Fluid Balances

Question 1

Why is metformin stopped on sick days?

Answer 1

When patient is dehydrated they can get lactic acidosis

Question 2

What types of medications are stopped on sick days?

Answer 2

• ACEi
• ARBs
• NSAIDs
• Diuretics
• Metformin

Question 3

How much more intracellular fluid is there than extracellular?

Answer 3

2x

Question 4

How many litres of water are there in the body?

Answer 4

43L

Question 5

What solutions are given to for hypotensive patients?

Answer 5

Isotonic fluids (e.g 0.9%NaCl, lactated ringers)

Question 6

What type of solutions are given for normotensive patients?

Answer 6

Hypotonic solutions (e.g 0.45% NaCl)

Question 7

Where do hypotonic fluids draw fluid to?

Answer 7

Into cells (away from plasma)
- May cause oedema

Question 8

Is 5% dextrose hypotonic or isotonic?

Answer 8

Hypotonic (generally speaking)

Question 9

What can 5% dextrose cause if given too quickly?

Answer 9

Hyponatremia

Question 10

What is 5% dextrose not good for?

Answer 10

Replacing plasma/blood loss

Question 11

What is more physiological 0.9% NaCl, 5% dextrose or Hartmann’s?

Answer 11

• Hartmann’s is the most physiological (close to plasma)
• 0.9% NaCl is next
• Dextrose is least physiological (close to plasma)

Question 12

What are some possible side-effects of 0.9% NaCl?

Answer 12

• May cause hypernatremia
• May cause renotoxicity
  as massive Na+ load on kidneys may cause vasocontriction
• May cause hypercholemic acidosis

Question 13

When is Hartmann’s fluid best used?

Answer 13

• Replacing plasma during surgery or GI losses

- Should not be used in maintenance alone

Question 14

What are possible side-effects of Hartmann’s fluid?

Answer 14

Hypernatremia and hypokalemia (K+ and magnesium cannot be added to the bag)

Question 15

When are lactated ringers recommended?

Answer 15

• Burns
• Acute blood loss
• Metabolic acidosis

Question 16

How are lactated ringers given?

Answer 16

As a bolus

Question 17

When are lactated ringers not recommended?

Answer 17

pH > 7.5

Question 18

When are hypotonic solutions such as 0.45% NaCl used?

Answer 18

• Hypernatremia or DKA

- Draws more fluid into cells and out of plasma

Question 19

What can colloids such as albumins and starch cause?

Answer 19

Ananphalaxis and renal failure

Question 20

What are the 2 main types of isotonic crystalloids?

Answer 20

• 0.9% saline

- Balanced crystalloid (Hartmann’s, lactated ringers)

Question 21

When is 0.45% NaCl contraindicated?

Answer 21

• Burns
• Trauma
• Liver disease
  As the fluid draws fluid out of plasma