case 89 - sepsis and multisystem organ dysfunction syndrome

Question 1

distinguish among SIRS, Sepsis, severe sepsis, septic shock, MODS

Answer 1

SIRS

• HR > 90
• RR > 20 or PaCo2 < 30 mm Hg
• Temp > 38 or < 36
• WBC > 12k or < 4k

Sepsis:

• SIRS + documented infection

Severe Sepsis:

• sepsis + organ dysfunction

Septic shock:

• sepsis + organ dysfunction + hypotension unresponsive to fluids and pressors

MODS

• dysfunction of two or more systems that intervention is needed to maintain homeostasis

Question 2

What is the pathophysiology of sepsis-related organ dysfunction?

Answer 2

Sepsis

• result of an initial infectious insult
• immune response activiated –> hyperactive immune system –> systemic release of inflammatory mediators (cytokines, IL’s, TNF-alpha)
  
  • inflammatory mediators result in isolating bacteria; however, also destroy the body.

gut translocation theory of sepsis

• possible that hypoperfusion of gut leads to disruption of gastrointestinal mucosa –> translocation of normal endogenous gut flora into systemic circulation
• second insult of sepsis –> worse outcomes

Question 3

how does sepsis cause organ dysfunction (Heart, Lung, Liver, Kidney)

Answer 3

Heart

• Hypotension
  
  • inflammatory mediator associated with increased levels of Nitric oxide produciton (via endothelial cells) + dec levels of vasopressin
• decrease SVR and venodilation
  
  • hyperdynamic, high CO (compensatory mech to maintain BP)
  • eventually leads to systolic and diastolic dysfunction
• pulm HTN –> RV failure

Lung

• ARDS or ALI
  
  • inflamm mediators destroy endothelial cells in lung –> neutrophils infiltrate lung parenchyma and alveolar spaces -> exudate pulm edema
  • v/q mismatch, shunt, impaired gas diffusion, atelectasis
• increase PVR -> Pulm HTN -> RV failure

Kidney

• AKI
  
  • systemic vasodilation and hypotension leads to dec RBF
  • endothelial cell injury –> thrombosis
  • RIFLE criteria

Liver

• Shock liver
  
  • systemic vasodilation and hypotension leads to dec liver blood flow
  • elevated LFTs, decrease synthetic funciton –> hypoalbuminemia and coagulopathy

Question 4

how does sepsis cause organ dysfunction (Heme, CNS)

Answer 4

HEME

• direct bone marrow suppresion
  
  • anemia, immunosupressed state
  • luekopenia = neg prognostic sign
  • thrombocytopenia
  • at risk for additional infections
• DIC
  
  • activation of inflamm mediators result in consumptive coagulopathy
  • liver dysfunction due to shock liver

CNS

• encephalopathy
  
  • liver dysfucntion –> hyperammonia levels
• cerbreal ischemia
  
  • hypoperfusion during shock state
• myoneuopathy
  
  • hypoperfusion and cytokine damage of nerves

Question 5

How will you treat sepsis and MODS?

Answer 5

4 GOALS:

1) control infection

• immediate broad-spec abx (gram neg, gram pos coverage)
  
  • never delay abx therapy
• source control
  
  • urine, blood, sputum culture
  • CXR, CT - > find source of infection
  • infected tissue? infected hardware? perc drainage?

2)resusciation and maintenance of organ perfusion

• early aggressive resuscitation to specific end goals (Svo2, MAP, CVP, UOP)
• fluid admin to CVP of 12
• maintain MAP > 65 with vasopressors (norepi, vaso)
• SVO2 > 70
  
  • SVo2 < 70 + hgb < 7 -> PRBC
  • SVo2 < 70 + hgb > 7 -> inotrope (epi/dobut)

3) prophylaxis to prevent complicatoins

• GI ulcers
  
  • hypotension, gut hypoperfusion, dec defense against gastric acidity
  • PPI, H2 blockers
• DVT
  
  • hypercoagulabe state 2/2 proinflam cytokine
  • unfraction or LMWH
• VAP
  
  • semirecumbent position (prevent microaspir)
  • spont breathig trials, sedation interruption (lessen mech vent duration

4) support and replacement or organ function

• lung protect stratetgy for ALI/ARDS
  
  • TV 4-6 cc/kg + Pplat < 30 cm h2o
  • increase PEEP, recruit maneuvers
• RRT
  
  • AEIOU: acidosis, electrolyte, intoxication, overload (fluid), uremia

Question 6

How is catheter-related sepsis prevented?

Answer 6

Prevention of catheter-related infection

• adhere to checklists and use of standard protocols
• staf education and training (sterility of catheters)
• use of catheter materials and coatings that reduce bacterial adhesion and grwoth
• preference of subclavian vein over other sites
• good hand hygeine
• chlorhexidine-alcohol prepration solution
• removal of catheter when not needed