Which finding is a SIRS criterion?

Which finding is a SIRS criterion?

• A. Heart rate greater than 90 beats per minute
• B. PaCO2 greater than 40 mmHg
• C. WBC count between 4,000 and 12,000/mm³
• D. Temperature 37.0 C to 37.5 C

Answer: (A)

SIRS is identified when two or more systemic inflammatory criteria are present. These include tachycardia (heart rate >90 bpm), tachypnea or low PaCO2, fever or hypothermia, and abnormal white blood cell counts. The finding of a heart rate greater than 90 bpm fits the tachycardia criterion, which is why it is the correct choice. The other options don’t meet SIRS criteria: PaCO2 greater than 40 mmHg is not a SIRS criterion (the relevant threshold is PaCO2 <32 mmHg); a WBC count between 4,000 and 12,000/mm³ is a normal range, not an abnormal WBC criterion; and a temperature of 37.0–37.5°C is within normal limits, not fever or hypothermia.

SIRS is identified when two or more systemic inflammatory criteria are present. These include tachycardia (heart rate >90 bpm), tachypnea or low PaCO2, fever or hypothermia, and abnormal white blood cell counts. The finding of a heart rate greater than 90 bpm fits the tachycardia criterion, which is why it is the correct choice. The other options don’t meet SIRS criteria: PaCO2 greater than 40 mmHg is not a SIRS criterion (the relevant threshold is PaCO2 <32 mmHg); a WBC count between 4,000 and 12,000/mm³ is a normal range, not an abnormal WBC criterion; and a temperature of 37.0–37.5°C is within normal limits, not fever or hypothermia.