1. SIRS and MODS

2. SIRS
Systemic inflammatory response syndrome (SIRS) is a systemic inflammatory response to a variety of insults.
Generalized inflammation in organs remote from the initial insult
Insults resulting in SIRS include infection (referred to as sepsis), ischemia, infarction, and injury (see Table 67-5).

3. SIRS
Triggers
Mechanical tissue trauma: burns, crush injuries, surgical procedures
Abscess formation: intraabdominal, extremities
Ischemic or necrotic tissue: pancreatitis, vascular disease, myocardial infarction

4. SIRS Triggers Microbial invasion: bacteria, viruses, fungi
Endotoxin release: gram-negative bacteria
Global perfusion deficits: post–cardiac resuscitation, shock states
Regional perfusion deficits: distal perfusion deficits
The inflammatory response can be triggered by any event, but it is most often associated with a bacterial infection. The events most often associated with the development of SIRS and MODS are shock, trauma, burns, aspiration, venomous snakebites, cardiac arrest, thromboemboli, myocardial infarction, operative procedures, vascular injury, infection, pancreatitis, and disseminated intravascular coagulation (DIC).

5. MODS
Multiple organ dysfunction syndrome (MODS) is the failure of two or more organ systems.
Homeostasis cannot be maintained without intervention.
Results from SIRS
Mortality rates are linearly related to the number of failed organ systems
These two syndromes represent the ends of a continuum. Transition from SIRS to MODS does not occur in a clear-cut manner.
The usual sequence of MODS depends somewhat on its cause but often begins with pulmonary failure 2 to 3 days after surgery, followed, in order, by hepatic failure, stress-induced gastrointestinal (GI) bleeding, and renal failure.
Patients with two or more organ systems involved have a mortality rate of approximately 75%, and patients with four organ systems involved have a 100% mortality rate

6. MODS Stage 1 Stage 2 Stage 3 Stage 4 Increased volume requirements
Mild respiratory alkalosis which is accompanied by oliguria, hyperglycemia and insulin requirements.
Stage 2
Tachypneic, hypocapnic and hypoxemic.
Moderate liver dysfunction
Possible hematologic abnormalities.
Stage 3
Shock with BUN/creatine, acid-base disturbances.
Significant coagulation abnormalities.
Stage 4
Vasopressor dependent and UO.
Ischemic colitis and lactic acidosis follow.

8. Relationship of Shock, SIRS, and MODS8

9. SIRS and MODS Pathophysiology
Consequences of inflammatory response
Release of mediators
Direct damage to the endothelium
Hypermetabolism
Vasodilation leading to decreased SVR
Increase in vascular permeability
Activation of coagulation cascade

10. SIRS and MODS Pathophysiology
Organ and metabolic dysfunction
Hypotension
Decreased perfusion
Formation of microemboli
Redistribution or shunting of blood

11. SIRS and MODS Pathophysiology
Respiratory system
Alveolar edema
Decrease in surfactant
Increase in shunt
V/Q mismatch
End result: ARDS
The respiratory system is often the first system to show signs of dysfunction in SIRS and MODS.
Patients with ARDS require aggressive pulmonary management with mechanical ventilation.

12. SIRS and MODS Pathophysiology
Cardiovascular system
Myocardial depression and massive vasodilation
The baroreceptor reflex causes release of inotropic (increasing force of contraction) and chronotropic (increasing heart rate) factors that enhance CO.
To compensate for hypotension, CO increases with an increase in heart rate and stroke volume.

13. SIRS and MODS Pathophysiology
Neurologic system
Mental status changes due to hypoxemia, inflammatory mediators, or impaired perfusion
Often early sign of MODS
The patient may become confused and agitated, combative, disoriented, lethargic, or comatose.

14. SIRS and MODS Pathophysiology
Renal system
Acute renal failure
Hypo-perfusion
Release of mediators
Activation of renin-angiotensin- aldosterone system
Nephrotoxic drugs, especially antibiotics
Careful monitoring of drug levels is essential to avoid the nephrotoxic effects.

15. SIRS and MODS Pathophysiology
GI system
Motility decreased: abdominal distention and paralytic ileus
Decreased perfusion: risk for ulceration and GI bleeding
Potential for bacterial translocation
In the early stages of SIRS and MODS, blood is shunted away from the GI mucosa, making it highly vulnerable to ischemic injury.

16. SIRS and MODS Pathophysiology
Hypermetabolic state
Hyperglycemia-hypoglycemia
Insulin resistance
Catabolic state
Liver dysfunction
Lactic acidosis
Glycogen stores are rapidly converted to glucose (glycogenolysis).
Once glycogen is depleted, amino acids are converted to glucose (gluconeogenesis), reducing protein stores.
Fatty acids are mobilized for fuel.
Catecholamines and glucocorticoids are released, resulting in hyperglycemia and insulin resistance.
The net result is a catabolic state, and lean body mass (muscle) is lost.

17. SIRS and MODS Pathophysiology
Hematologic system
DIC
Electrolyte imbalances
Metabolic acidosis
DIC results in simultaneous microvascular clotting and bleeding caused by depletion of clotting factors and platelets, combined with excessive fibrinolysis.

18. SIRS and MODS Collaborative Care
Prognosis for MODS is poor.
Goal: prevent the progression of SIRS to MODS
Vigilant assessment and ongoing monitoring to detect early signs of deterioration or organ dysfunction are critical.
MOD mortality rates are 70% to 80% when three or more organ systems fail.
Survival improves with early, goal-directed therapy. (An example of a Sepsis Alert Protocol [eFig. 67-1] is available on the Evolve website for this chapter.)
Collaborative care for patients with MODS focuses on (1) prevention and treatment of infection, (2) maintenance of tissue oxygenation, (3) nutritional and metabolic support, and (4) appropriate support of individual failing organs.
Table summarizes management for patients with MODS.

19. SIRS and MODS Collaborative Care
Prevention and treatment of infection
Aggressive infection control strategies to decrease risk for nosocomial infection
Once an infection is suspected, institute interventions to control the source.
Early, aggressive surgery is recommended to remove necrotic tissue (e.g., early debridement of burn tissue) that may provide a culture medium for microorganisms.
Aggressive pulmonary management, including early ambulation, can reduce the risk of infection.
Strict asepsis can decrease infections related to intraarterial lines, endotracheal tubes, urinary catheters, IV lines, and other invasive devices or procedures.

20. SIRS and MODS Collaborative Care
Maintenance of tissue oxygenation
Decreased O2 demand
Sedation
Mechanical ventilation
Paralysis
Analgesia
These patients have greater oxygen needs and decreased oxygen supply to the tissues.
Oxygen delivery may be optimized by maintaining normal levels of hemoglobin (e.g., transfusion of packed RBCs) and PaO2 (80 to 100 mm Hg), using individualized tidal volumes with positive end-expiratory pressure, increasing preload (e.g., fluids) or myocardial contractility to enhance CO, or reducing afterload to increase CO.

21. SIRS and MODS Collaborative Care
Nutritional and metabolic needs
Goal of nutritional support: preserve organ function
Total energy expenditure is often increased 1.5 to 2.0 times.
Protein-calorie malnutrition is one of the primary manifestations of hypermetabolism and MODS.
Because of their relatively short half-life, the nurse should monitor plasma transferrin and prealbumin levels to assess hepatic protein synthesis.

22. SIRS and MODS Collaborative Care
Nutritional and metabolic needs
Use of the enteral route is preferred to parenteral nutrition.
Monitor plasma transferrin and prealbumin levels to assess hepatic protein synthesis.
The goal of nutritional support is to preserve organ function.
Providing early and optimal nutrition decreases morbidity and mortality rates in patients with SIRS and MODS.

23. SIRS and MODS Collaborative Care
Support of failing organs
ARDS: aggressive O2 therapy and mechanical ventilation
DIC: appropriate blood products
Renal failure: continuous renal replacement therapy or dialysis
Continuous renal replacement therapy is better tolerated than hemodialysis, especially in a patient with hemodynamic instability.

24. SIRS and MODS Nursing Management
Reduce chance of infection
Dressing changes on all invasive line sites and surgical wounds according to protocol
Maintain aseptic technique with all dressing changes and manipulation of intravenous lines.
Institute the measures that are necessary to prevent aspiration when patients are placed on enteral feedings.
Keep the head of the bed elevated, and check for residual volume and tube placement every 4 hours
Oral care if on ventilator

25. SIRS and MODS Nursing Management
Provide frequent rest periods
Create a quiet environment whenever possible.
Schedule procedures and nursing care interventions so that the patient has periods of uninterrupted rest.
Manage situations of increased metabolic demand— such as fever, agitation, alcohol withdrawal, and pain—promptly so that the patient conserves energy and limits oxygen consumption.
Monitor bony prominences and areas of high risk for skin breakdown.