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Plasma expanders

Plasma expanders. Dept. of Pharmacology CIPS. Shock. Circulatory failure: oxygen delivery (DO2) fails to meet the metabolic requirements of the tissues. 5L. CO=. Capacity=. 5L. 5L. Blood volume=. ?3L. CO=. Volume failure. Capacity=. 5L. 3L. Blood volume=. Hypovolemic shock.

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Plasma expanders

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  1. Plasma expanders Dept. of Pharmacology CIPS

  2. Shock Circulatory failure: oxygen delivery (DO2) fails to meet the metabolic requirements of the tissues

  3. 5L CO= Capacity= • 5L • 5L Blood volume=

  4. ?3L CO= Volume failure Capacity= 5L 3L Blood volume= Hypovolemic shock

  5. Hypovolemic shock ?3L CO= Volume failure Capacity=5L Volume=3L Pump failure Capacity=5L Volume=5L Cardiogenic shock

  6. Cardiogenic shock • 3L CO= Hypovolemic shock Volume failure Pump failure Capacity=5L Capacity=5L Volume=5L Volume=3L Distribution failure Capacity= • 8L Blood volume= • 5L Distributive shock

  7. Hypovolemic shock Cardiogenic shock Volume failure Pump failure Capacity=5L Capacity=5L CO= • 3L Volume=5L Volume=3L Distributive shock Capacity=5L Distribution failure Volume=5L Capacity=8L Blood Volume=5L Obstructive shock

  8. Hypovolemic shock Stages of shock Volume failure Cardiogenic shock Non-progressive stage Pump failure Progressive stage Distribution failure Distributive shock Refractory [irreversible] stage Obstructive shock

  9. Plasma expanders Plasma expanders are high mol. Wt. substances which when infused IV exert osmotic pressure and remain in the body for a long time to increase the volume of circulating fluid a. Colloids • Dextran • Polyvinylpyrrolidine • Gelatin polymers • Hydroxyethyl starch b. Crystalloids • Normal saline • Dextrose • Dextrose Saline

  10. Requirements of an ideal plasma expander: 1. Oncotic pressure comparable to plasma. • Remain in the circulation for an adequate period and • Disposed of either by metabolic degradation or by excretion. • Not antigenic or pyrogenic. • Not interfere with grouping and cross matching of blood. • Use of plasma expanders: • Hypovolemic shock. • Burns. • Severe trauma. • Endotoxin shock. Contraindications: • Severe anaemia. • Cardiac failure. • Pulmonary oedema. • Renal insufficiency.

  11. Colloidal plasma expanders • Substances of high Mol.Wt. • Remain long time in blood stream • Augment the volume of circulating fluid • By increasing the osmotic pressure Dextran: • It is a Polysaccharide[ made of many glucose molecules]. • Dextran 70 (MW – 70,000) & Dextran 40 ( MW – 40,000). • Oncotic pressure similar to plasma proteins and expands plasma volume for about 24 hours. • Large doses do not induce antibody formation. • They may interfere with coagulation and platelet function and also blood grouping. • Dextran – 70: Excreted very slowly by glomerular filtration and some amount deposited in RE cells.

  12. Dextran – 40: Reduces blood viscosity. • Excreted through renal tubules and occasionally may produce acute renal failure. Precautions should be taken. Caution: • Dextran does not provide necessary electrolytes and can cause hyponatremia or other electrolyte disturbances Dextran- other uses: • Antithrombotic in microsurgeries •  In some eye drops as a lubricant •  To solubilize other factors, e.g. iron (=iron dextran) • Used in laboratory tests Contraindications: • Allergy. • Heart failure. • Acute oliguric renal failure. • Hypofibrinogenemia. • Thrombocytopenia

  13. Hydroxyethyl starch[HES]: Compared to dextrans – • Maintains blood volume longer. • Does not cause acute renal failure or coagulation disturbances. Adverse effects: • Anaphylactoid reactions • Mild fever, Chilling, periorbital edema, urticaria, itching and chills. Polyvinylpyrrolidone[PVP]: • Synthetic polymer,MW- 40,000. • Interferes with blood grouping and cross matching. • Releases histamine. • Binds to penicillin and insulin.

  14. Gelatin polymer[Haemaccel]: • Does not interfere with grouping and cross matching. • Expands plasma volume for about 12 hours. • Not antigenic • Hypersensitivity and hypotension can occur. Crystalloids Normal saline: Very limited duration of action. Dextrose: • Osmolality is lower than serum. • Useful when kidney function is impaired. • Human albumin: • Obtained from pooled human plasma. • Crystalloid solutions must be infused concurrently for better action. • Does not interfere with coagulation. • Used as a vehicle for transfusing packed red cells.

  15. Pharmacotherapy of shock • Drug therapy aims at: • Managing specific causes: Volume, cardiac function, relieving obstruction etc. • Managing associated hemodynamic alterations • Dopamine or dobutamine, glucocorticoids, volume replacements &expanders • Undertaking life saving & life sustainable measures

  16. Thank You

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