Fluid Management

Question 1

What are the normal volumes in the following compartments:
- Intravascular,
- Interstitial,
- Intracellular

Answer 1

Intravascular - 5L
Interstitial - 10L,
Intracellular - 30L

Question 2

What are some of the problems with fluid/electrolyte balance?

Answer 2

• Imbalance between input/output. Either inadequate hydrations or excess losses (diarrhoea, vomiting or stomas)
• Redistribution into wrong compartments
• Osmolar problems, for example correcting sodium too quickly can cause cerebral oedema

Question 3

What are the aims of fluid management?

Answer 3

• Maintenance fluids
• Replacement fluids
• Resuscitation fluids

Question 4

What are the signs of hypovolaemia?

Answer 4

• Reduced skin turgor,
• Dry mucous membranes,
• Capillary refill greater than 2s,
• Postural hypotension,
• Decreased urine output,
• Tachycardia

Question 5

What are the signs of fluid overload?

Answer 5

• Raised JVP,
• Oedema,
• Lung crackles (pulmonary oedema)

Question 6

Explain a fluid challange

Answer 6

• Deliver roughly 500ml of fluid over 15mins. Can continued to do this up till 2000mls.
• In patients with comorbidities such as heart failure or renal impairment start with 250mls

Question 7

At what rate do you give maintenance fluids?

Answer 7

• 30mls/hour/24 hours.
• Never give more than 100mls per hour for maintenance

Question 8

What are the Nice ‘5 Rs’ regarding fluid prescribing?

Answer 8

• Resuscitation,
• Routine maintancence,
• Redistribution,
• Replacement,
• Reassessment

Question 9

When should you start maintenance fluids?

Answer 9

If patients are not drinking/unable to drink/fasting for over 8-12 hours then they should be started on IV maintenance fluids

Question 10

Name some examples of crystalloids

Answer 10

• Saline 0.9%
• Dextrose
• Hartmann’s

Question 11

What are coloids?

Answer 11

Fluids which have a high osmotic pressure so mainly stay in the intravascular space. Theoretically meant to raise intravascular volume faster than crystalloids but no evidence that they do.

Question 12

What are the normal daily requirements of fluid and electrolytes?

Answer 12

water - 25ml/kg/day
Na - 1mmol/kg/day
K+ - 1mmol/kg/day
Glucose - 50g/day

Question 13

What are the main electrolyte disturbances with vomiting and diarrhoea

Answer 13

Vomiting - Low potassium, low chloride and alkalosis.
Diarrhoea - Low potassium and acidosis