Sepsis

Question 1

What is sepsis?

Answer 1

A systemic inflammatory response which occurs as a result of suspected or confirmed infection.

Question 2

What is the continuum of dysfunction- starting at a systemic inflammatory response?

Answer 2

Sepsis
Severe sepsis
Septic shock

Question 3

What type of shock is sepsis?

Answer 3

Combination of distributive, hypovolaemic and cardiogenic shock

Question 4

What infections can cause sepsis?

Answer 4

-Blood stream infections such as bacteraemia, fungi, parasites and viruses i.e. meningococcal/aspergillus/malaria/cmv
-Pneumonia/respiratory infections

Question 5

Why does systemic vascular resistance become low?

Answer 5

Due to vasodilation

Question 6

What are the effects of vasodilation?

Answer 6

Leads to inadequate perfusion pressure to the capillaries so nutrients and oxygen cannot be pushed across cell walls

Question 7

What is the effect of an increased inflammatory response?

Answer 7

Higher oxygen demand and consumption leading to hypoxia

Question 8

What affects cell metabolism?

Answer 8

Toxic and inflammatory chemical disruption leading to impaired O2 use by cells. Therefore the cellular demand for O2 increases as tissue perfusion increases

Question 9

What causes slow diffusion across capillary membranes?

Answer 9

Decreased blood flow in the capillary beds because of reduced circulating volume and increased blood viscosity. This leads to micro clot formation and activation of the clotting cascade

Question 10

What is Disseminated Intravascular Coagulation?

Answer 10

It is a serious clotting disorder that can lead to uncontrollable bleeding and can be activated by the inflammatory response

Question 11

What are the 4 main elements of pathophysiology ?

Answer 11

Increased vascular permeability and capillary leak
Pathological vasoconstriction and vasodilation
Myocardial dysfunction
Impaired organ perfusion

Question 12

What happens to capillaries during sepsis?

Answer 12

There is a major change in permeability properties of endothelium in all vascular beds. This causes leaking of albumin and water and electrolytes (hypovolaemia)

Question 13

How does sepsis effect vasoconstriction and vasodilation?

Answer 13

Compensatory vasoconstriction takes place as a protective mechanism to maintain tissue and organ perfusion in face of diminished cardiac output

Question 14

What is ‘warm shock’?

Answer 14

Follows fluid resuscitation- leads to bounding pulses, warm peripheries but severe hypotension, acidosis and organ impairment

Question 15

How does sepsis lead to myocardial dysfunction?

Answer 15

Hypovolaemia is a major contributor as it causes a lower circulating volume. As a result there is poor myocardial contractility. There may also be a link to proinflammatory mediators released in sepsis

Question 16

What else may reduce cardiac function?

Answer 16

Hypoxia, acidosis, hypoglycaemia, hypokalaemia, hypocalcaemia and hypophosphataemia

Question 17

What processes lead to impaired organ perfusion?

Answer 17

Renal dysfunction
Pulmonary involvement
Gastrointestinal consequences
CNS involvement in septic shock

Question 18

Summarise the events in sepsis pathophysiology

Answer 18

-Bacteraemia enters the blood
-Release of pro-inflammatory cytokines such as tumor necrosis factor-alpha, IL1 alpha and beta and IL6
-Activation of the complement system, coagulation system, kinin system and neutrophil, endothelial and monocyte-macrophage cell activity
-This leads to the release of anti-inflammatory cytokines
-Resulting in endothelial cell dysfunction such as:
o Capillary Leak
o Microvascular thrombus
o Cell adhesion
o Tissue hypoxia
o Apoptosis
o Impaired vascular tone
o Free radical damage
- As a consequence there is multiple organ dysfunction

Question 19

What are the treatments for sepsis?

Answer 19

Aim to optimise perfusion and oxygen delivery to vital organs

A- Ensure patency
B- Oxygen should be given in all cases
C- Early use of IO needle for access, adequate fluid resuscitation at 10ml/kg of a crystalloid isotonic
-Correction of acid base disturbances, electrolyte imbalances, myocardial support- early use of inotropes such as adrenaline and noradrenaline. Maintain blood glucose levels and correct coagulopathies
-Early steroids if secondary infection (but only once the inotropes are running)
-Early administration of empiric broad spectrum antibiotics
-Collect blood cultures
-Measure lactate
-Treat underlying cause (sepsis with antibiotic cover)