In SIRS, which of the following is true about the pattern of mediators, vascular tone, vascular permeability, and myocardial function?

• A. Decreased inflammatory mediators; vasoconstriction; decreased vascular permeability; myocardial excitation
• B. Increased inflammatory mediators; vasodilation; increased vascular permeability; myocardial depression
• C. Increased inflammatory mediators; vasoconstriction; decreased vascular permeability; myocardial depression
• D. Decreased inflammatory mediators; vasodilation; increased vascular permeability; myocardial depression

Answer: (B)

Systemic inflammatory response syndrome involves a surge of inflammatory mediators that provoke widespread changes in the circulation and heart. The inflammatory mediators, such as cytokines, cause vasodilation and make capillaries more permeable. Vasodilation lowers systemic vascular resistance and helps drive hypotension, while increased vascular permeability leads to fluid leakage into the interstitial space, contributing to relative hypovolemia. The same inflammatory milieu also depresses myocardial contractility, reducing the heart's pumping ability. Putting that together, the pattern is increased inflammatory mediators with vasodilation, increased vascular permeability, and myocardial depression. The other patterns don’t fit: they either imply vasoconstriction, decreased permeability, or decreased mediators, which contradict what occurs in SIRS/sepsis.