systemic inflammatory response syndrome (SIRS)

Last reviewed 05/2021

Systemic inflammatory response syndrome (SIRS)

  • defined as 2 or more of the following variables:
    • fever of more than 38°C (100.4°F) or less than 36°C (96.8°F)

    • heart rate of more than 90 beats per minute

    • respiratory rate of more than 20 breaths per minute or arterial carbon dioxide tension (PaCO 2) of less than 32 mm Hg

    • abnormal white blood cell count (>12,000/µL or < 4,000/µL or >10% immature [band] forms)

SIRS is nonspecific

  • not always related to infection - can be caused by ischaemia, inflammation, trauma, infection, or several insults combined