Fluid Replacement Therapy

Question 1

What % of the total body weight is fluid in a newborn baby?

Answer 1

75%

Question 2

What % of the total body weight is fluid in the eldery?

Answer 2

45%
Decreasing muscle mass

Question 3

What % of the total body weight is fluid in a man?

Answer 3

60%

Question 4

What % of the total body weight is fluid in a female?

Answer 4

55%

Question 5

Why does fluid take up more of the total body weight in men than women?

Answer 5

Men have more muscle mass
Water is stored in the muscle

Question 6

Why do patients need fluids?

Answer 6

Nil by mouth
Malfunction in GI tract
Dehydration
Fluid loss
Abnormal electrolyte levels

Question 7

What are the 5Rs of fluid prescription

Answer 7

Resuscitation
Routine Maintenance
Replacement + Redistribution
Reassessment

Question 8

How can you add K+ to fluids?

Answer 8

As KCl
As 20 or 40mmol

Question 9

What fluid bag can you not modify?

Answer 9

Hartmann’s

Question 10

What happens if you administer 5% dextrose in 1L bag?

Answer 10

• glucose taken up by cells rapidly
• H2O is left and distributed through all compartments

Question 11

What happens if you administer 0.9% saline?

Answer 11

• osmolarity is similar to ICF so liquid says in ECF
• distributes proportionally between interstitium 75% and plasma 25%
• contains Na+ and Cl-

Question 12

What happens when you administer Hartmann’s?

Answer 12

• osmolarity is similar to ICF so liquid says in ECF
• distributes proportionally between interstitium 75% and plasma 25%
• contains Na+, Cl-, K+, Ca+ and lactate (HCO3-)

Question 13

What fluids are the first choice for resuscitation?

Answer 13

Hartmann’s
Saline

Question 14

What happens when you administer 4% dextrose/0.18% saline in a 1000ml bag?
(200ml 0.9% saline + 800ml 5% dextrose)

Answer 14

• 800ml H2O reduces osmolarity across ALL compartments from 5% dextrose (+glucose taken up by cells)
• 200ml 0.9% saline remains in ECF + distributes proportionally across interstitium 75% + intravascular space 25%

Question 15

When are maintenance fluids needed?

Answer 15

Patient is haemodynamically stable but unable to meet their daily fluid requirements via oral or enteral routes
e.g. Nil by mouth before surgery

Question 16

When are resuscitation fluids needed?

Answer 16

Patients in hypovolaemic state

Question 17

When are replacement fluids needed?
How do you decide what is needed?

Answer 17

• required to replace the loss of bodily fluids
• choice of fluid depends on what’s being lost
• context dependent: volume needed, is it ongoing?

Question 18

What time should you administer maintenance fluids?
Why?

Answer 18

During the daytime
To prevent sleep disturbance

Question 19

What are indicators that a patient may need urgent fluid resuscitation?

Answer 19

• Systolic BP <100mmHg
• > 90bpm
• Cap refil time >2 seconds
• Cold peripheries
• > 20 resp rate
• NEWS >5
• Passive leg raising suggests fluid responsiveness

Question 20

How much water do you need a day?

Answer 20

25-30ml/kg/day

Question 21

How much glucose is needed per day?

Answer 21

50-100g
Regardless of weight

Question 22

How much K+ Na+ Cl+ is needed per day?

Answer 22

1mmol/kg/day

Question 23

What is the composition of fluid in the body?

Answer 23

2/3 intracellular fluid ICF
1/3 extracellular fluid ICF > 75% interstitial fuid 25% plasma

Question 24

What is the composition of extracellular fluid?

Answer 24

75% interstitial fluid
25% plasma

Question 25

Examples of crystalloid fluids

Answer 25

Saline
Dextrose
Hartmann’s

Question 26

Why is saline used for bolus fluids but not maintenance?
What risk does it have?

Answer 26

Risk of hypercholermic metabolic acidosis

Question 27

What are the types of fluids you can give?
Composition
Examples

Answer 27

• crystalloids: small molecules that can diffuse through capillary wall e.g. saline, hartmann’s dextrose
• colloid: large molecules that do not diffuse out of capillaries e.g.blood

Question 28

When would you give 3% hypertonic saline?

Answer 28

In patients with raised intracranial pressure

Question 29

When would you give 7% hypertonic saline?

Answer 29

Nebulised to help with respiratory secretions

Question 30

What acid base status can be improved by giving fluids?

Answer 30

Metabolic acidosis

Question 31

Outline resuscitation fluids

Answer 31

• Saline 0.9% or Hartmann’s 500ml over 15 mins
• if risk of fluid overload: 250ml over 15 mins
• seek senior helps if needing >2L
  .
• if due to haemorrhage, replace with blood

Question 32

What needs to be replaced in diarrhoea patients?

Answer 32

HCO3-

Question 33

Outline resuscitation fluids in paediatrics

Answer 33

• Hartman’s or 0.9% saline 10ml/kg in 15 mins
• normally intraosseous
• seek senior helps at 40-60ml/kg

Question 34

Outline maintenance fluids in paediatrics

Answer 34

• Holliday Segar method - 4,2,1 method
• first 10kg: 4ml/kg
• second 10kg: 2ml/kg
• every kg after: 1ml/kg
• 0.45% saline 20mmol/L KCl + 5% dextrose

Question 35

Prescribe maintenance fluids in a 36kg child

Answer 35

• 4,2,1
• first 10kg: 4x10 = 40ml/kg
• second 10kg: 2x10 = 20ml/kg
• every kg after: 1x16 = 16ml/kg
• total: 40+20+16 = 76ml/hr
• of 0.45% saline 20mmol/L KCl + 5% dextrose

Question 36

Outline replacement fluids in paediatrics

Answer 36

• %dehydration x weight (kg) x 10 = fluid deficit (ml) over 12-24 hours
• moderate dehydration: 5%
• severe: 10%
• critical: 15%

Question 37

Calculate the replacement fluids in a 7 year old 22kg child with moderate dehydration

Answer 37

%dehydration x weight (kg) x 10 = fluid deficit (ml) over 12-24 hours
- 5% x 22 x 10 = 1100ml over 12-24 hours of 0.45% saline 20mmol/L KCl + 5% dextrose

Question 38

What fluids do you give for maintenance + replacement in paediatrics?

Answer 38

0.45% saline 20mmol/L KCl + 5% dextrose