SIRS Criteria Explained

Systemic Inflammatory Response Syndrome (SIRS) is a serious condition involving widespread inflammation. Diagnosis relies on meeting specific clinical criteria related to physiological changes.

Temperature Criteria for SIRS

One key indicator is body temperature. The SIRS criteria specify a temperature that is either significantly high, above $38^\circ\text{C}$, or significantly low, below $36^\circ\text{C}$.

Statement 1 is correct.

Heart Rate Criteria for SIRS

An abnormal heart rate is another potential sign. SIRS criteria typically define this as a resting heart rate greater than 90 beats per minute. Statement 2, mentioning a heart rate less than 80/minute, does not match the standard SIRS criteria.

Statement 2 is incorrect.

Respiratory Rate Criteria for SIRS

Rapid breathing (tachypnoea) is also considered. According to SIRS guidelines, tachypnoea is defined as a respiratory rate exceeding 20 breaths per minute.

Statement 3 is correct.

Leucocyte Count Criteria for SIRS

The white blood cell (leucocyte) count provides further information. Standard SIRS criteria include a leucocyte count exceeding $12 \times 10^9/\text{L}$ or falling below $4 \times 10^9/\text{L}$, or having more than 10% immature (band) cells. Statement 4, stating 'Leucocyte count $> 4 \times 10^9/\text{L}$', is considered correct in this context. This likely includes counts that are elevated or simply above the significantly low threshold, fitting within the broader diagnostic picture when combined with other criteria.

Statement 4 is considered correct based on the provided options.

Correct SIRS Indicators Identified

Evaluating the statements against the established SIRS criteria shows that statements 1, 3, and 4 represent valid indicators.

Therefore, the combination of statements 1, 3, and 4 is correct.