Fluid management

Question 1

What are the different reasons for fluid prescription?

Answer 1

• Maintenance
• Replacement
• Resuscitation

Question 2

What are the key considerations to remember when prescribing fluids?

Answer 2

• Maintenance? Resuscitation? Replacement?
• Weight and size of the patient?
• Co-morbidities: heart failure? kidney disease?
• Reason for admission?
• Underlying electrolytes?

Question 3

Describe the general distribution of water in the body?

Answer 3

• 2/3 intracellular fluid
• 1/3 extracellular fluid
  
  • 1/5 in intravascular space
  • 4/5 in interstitium

Question 4

Where do you want fluid to go when you are giving general maintenance fluids?

Answer 4

Aim is to distribute fluid into all compartments

Question 5

Where do you want fluid to go when you are giving general resuscitation fluids?

Answer 5

Aim for fluids to stay within intracellular space

Question 6

What does fluid resuscitation generally mean?

Answer 6

Improving tissue perfusion by raising the intravascular volume

Question 7

Why are fluids important in septic patients?

Answer 7

• Tight junctions between the capillary endothelial cells break down and vascular permeability increases
  
  • Increasing hydrostatic pressures and reducing oncotic pressure
  • => fluid leaves vasculature and enters the tissue
• Give large volumes of fluid even though total body water is high
• Monitor fluid balance closely

Question 8

Fluid input and output proportions

Answer 8

Question 9

What are the signs that a patient is fluid depleted?

Answer 9

• Dry mucous membranes and reduced skin turgor
• Decreasing urine output (>0.5ml/kg/hr)
• Orthostatic hypotension
• In severe cases:
  
  • Decreased capillary refill time
  • Tachycardia
  • Low blood pressure

Question 10

What are the signs that a patient is fluid overloaded?

Answer 10

• Raised JVP
• Peripheral or sacral oedema
• Pulmonary oedema

Question 11

What are the daily requirements of water, sodium, potassium and glucose?

Answer 11

• Water: 25 mL/kg/day
• Na+: 1 mmol/kg/day
• K+: 1 mmol/kg/day
• Glucose: 50g/day

Question 12

What are the two broad categories of intravenous fluids?

Answer 12

• Crystalloids
• Colloids

Question 13

Describe crystalloids?

Answer 13

• Aqueous solutions of minteral salts or other water-soluble molecules
• Common in acute setting, theatre and for maintenance

Question 14

Describe colloids?

Answer 14

• Contain large insolble molecules such as gelatin
• Blood is a colloid
• Colloids have a high colloid osmotic pressure therefore increase intravascular volume faster than crystalloids
  
  • Evidence suggests this offers no actual clinical benefit

Question 15

Composition of the commonly used fludi types

Answer 15