From the Guidelines
To fulfill the criteria for Systemic Inflammatory Response Syndrome (SIRS) in this patient, you would need to find either tachycardia (heart rate >90 beats per minute), tachypnea (respiratory rate >20 breaths per minute or PaCO2 <32 mmHg), or an abnormal white blood cell count (>12,000/mm³, <4,000/mm³, or >10% immature bands). Given the patient's presentation with fever (temperature of 101.1°F or 38.4°C), which already meets one criterion for SIRS, identifying any of the other parameters would complete the SIRS diagnosis. The patient's heart rate of 88 bpm does not meet the criterion for tachycardia as defined by a heart rate >90 beats/min 1. However, the patient's respiratory rate of 20/min meets the criterion for tachypnea, which is a respiratory rate >20 breaths/min 1. Additionally, the patient's WBC count of 13,000/µL with 12% bands also meets the criterion for an abnormal white blood cell count, as it exceeds 12,000/mm³ and includes >10% immature (band) forms 1. Therefore, the findings that would help fulfill the criteria for SIRS in this patient include the respiratory rate of 20/min and the WBC count of 13,000/µL with 12% bands. It is crucial to diagnose SIRS promptly because it can progress to sepsis if an infection is present, necessitating immediate intervention with antibiotics and supportive care to prevent further deterioration to septic shock and multiple organ dysfunction syndrome. Key points to consider in the diagnosis of SIRS include:
- Temperature >38°C or <36°C
- Heart rate >90 beats/min
- Respiratory rate >20 breaths/min or PaCO2 <32 mmHg
- White blood cell count >12,000/mm³ or <4,000/mm³ or >10% immature bands, as outlined in the criteria for SIRS 1.
From the Research
Systemic Inflammatory Response Syndrome (SIRS) Criteria
To fulfill the criteria for SIRS in a patient with fever, hypotension, and altered mental status, the following findings would be relevant:
- A heart rate of more than 90 bpm, as tachycardia is one of the criteria for SIRS 2, 3
- A respiratory rate of more than 20 breaths per minute, as tachypnea is another criterion for SIRS 2, 3
- A white blood cell (WBC) count of more than 12,000 cells/μL or less than 4,000 cells/μL, as leukocytosis or leukopenia is a criterion for SIRS 3, 4
- More than 10% immature neutrophils (bands), as this is also a criterion for SIRS 3, 4
Relevant Findings in the Patient
Given the patient's presentation, the following findings would help fulfill the criteria for SIRS:
- A WBC count of 13,000/µL with 76% neutrophils, 10% lymphocytes, and 12% bands, which meets the criterion for leukocytosis and increased immature neutrophils 3, 4
- A respiratory rate of 20/min, which meets the criterion for tachypnea 2, 3 Note that a heart rate of 88 bpm is not significantly elevated and would not meet the criterion for tachycardia 2, 3.
Other Findings
Other findings such as kidney dysfunction with creatinine of 3.8 mg/dL and urine output of 450 mL/day, and lactic acid of 3.8 mmol/L, are indicative of organ dysfunction and may be relevant in the diagnosis of sepsis or severe sepsis, but are not specific criteria for SIRS 3, 5.