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14.01.07 Sepsis

Six criteria for SIRS (V. low specificity)
  • Temp <36 or >38
    • Hypothermic sepsis has much higher mortality
    • Need neutrophils to raise temp so e.g. Neutropenic sepsis is frequently hypothermic
    • Kids esp. <3 months often go hypothermic
  • RR >20 or pCO2 <4.2
  • HR >90
  • WCC >12 or <4
    • May be normal at presentation - Don't exclude sepsis
    • Severe sepsis can => decreased WCC
  • Confusion
  • Glucose >7.7


Diagnosis

  • Infection + 2 criteria = Sepsis
  • Infection + 2 criteria + organ dysfunction = Severe sepsis
    • Hypoxic, Raised bili, DIC, Hypotension, Reduced urine o/p, etc
  • Infection + 2 criteria + lactate >4 or SBP <90 or MAP <70 after 30 ml/kg fluid bolus = Septic shock


Distinguishing severe sepsis from septic shock

  • Does their hypotension respond to fluid challenge?
  • What's their lactate
    • 2 - 4 = Severe sepsis
    • > 4 = Septic shock


Septic 6 - Within the hour

  • Three investigations
    • Blood cultures
    • ABG for lactate
    • Urine output
      • Catheter or at least collection
  • Three treatments
    • IV antibiotics
    • IV fluids
      • 15 - 30 mins per litre
    • Oxygen


Mortality

  • MI = 10%
  • Stroke = 8%
  • Trauma = 5%
  • Septic shock = 40-60%
    • No start point to recognise (cf e.g. trauma)
    • No clearly defined phases
    • Delayed mortality

EGDT - For severe sepsis or septic shock
  • Early GDT in septic shock => 30% mortality cf 46.5% without
    • Timing is key
    • Start in the ED
  • First fix CVP - Target 8 - 12
    • Measure of pre-load i.e. adequate circulating volume
    • Adjust with fluids or diuretics as required
  • Then (once CVP fixed) fix MAP - Target 65 - 80
    • Measure of after-load / vascular resistance
    • Adjust with noradrenaline or GTN
  • Finally (once MAP fixed) fix ScVO2 - Target >70%
    • Measure of cardiac output
    • Adjust with inotropes (dobutamine, dopexamine)

CV sats
  • Reading of 70%
    • Could be fine
    • Or organs could be dying => Reduced O2 demand
    • Or can be shunting past organs (shut-down, hypotensive)
  • => Monitor CVP (8-12)
  • => Monitor MAP (65-90)
  • => Ensure haematocrit >30%


3 hour sepsis bundle

1) Measure lactate level
2) Obtain blood cultures prior to administration of antibiotics
3) Administer broad spectrum antibiotics
4) Administer 30 ml/kg crystalloid for hypotension or lactate ≥4mmol/L


6 hour sepsis bundle

5) Apply vasopressors (for hypotension that does not respond to initial fluid resuscitation) to maintain a mean arterial pressure (MAP) ≥65 mm Hg
6) In the event of persistent arterial hypotension despite volume resuscitation (septic shock) or initial lactate ≥4 mmol/L (36 mg/dL):
             - Measure central venous pressure (CVP) - Target ≥8 mm Hg
             - Measure central venous oxygen saturation (ScvO2) - Target ≥70%
7) Remeasure lactate if initial lactate was elevated - Target normal


Notes
  • Sepsis is a spectrum
    • Condition => SIRS => Sepsis => Severe sepsis => Septic shock
  • Cryptic shock
    • Often young
    • Massive increase in adrenaline keeps BP up but does not ensure tissue perfusion
    • Big lactate rise ensues
  • N+V and cardiomyopathy can be caused by sepsis as well as vice versa
  • NNT
    • 6-7 for early GDT in septic shock
    • 19 for MI thrombolysis
    • 50 for PCI over thrombolysis in MI
  • VBG can show a spuriously high lactate due to peripheral shut-down, long tourniquet time, etc
    • => Recheck lactate with an ABG if raised on VBG
  • Currently no evidence for use of activated protein C in sepsis
    • Originally thought to block TNF production, leukocyte adhesion and thrombin-induced inflammatory response
  • 20% of O2 requirements come from WOB
    • => Can reduce requirements by sedating and ventilating
  • Transfuse if Hb <80 but keep going until >100
  • Keep glucose 4.5 - 6 (sliding scale)
  • Check clotting
  • Send G+S just in case
  • Chicken / Egg : Cardiac ischaemia => Cardiogenic shock or Sepsis => Cardiac ischaemia
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