Colloids (ASAN002/8)

Question 1

What are Colloids? (1)

Answer 1

Solutions that contain large molecules that do not readily pass through membranes.

Question 2

What are the main characteristic of Colloids? (2)

Answer 2

Have an osmolarity > extracellular space.
(fluid is drawn into blood vessels)

Question 3

What is the main difference between Colloids & Crystalloids? (1)

Answer 3

Colloids contain large molecules designed to stay in intravenous space longer than crystalloids.

Question 4

Why are Colloids sometimes referred to as ‘Plasma Expanders’? (2)

Answer 4

Due to their ability to draw fluid out of interstitial & intracellular spaces into plasma.
Therefore maintain vascular volume more effectively.

Question 5

What are the main indications for using Colloids? (2)

Answer 5

• Hypovolaemic shock
• Hypoproteinaemia

Question 6

How are Colloids usually Administered? (2)

Answer 6

• Often given as a bolus (supported with crystalloid fluids)
• or over several hours.

Question 7

IMAGE – Colloid molecules do not pass through membrane.

Answer 7

Question 8

What are some examples of Synthetic Colloids? (4)

Answer 8

• Voluven 6%
• Hetastarch
• Haemacell
• Gelofusin

Question 9

What are the constituents of Voluven 6%?

Answer 9

6% hydroxyethyl starch in 0.9% NaCl.

Question 10

What is Voluven 6% mainly used for? (1)

Answer 10

Plasma volume replacement.

Question 11

Why is Voluven 6% NOT a substitue for Fresh Whole Blood (FWB)? (1)

Answer 11

DOES NOT replace RBC or clotting factors.

Question 12

What are the storage instructions for Voluven 6%? (2)

Answer 12

• Store below 25℃
• DO NOT FREEZE.

Question 13

What are the Contraindications of Voluven 6%? (2)

Answer 13

Do not use in patients with:
* Pre–exisiting disorders of haemostasis & coagulation.
* Established renal failure.

Question 14

What are the Side-effects of Voluven 6%? (3)

Answer 14

• Minor allergic reactions due to histamine release.
• Transient ↑ in bleeding time may occur.
• Hypersensitivity reactions may occur – incl. (but rare) severe anaphylactic reactions.

Question 15

What is the dose rate of Voluven 6%? (2)

Answer 15

Up to 50ml/kg/day
(coagulation problems occur if larger amts given)

Question 16

How should Voluven 6% be administered? (3)

Answer 16

• Continuous infusion (calculated at 1 – 2 mls/kg/hr)
• Larger bolus over shorter period (calculated at 20 – 40mls/kg/day) = larger amt given over 2hrs instead of smaller amt over 8hrs.
• MUST NOT EXCEED 50ml/kg/day.

Question 17

What is the rate for continuous infustion of Voluven 6%? (1)

Answer 17

1 - 2 mls/kg/hr

Question 18

What is the rate for Voluven 6% bolus given over 2hrs? (3)

Answer 18

• 20 – 40mls/kg/day
• Larger amt given over 2hrs instead of smaller amt over 8hrs.
• MUST NOT EXCEED 50mls/kg/day!

Question 19

Hetastarch

Answer 19

Hydroxyethyl starch.\nUsed as plasma volume expander.\nHigh molecular weight.\nOncontic effects last 24hrs – can remain in the body for weeks.

Question 20

Hetastarch – Contraindications:

Answer 20

Do not use in patients with:\nPre–existing disorders of haemostasis & coagulation.\nEstablished renal failure.

Question 21

Hetastarch – Side–effects:

Answer 21

Minor allergic reactions due to histamine release.\nTransient ↑ in bleeding time may occur. \nHypersensitivity reactions may occur – incl. (but rare) severe anaphylactic reactions.

Question 22

Haemacell & Gelofusin

Answer 22

Isotonic gelatine based fluids.\nUsed as plasma expanders.\nPromote fluid retention within vascular system.\nLow molecular weight for a colloid.\nExcreted rapidly – only remains in vascular space for 2 – 4 hrs.

Question 23

Haemacell & Gelofusin – Contraindications:

Answer 23

Do not use in patients with:\nEstablished renal failure.

Question 24

Haemacell & Gelofusin – Side–effects:

Answer 24

Minor allergic reactions due to histamine release.\nTransient ↑ in bleeding time may occur. \nHypersensitivity reactions may occur – incl. (but rare) severe anaphylactic reactions.