SIRS: Systemic Inflammatory Response Syndrome

• SIRS (Systemic Inflammatory Response Syndrome) is triggered by acute stress, leading to organ dysfunction due to a dysregulated host response.
• Causes of SIRS include surgery, infection, medication reactions, burns, acute pancreatitis/aspiration, bacterial/viral infections, toxic shock syndrome, inflammation, malignancy, ischemia, or reperfusion.
• SIRS can result from infectious or non-infectious causes like tissue injury.

SIRS, Sepsis, and Infection

• Sepsis arises when an infection triggers the systemic inflammatory response, releasing cytokines and disrupting homeostasis.
• The inflammatory cascade activation in sepsis leads to inadequate perfusion and organ failure.
• SIRS is an amplified defense response to stressors, which aims to localize and remove the stressor's source.
• SIRS can be a critical condition stemming from injury or infection, potentially causing organ failure and death.
• The triggers of inflammation in SIRS include non-infectious or infectious stimuli which then activate the cellular and humoral immune responses, the complement pathway, and cytokines.
• SIRS occurs when the balance between inflammatory and anti-inflammatory responses shifts toward inflammation.
• A subsequent deregulated cytokine storm results in a massive inflammatory response and possible organ dysfunction or death.
• Liver dysfunction, a major consequence of SIRS, can lead to cerebral edema, blood clotting issues, and renal failure.
• Sepsis is suspected when a SIRS response occurs alongside a suspected infection.
• Severe sepsis is diagnosed when sepsis is accompanied by one or more organ failures. Septic shock is diagnosed. when hemodynamic instability continues despite intravascular volume replacement. Inflammatory and anti-inflammatory bodily responses progressively worsen

SIRS vs. Sepsis

• Most septic patients have SIRS, but not all SIRS patients are septic.

Clinical Manifestations

• Common clinical signs include temperature above 38°C (100.4°F), tachycardia, tachypnea, and leukocytosis (above 12,000) or leukopenia (below 4,000).
• The continuous presence of these clinical criteria, along with supporting lab findings, differentiates SIRS from other inflammatory conditions.
• Clients with infectious SIRS (sepsis) may present with low temperature, weakness, and chills.
• Additional manifestations depend on the location and type of the initial infection.
• As sepsis progresses, clients may exhibit decreased consciousness, flushed/warm skin, oliguria, hypotension, and confusion.
• Clients with SIRS usually need critical care because of the severity of manifestations.

Nursing Considerations

• Clients who have SIRS have a higher acuity, and the nurse must utilize astute assessment skills to recognize subtle to overt changes in the client’s condition to prevent clinical deterioration.
• Early identification is crucial for better outcomes.
• More SIRS criteria leads to higher chances of developing MODS, longer ICU stays, increased need for mechanical ventilation and vasopressor support, and blood product transfusions.
• Manifestations possibly indicating progression to sepsis include: acute confusion, SBP < 90 or a decrease of 40+ from baseline, RR > 25, HR > 130, decreased LOC, needing O2 to maintain SpO2 ≥ 92%, mottled/ashen/cyanotic skin, lactate > 2 mmol/L, or anuria for 18 hours or urine output < 0.5 mL/kg/hr.

Treatment

• SIRS treatment aims to prevent progression to shock and MODS, with hemodynamic stability being key.
• Interventions include:
  • IV isotonic fluids (NS) at 30 mL/kg
  • Broad-spectrum antibiotics (after obtaining cultures) and antivirals (during flu season)
  • Vasoconstrictors (e.g., norepinephrine)
  • Anti-inflammatories (e.g., corticosteroids).
  • Oxygen therapy and possible mechanical ventilation.
  • Surgical interventions for abscess drainage or necrotic tissue removal.
  • Glucose control via IV insulin therapy (target: 80-110 mg/dL).

Systemic Inflammatory Response Syndrome (SIRS) occurs due to acute stress, causing organ dysfunction. Sepsis develops when an infection induces a systemic inflammatory response, releasing cytokines. SIRS can result from infectious or non-infectious causes, potentially leading to organ failure and death.