PLASMA EXPANDERS

B i.e. Plasma expander

Ans. is ‘a’ i.e., Blood group matching; ‘b’ i.e., Causes thrombocytopenia

o Dextran is a polysaccharide obtained form sugar beet. It is plasma expander and have all properties of an ideal plasma expander except :

a)    May interfere with blood grouping and cross matching.

b)    Some polysaccharide reacting antibodies if present in pts may cross-react with dextran and trigger an anaphylactoid reaction. (Though the dextran is not antigenic).

c)   They coat the platelets and coagulation factors and may interfere with coagulation and platelet function, thus prolong bleeding times. Not used when hypofibrinogenemia, thrombocytopenia or bleeding pts.

Dextran prevent roleaux formation of RBC’s and have anti-sludging effects, thereby increases microcirculation.

Ans. is ‘b’ i.e., Dextran 40

o Dextran 40 and 70 interferes with coagulation and platelet function and thus prolong bleeding time and so is not used in hypofibrinogenemia, thrombocytopenia or in presence of bleeding.

o Dextran 40 has been tried in stroke, in DVT prophylaxis and pulmonary infarction.

Ans. is ‘c’ i.e., Dextran 40 

Ans. c. Polygeline

Polygeline is a plasma expander similar to the albumin, has a molecular weight of 30,000 and causes less hypersensitivity reactions but should be used with caution

Polygeline

• Polypeptide with average MW 30,000^Q
• Exerts oncotic pressure similar to albumin^Q
• Not antigenic, hypersensitivity reactions are rare^Q but should be watched for.
• Does not interfere with grouping and cross matching of blood^Q
• Remains stable for three years.
• It is not metabolized in the body; excreted slowly by the kidney.
• Expansion of plasma volume lasts for 12 hours.
• It is more expensive than dextran
• It can also be used for priming of heart-lung and dialysis machines

Hydro xyethyl

• It is a complex mixture of ethoxylated amylopectin of various molecular sizes

Starch

• Average MW 4.5 lac

(HES)

• The colloidal properties of 6% HES approximate those of human albumin.
• Adverse effects: Vomiting, mild fever, itching, chills, flu like symptoms, swelling of salivary glands,
• urticaria, periorbital edema and bronchospasm are the anaphylactoid reactions

Polyvinypyr-rolidone

• It is a synthetic polymer used as a 3.5% solution.
• It interferes with blood grouping and cross-matching
• Releases histamine

Dextran

• It is a polysaccharide obtained from catgut beat, which is available in two forms.
• Dextran-70 (MW 70,000)
• Dextran-40 (MW 40,000)
• Though the dextran used clinically is not antigenic, its structure is similar to other antigenic polysaccharides
• Some polysaccharide reacting antibodies, if present, may cross react with dextran and trigger anaphylactic reaction.

Ans. is ‘c’ i.e., Plasma expander 

Plasma expanders

• These are high molecular weight substances which exerts colloidal osmotic (oncotic) pressure, and when infused i.v. retain fluid in the vascular compartment.
• Human plasma or reconstituted huma albumin are the best, However, the former carries the risk of transmitting serum hepatitis, AIDS, and latter is expensive. Therefore synthetic colloids are more often used. 
• Desirable properties of plasma expander are :

1. Should exert oncotic pressure comparable to plasma.
2. Should remain in circulation and not leak out in tissues, or be too rapidly disposed.
3. Should be pharmacodynamically inert.