Septic Shock - Definition

Definition

In humans, septic shock has a specific definition requiring several conditions to be met for diagnosis:

• First, SIRS (systemic inflammatory response syndrome) must be diagnosed by finding at least any two of the following:

Tachypnea (high respiratory rate) > 20 breaths per minute, or on blood gas, a PCO2 less than 32 mmHg signifying hyperventilation.

White blood cell count either significantly low, < 4000 cells/mm³ or elevated > 12000 cells/mm³.

Heart rate > 90 beats per minute

Temperature: Fever > 38.5 °C (101.3 °F) or hypothermia < 35.0 °C (95.0 °F)

• Second, there must be sepsis and not an alternative form cause of SIRS. Sepsis requires evidence of infection, which may include positive blood culture, signs of pneumonia on chest x-ray, or other radiologic or laboratory evidence of infection.
• Third, signs of end-organ dysfunction are required such as renal failure, liver dysfunction, changes in mental status, or elevated serum lactate.
• Finally, septic shock is diagnosed if there is refractory hypotension (low blood pressure that does not respond to treatment). This signifies that intravenous fluid administration alone is insufficient to maintain a patient's blood pressure from becoming hypotensive.