Fluids and Transfusions

Question 1

How much water does a person need in a day?

Answer 1

25-30ml/kg

Question 2

How much sodium does a person need in a day?

Answer 2

1-2 mmol/kg

Question 3

How much potassium does a person need in a day?

Answer 3

0.5-1 mmol/kg

Question 4

How much chloride does a person need in a day?

Answer 4

1 mmol/kg

Question 5

How much glucose does a person need in a day?

Answer 5

50-100g

Question 6

What is the difference between crystalloids and colloids?

Answer 6

• Crystalloids - Ionic

- Colloids - Large molecules e.g. albumin

Question 7

Why aren’t colloids used so much now? (2)

Answer 7

• Anaphylaxis

- No evidence that they’re any better than crystalloids at resuscitation

Question 8

How much Na, K, Cl and Bicarb in 0.9 Sodium Chloride? (1 litre)

Answer 8

Na 154 mmol
K (can have 20 or 40 added)
Cl 154 mmol
Bicarb 0

Question 9

How much Na, K, Cl and Bicarb in 0.5 Dextrose? (1 Litre)

Answer 9

Na 0
K 0 (can have potassium added)
Cl 0
Bicarb 0

Question 10

How much glucose is in 0.5 dextrose?

Answer 10

50g

Question 11

How much Na, K, Cl and Bicarb in 0.9 Hartmann’s? (1 litre)

Answer 11

Na 131
K 5
Cl 111
Bicarb 29

Question 12

How is resuscitation achieved?

Answer 12

500ml normal saline over 15 minutes

Question 13

What should you look for as a cause of fluid loss?

Answer 13

• Third space losses e.g. obstruction or pancreatitis
• Diuresis
• Tachyp, febrile
• High stoma output
• Electrolyte rich fluid losses

Question 14

What imbalance does vomiting cause?

Answer 14

Alkalosis

• low H+
• low K
• low Cl

Question 15

What imbalance does diarrhoea cause?

Answer 15

Acidosis

- low K

Question 16

Why does vomiting cause alkalosis?

Answer 16

Hydrogen ion loss (stomach acid) so pH rises

Question 17

When should a patient be transfused?

Answer 17

Hb less than 80

Question 18

Describe the water distribution in a 70kg male.

Answer 18

42kg is water

2/3 intracellular (28)

Of remaining 14 (extra-c), 3 litres is intravascular

3 litres water + 2 litres RBCs makes 5 litres of blood

Question 19

What is the normal plasma osmalality?

Answer 19

285-295 mOsmol/kg

Question 20

What happens to the sugar in dextrose?

Answer 20

Rapid uptake into cells

Question 21

What happens when hypertonic solution is given?

Answer 21

RBCs shrivel as water moves out

Question 22

What happens as hypotonic fluid is given?

Answer 22

RBCs swell

Question 23

Where else can you look to assess a patient’s fluids?

Answer 23

• Mucosa
• BP
• Urine output
• Cap refill