life-threatening condition that arises when the body’s response to an infection injures its own tissues and organs. 
  • Patients with suspected infection who are likely to have a prolonged ICU stay or to die in the hospital can be promptly identified at the bedside with qSOFA, ie, alteration in mental status, systolic blood pressure 100 mm Hg, or respiratory rate 22/min. 
  • Septic shock is a subset of sepsis in which underlying circulatory and cellular/metabolic abnormalities are profound enough to substantially increase mortality. 
  • Patients with septic shock can be identified with a clinical construct of sepsis with persisting hypotension requiring vasopressors to maintain MAP 65 mm Hg and having a serum lactate level
  • >2 mmol/L (18 mg/dL) despite adequate volume resuscitation. With these criteria, hospital mortality is in excess of 40%. 

qSOFA (Quick SOFA) Criteria: 

  • Respiratory rate 22/min
  • Altered mentation
  • Systolic blood pressure 100 mm Hg