Systemic inflammatory response syndrome

The systemic inflammatory response syndrome (SIRS) refers to a pathophysiological state in patients with a critical non-infectious or infectious illness. It is non-specific and although commonly associated with sepsis can be seen in many life-threatening illnesses.

Clinical presentation


Two or more of the features below are by definition present :

  • fever (>38°C) or hypothermia (<36°C)
  • heart rate of over 90 beats per minute
  • respiratory rate over 20 breaths per minute or an arterial CO2 less than 32 mmHg
  • white cell count: >12⨉10cells/L, <4⨉10cells/L, or containing >10% band forms



Conditions capable of producing the systemic inflammatory response syndrome include :

History and etymology

The definition of SIRS was agreed during the 1992 meeting of the American College of Chest Physicians and the Society of Critical Care Medicine .