Fluid Management

Question 1

Reasons for fluid prescription

Answer 1

Resus

Maintenance

Replacement

Question 2

General key considerations to take into account

Answer 2

Aim of fluid? Resus, maintenance, or replacement?

Weight and size of the patient?

Are there any co-morbidities?

Underlying reason for admission?

Most recent electrolytes?

Question 3

Fluid input

Answer 3

3/5ths from fluids via enteric route

2/5ths from both food and metabolic processes

Question 4

Fluid output

Answer 4

Urine 1.5 L

Respiration 0.4 L

Sweating 0.5 L

Faeces 0.1 L

Question 5

What are insensible losses?

Answer 5

Fluid loss from non-urine sources

Question 6

When will insensible losses rise?

Answer 6

In unwell patients like febriles, tachypnoeic or having increased bowel output.

Question 7

Signs of dehydration

Answer 7

Dry mucous membranes and reduced skin turgor

Decreasing urine output

Orthostatic hypotension

Increased capillary refill time

Tachycardia

Low BP

Question 8

Fluid overloaded signs

Answer 8

Raised JVP

Peripheral or sacral oedema

Pulmonary oedema

Question 9

What to monitor in fluid status?

Answer 9

Fluid input-output chart and daily weight chart

U&Es, evidence of dehydration, renal hypoperfusion, or electrolyte abnormalities

Question 10

Daily requirement of water, Na+, K+ and glucose

Answer 10

Water = 25 ml/KG/day

Na+ = 1.o mmol/kg/day

K+ = 1.0 mmol/kg/day

Glucose 50g/day

Question 11

Maintenance requirements for a 70kg healthy male

Answer 11

1750ml of water

70mmol of Na+

70mmol of K+

50g of glucose

Question 12

What should be a typical fluid maintenenace regimen for a 70kg healthy male.

Answer 12

First bag = 500ml of 0.9% saline with 20mmol/L K+ for 8 hours. (all of saline is covered here an approx 1/3 K+ and 1/4th water.

Second bag = 1L of 5% dextrose iwth 20mmol/L K+ for 8 hours.

Third bag = 500 ml of 5% dextrose with 20mmol/L K+ to run over 8 hours.

Question 13

How should a reduced urine output <0.5ml/kg/hr be managed?

Answer 13

Aggressively giving a fluid challenge and the lcinical parameters with urine output.

Question 14

Explain fluid challenge in reduced urine output.

Answer 14

250ml or 500ml over 15-30 minutes depending on size and co-mobidities.

120 kg 30 yr male would need >500ml, frail old lady 250ml

Question 15

Assessment before replacing ongoing losses.

Answer 15

Are there any third-space losses?

Is there diuresis?

Tachypnoeic or febrile?

Passing more stool than usual?

Losing electrolyte-rich fluid