Sepsis and Septic Shock Flashcards Preview

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Flashcards in Sepsis and Septic Shock Deck (52)
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1
Q

What is systemic inflammatory response syndrome (SIRS)?

A

Widespread inflammatory response to a variety of clinical insults. This can include things like pancreatitis, burns and trauma

2
Q

What clinical parameters are assessed to determine if someone has SIRS?

A
  • Temperature
  • Heart Rate
  • Respiratory rate
  • WBC count
3
Q

When assessing temperature in the criteria for SIRS, what threshold(s) is/are used?

A
  • >38oC
  • <36oC
4
Q

Whan assessing heart rate in the criteria for SIRS, what HR thershold (s) is/are used?

A

>90bpm

5
Q

When assessing respiratory rate in the criteria for SIRS, what thershold (s) is/are used?

A

>20 breaths/minute

OR

PaCO2 <32

6
Q

When assessing the WBC count in the criteria for SIRS, what threshold(s) is/are used?

A
  • >12000 cells/mm3
  • <4000 cells/mm3
7
Q

What is the definition of sepsis?

A

SIRS plus infection

Life-threatening organ dysfunction caused by dysregulated host repsonse to infection

8
Q

What is the definition of severe sepsis?

A

Sepsis plus End organ damage

9
Q

What is the definiton of septic shock?

A

Severe sepsis plus Hypotension unresponsive to fluids

Can be identified with a clinical construct of sepsis with persisting hypotension requiring vasopressors to maintain MAP >65mmHg and having a serum lactate of >2mmol/l despite adequate volume resuscitation

10
Q

What occurs in phase 1 of sepsis pathophysiology?

A

Release of bacterial toxin

  • Endotoxin - LPS
  • Exotoxin - superantigen
11
Q

What occurs in phase 2 of sepsis pathophysiology?

A

Mediator relsease in response to infection

  • Pro-inflammatory cytokines - cause inflammatory response
  • Anti-inflammatory sytokines - keeps pro-inflammatory response in check
12
Q

What chemical is released in response to vascular endothelial damage caused by infectious organisms?

A

Nitric oxide - chemical vasodilator

13
Q

What pathway is activated by bacterial toxins?

A

Complement pathway - stimulates mast cells

14
Q

What chemical do mast cells release in repsonse to activation by the complement pathway?

A

Histamine

15
Q

What are the main pro-inflammatory cytokines released by macrophages nad neutrophils in response to bacterial toxin release?

A
  • TNF
  • IL-1
16
Q

What chemicals do the endothelial cells release in response to being stimulated by TNF and IL-1?

A

Release of reactive oxygen species and platelet activating factor

17
Q

What is the overall outcome on vascular structure and permeability in response to pro-inflammatory cytokine release?

A
  • Damage and increased permeability
  • Net increase in clotting
18
Q

What are the effects of pro-inflammatory mediators?

A
  • Promote endothelial cell – leukocyte adhesion
  • Release of arachidonic acid metabolites
  • Complement activation
  • Vasodilatation of blood vessels by NO
  • Increase coagulation - release of tissue factors and membrane coagulants
  • Cause hyperthermia
19
Q

What are the effects of anti-inflammatory mediators?

A
  • Inhibit TNF alpha
  • Augment acute phase reaction
  • Inhibit activation of coagulation system
  • Provide negative feedback mechanisms to pro-inflammatory mediators
20
Q

What is the difference between septic shock and immunoparalysis in terms of pro-inflammatory and anti-inflammatory cytokines?

A
  • Septic shock - compensatory mechisms are outweighed by pro-inflammatory mechanisms
  • Immunoparalysis - Compensatory mechanisms outweigh pro-inflammatory mechanisms
21
Q

What is the definiton of septicaemia?

A

Was used to denote the presence of multiplying bacteria in the circulation, but has been replaced with other terms e.g. sepsis, severe sepsis, septic shock

22
Q

What are symptoms of sepsis?

A
  • Fever/Hypothermia
  • Confusion
  • Specific sysmptoms indicative of cause
23
Q

What are signs that someone has sepsis?

A
  • Tachypnoea
  • Tachycardia
  • Increased/decreased temperature
  • Decreased urine output
  • Warm perfused peripheries
  • Bounding pulse
  • Low oxygen saturations
  • Hypotension
  • Mottled skin
  • Sign of specific source of infection
24
Q

What could a bounding pulse with warm peripheries indicate?

A

Sepsis

25
Q

What are risk factors for the development of sepsis?

A
  • Underlying malignancy
  • Age > 65
  • Immunocompromise
  • Haemodialysis
  • Alcoholism
  • Diabetes
  • Recent surgery/breached skin integrity
  • Vascular - indwelling devices/IVDU
  • Pregnancy
26
Q

What organ dysfunction variables would you look at to assess for sepsis?

A
  • Arterial hypoaemia (<50mmHg)
  • Oliguria (<0.5ml/kg/h)
  • Increased creatinine
  • Coagulation abnormalities (PT>1.5, APTT > 60s)
  • Thrombocytopenia
  • Hyperbilirubinaemia
27
Q

What variables could you use to assess tissue perfusion?

A
  • Lactate
  • Skin mottling
  • Reduced capillary perfusion
28
Q

Why is lactate used as a measure of tissue perfusion?

A

If oxygen supply is inadequate, mitochondria are unable to continue ATP synthesis at a rate sufficient to supply cells with ATP. To compensate, glycolysis is increased, and excess pyruvate is converted to lactate by lactate dehydrogenase, and is released into the blood stream

29
Q

How is lactate used once it is produced?

A
  • Oxidation back to pyruvate by well-oxygenated muscle cells, heart cells, and brain cells
  • Conversion to glucose via gluconeogenesis in the liver and release back into circulation
30
Q

What changes in blood sugar can occur in sepsis?

A

Hyperglycaemia >8mmol/L

31
Q

What investigations would you do if you suspected someone had sepsis as part of the sepsis 6 protocol?

A
  • Blood lactate and FBC
  • Blood cultures
  • Urine output
32
Q

What investigations would you do to assess a source of infection in suspected sepsis?

A
  • Examination - anywounds/surgery
  • CXR/sputum
  • Urinalysis/culture
  • Swab sample - prosthetic, epidural
  • Lumbar puncture
  • Echo - vegitations
  • Pleural fluid culture
  • Peritoneal fluid culture
33
Q

What bloods would you do if you suspected someone had sepsis?

A
  • FBC with differential white count
  • U+E’s, serum creatinine
  • LFT
  • Glucose
  • Lactate
  • CRP
  • Blood cultures
  • ABG
34
Q

How much does the risk of mortality increase by per hour of delay of antibiotic adminstration to someone who is septic?

A

7.6% per hour

35
Q

Why would you do U+Es in someone with suspected sepsis?

A

Electrolytes frequently deranged

36
Q

Why would you do FBC with differential white count in sepsis?

A
  • Low platelets
  • Deranged white cells (can be one of following):
    • WBC count >12×10^9/L (12,000/microlitre) (leukocytosis)
    • WBC count <4×10^9/L (4000/microlitre) (leukopenia)
    • Normal WBC count with >10% immature forms
37
Q

Why would you do LFTs in sepsis investigation?

A

Determine liver function

  • Elevated bilirubin
  • Elevated ALT/AST, Alk phos and gamma-T
38
Q

Why would you ask for a serum lactate in someone with suspected sepsis?

A

To evaluate tissue perfusion - Persistently elevated lactate levels may parallel the degree of malperfusion or organ failure.

  • Levels >2 mmol/L (>18 mg/dL) associated with adverse prognosis
  • Even worse prognosis with levels >4 mmol/L (>36 mg/dL)
39
Q

Why would you perform an ABG in someone with suspected sepsis?

A

ABG evaluation facilitates optimisation of oxygenation, and is indicative of metabolic status (acid-base balance).

Lactate levels are most reliably assessed using an ABG sample. However, in practice, a venous blood gas (VBG) sample is often used

Most patients do not undergo ABG sampling unless there is a respiratory component.

PaCO2 <4.3 kPa (32 mmHg) is one of the diagnostic criteria for SIRS

40
Q

What is the best way to obtain a serum lactate?

A

ABG

41
Q

Why would you take a serum glucose in someone that is septic?

A

Marker for stress

May be elevated, with or without known history of diabetes, due to the stress response and to altered glucose metabolism.

Can be low - acute liver failure

42
Q

Why would you take a serum creatinine in someone that is septic?

A

To assess renal dysfunction

43
Q

What is important to remember about the white cell count when used to assess sepsis?

A

It is sensitive but not specific for sepsis. Can also be changed by non-infectious injury, cancer, and immunosuppressive agents

44
Q

Why would you take a CRP in someone that is septic?

A

Baseline marker for inflammation - can map its progress through treatment

45
Q

When taking blood cultures, what is important to remember?

A

Take BEFORE administration of antibiotics

46
Q

What are the three aspects of the sepsis 6 that are to do with management of a patient with sepsis?

A
  • IV antibiotics - within 1 hour
  • Oxygen - aim 94-98%
  • IV fluid - minimum 500ml
47
Q

If a septic patient was not responding to fluid challenge, how would you maintain their BP, and what threshold would you aim for?

A

Vasopressors - >65mmHg

48
Q

When would you consider moving to HDU?

A

If evidence of severe sepsis:

  • Low BP responsive to fluids
  • Lactate >2
  • Elevated creatinine
  • Oliguria
  • Liver dysfunction, Bil, PT, Plt
  • Bilateral infiltates, hypoxaemia
49
Q

When would you consider moving to ITU?

A

Evidence of Septic shock

  • Multi-organ failure
  • Requires sedation, intubation and ventilation
50
Q

What can cause SIRS?

A
  • Trauma
  • Burns
  • Pancreatitis
  • Ischaemia
  • Haemorrhage
51
Q

What is the SOFA?

A

Sequential organ failure assessment

52
Q

What are the different criteria assessed in the qSOFA?

A
  • BP <100
  • RR >22
  • GCS < 15