Which vascular change is characteristic of SIRS?

• A. Vasoconstriction
• B. Vasodilation
• C. No change
• D. Spasm

Answer: (B)

Vasodilation is the vascular change seen in SIRS. When the body mounts a systemic inflammatory response, inflammatory mediators such as nitric oxide, histamine, and prostaglandins cause widespread relaxation of vascular smooth muscle. This leads to dilation of arteries and arterioles, reducing systemic vascular resistance and often causing hypotension with signs of warm, flushed skin early in the course. Vasoconstriction, no change, or spasms would not reflect this global vasodilatory pattern typical of SIRS.