Fluid Replacement Therapy

Question 1

Does a cell shrink/ swell in a hypotonic solution

Answer 1

Swells (hypotonic= low solute high water, so water osmoses into cell)

Question 2

Describe the flow of glucose and water upon giving 5% Dextrose

Also describe the effect on Osmolarity

Answer 2

• Glucose starts in Plasma then distributes across compartments, to be taken up by cells
• Water follows glucose across all compartments, reducing Osmolarity

(Intravascular-> Intersitial-> Intracellular)

Question 3

Why is 5% dextrose not a good choice to give to someone with mass fluid loss? (Haemorrhage)

When would you give?

Answer 3

• Of a litre of fluid, only 84ml stays in Plasma

- To maintain hydration

Question 4

Describe the flow of 0.9% Saline across compartments and its effect on osmolarity

Answer 4

• Na remains in ECF

- No change in Osmolarity

Question 5

Describe the flow of Hartman’s across compartments and its effect on osmolarity

Answer 5

• Majorly remained in ECF

- Osmolarity retained

Question 6

Describe the flow across compartments of 1000ml 4% Dextrose + 0.18% Saline

This is effectively 200ml 0.9% saline and 800ml 5% Dextrose

Answer 6

• Due to Dextrose,800ml of water moves across all compartments, reducing Osmolarity
• 200ml of Saline remains in ECF

Question 7

List 5 times a patient would need fluids

Answer 7

• No/ unsafe intake by mouth
• Malfunctioning GI Tract
• Dehydration
• Fluid losses
• Abnormal electrolytes

Question 8

KCl can be added to 1L fluid bags other than Hartmann’s.

What are 2 possible concentrations that can be used?

Answer 8

40mM and 20 mM

In these bags, K and Cl concentrations are equal e.g 40 K and 40Cl