8: Resuscitation in sepsis

Question 1

What is the definition of hypotension?

Answer 1

BP too low to perfuse tissues

< 90 / 60 mmHg or 40 below normal

Question 2

How does hypotension come about in sepsis?

Answer 2

Bacteria produce toxins

Toxins cause cytokine production

Cytokines cause VASODILATION and leaky capillaries > REDUCED BLOOD VOLUME

BP = CO x TPR

Question 3

What is a cytokine which causes hypotension in sepsis?

Answer 3

TNF alpha

Question 4

What does hypotension cause in sepsis?

Answer 4

Hypoperfusion of organs

=> ORGAN DAMAGE due to ISCHAEMIA and LACTIC ACIDOSIS

Question 5

How does lactic acidosis exacerbate sepsis?

Answer 5

Further vasodilation

Reduces cardiac output by reducing contractility of heart muscle

Cells can’t function outwith their optimum pH

Question 6

What is a renal problem caused by hypoperfusion in sepsis?

Answer 6

Acute kidney injury (AKI)

Question 7

What are clinical signs of hypovolaemia?

i.e dehydration

Answer 7

Cold peripheries, skin turgor, clammy

Tachycardia

Hypotension (including postural)

Decreased JVP

Dry mucuous membranes

Poor urine output

Question 8

Why does heart rate increase in sepsis?

Answer 8

Attempt to compensate for reduced BP

Question 9

Why does respiratory rate increase in sepsis?

Answer 9

Increased oxygen requirement of cells

Attempt to compensate for metabolic acidosis

Question 10

What is the normal level of lactate in the blood?

Answer 10

< 1.8 mmol/l

Question 11

What does an elevated lactate indicate?

Answer 11

Widespread anaerobic respiration

i.e widespread hypoperfusion –> hypoxia

Question 12

A lactate level of > ___ mmol/l is abnormal.

Answer 12

> 4 mmol/l

Question 13

How is urine output measured?

Answer 13

Directly (less accurate)

Catheter bag (more accurate)

Question 14

What is the minimum healthy urine output for a patient?

Answer 14

0.5 ml/kg/hr

which translates to about 30ml/hr in an adult

Question 15

In sepsis, ____ suggests renal hypoperfusion.

Answer 15

oliguria

< 0.5 ml/kg/hr

Question 16

What fluids are given to patients with sepsis?

Answer 16

0.9% NaCl, Hartmann’s solution

Crystalloids (gelofusin, blood transfusions) - don’t redistribute into soft tissue, “maintain oncotic pressure”

Question 17

What is a small risk of using colloid fluids e.g gelofusin?

Answer 17

Anaphylaxis

Question 18

What are some risks of blood transfusions?

Answer 18

Infection - e.g Hepatitis C

Transfusion reactions - Type II hypersensitivity, antibody-mediated reaction against RBCs

Question 19

What is a fluid challenge?

Answer 19

Initial resuscitation to replace water and salt

Repeat 500ml boluses of 0.9% NaCl or Hartmann’s, reassess vitals until resuscitated

Question 20

How much fluid is usually required to resuscitate someone?

Answer 20

2L

Question 21

It’s always better to give too ___ than too ___ fluid.

Answer 21

too much

too little

Question 22

What are the risks of

a) fluid overload
b) hypovolaemia?

Answer 22

a) Pulmonary oedema, treat with diuretics

b) Organ hypoperfusion, failure and death

Question 23

What changes in monitoring should be seen after fluid resuscitation?

Answer 23

Increased BP

Increased urine output

Reduced HR

Reduced lactate

Question 24

If a patient is still hypotensive after fluid resuscitation, what are they in?

What is the cause of the persistent hypotension?

Answer 24

Septic shock

Low TPR due to vasodilation

Rx: vasopressors (adrenaline, noradrenaline) which cause vasoconstriction and increased myocardial contractility

Question 25

What receptors do

a) adrenaline
b) noradrenaline act on?

Answer 25

Adrenaline is a mixed alpha/beta agonist

Noradrenaline acts on alpha receptors only

Question 26

What is the target MAP in septic shock?

Answer 26

> 65 mmHg

Question 27

How are inotropes given to someone in septic shock?

Answer 27

Central venous catheter

Question 28

What is the target urine output for someone in septic shock?

Answer 28

> 30 ml/hr

i.e > 0.5ml/kg/hr in a 60kg person