Fluids
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This document discusses different types of intravenous fluids used in anesthesia. Fluids are divided into crystalloids and colloids. Common crystalloids include Ringer's lactate, normal saline, and glucose solutions. Common colloids discussed include dextrans, albumin, gelatins, hydroxyethyl starch, and blood. Each type of fluid is described in terms of its composition, uses, advantages, and disadvantages. Guidelines for blood transfusion and issues with mixing different IV fluids are also summarized.
Fluids
- 1. L E C T U R E R : U M A R T A R I Q M S C O T T / A N A E S T H E S I A FLUIDS
- 2. FLUIDS Fluids are divided into crystalloids and colloids CRYSTALLOIDS Ringer lactate Normal saline Glucose solutions Dextrose normal saline Hypertonic saline
- 3. COLLOIDS Dextrans Albumin Gelatins Hydroxyethyl starch Blood
- 4. CRYSTALLOIDS 1. Ringer lactate solution(Hartman solution) It is the lactated ringers solution, which is modified NS in which some of the sodium molecules are replaced by potassium and calcium. RL is given to correct electrolyte loss and fluid loss in the patients e,g diarrhoea , vomiting. Lactate is metabolised to bicarbonate in liver.
- 5. Ringer lactate is slightly hypotonic. Blood should not be given through the same drip set(because RL contains calcium) Ringer lactate is a crystalloid of choice for blood loss replacement.
- 6. Composition of ringer lactate is Na 131 mEq/l Cl 111 mEq/l K 5 mEq/l Ca 2 mEq/l Lactate 29 mEq/l pH=6.5
- 7. 2. NORMAL SALINE It is a solution of 0.9% NaCl which is isotonic. NS is given to compensate dehydration and sodium loss in cholera and excessive sweating patients . It is also used as day care fluid in patients admitted in hospitals. It is preferred over ringer lactate for treating ; 1. Hypochloremic metabolic alkalosis. 2. Brain injury(Ca in lactate can increase the neuronal injury) 3. Hyponatermia Ph= 5.5 commonly used crystalloid
- 8. Composition of Normal saline Na 154 mEq/l Cl 154 mEq/l
- 9. GLUCOSE SOLUTIONS(5% ,10% dextrose) These are isotonic but with the metabolism glucose inside body becomes hypotonic. Blood cannot be given through the same drip set otherwise rouleaux formation will cause clumping of RBC`S. It is used to treat low blood sugar or water loss without electrolyte loss.
- 10. DEXTROSE NORMAL SALINE (DNS) DNS is hypertonic 1/5 NS + 4.3% dextrose and 5% dextrose + ¼ NS are isotonic solutions. These are best used as maintenance of fluids. Used to supply water, calories and electrolytes(e,g sodium chloride) to the body
- 11. HYPERTONIC SALINE used for treating hyponatermia cerebral and pulmonary edema.
- 12. COLLOIDS 1. DEXTRANS(Lomodex) Available as dextran 70 (mol.wt. 70,000 Daltons),150 (mol.wt. 1,50,000) and 40 (mol.wt. 40,000 Daltons). Dextrans are polysaccharides These solutions can be stored for 10 years Half life of dextran is 2-8 hours
- 13. ADVANTAGES Dextrans are non toxic , neutral and chemically inert. Low molecular weight dextran (dextran 40 ) improves microcirculation. DRAWBACKS Dextrans interfere with blood grouping and cross matching(because they can cause red cell aggregation) Interferes with platelet function Can cause severe anaphylaxis Large molecular weight dextrans can block renal tubules ARDS (rarely) because of direct toxic effect on pulmonary capillaries.
- 14. ALBUMINS Available as 5% and 25% solution. These are very expensive Albumin has intravascular halflife of 10-15 days Used when there is protein loss from the body like in I. Peritonitis II. Liver failure III. Burns IV. Protein losing enteropathies
- 15. GELATINS(Haemaccel) Molecular weight is 30,000 Available as 3.55 solution. Expand plasma effectively for 2 hours(25% may be present in blood after 12 hours) Gelatins do not interfere with blood grouping, platelet function and clotting but at high doses they can also interfere with clotting . Incidence of severe anaphylactic reactions is very less. Haemaccel contains high calcium therefore citrated blood should not be mixed
- 16. Composition of haemaccel: Each liter contains: Gelatin 35 g Sodium 145 mEq Chloride 145 mEq Potassium 5 mEq Calcium 12 mEq
- 17. HYDROXYETHYL STARCH Two kinds of hydroxyethyl straches are available 1. Hexastarch 2. Pentastarch. Available as 6% & 10% solution. Prolonged half life Expand plasma effectively for 4 hours. Improves microcirculation & hence improves oxygen delivery to tissues. At clinically used dose they do not interfere with clotting but at high doses (>20ml/kg) they also interfere with clotting. Anaphylactic reactions are less common
- 18. Hextends Hextends is another hydoxylethyl starch which also has glucose and lactace but it is under trails and is considered to effect coagulation less than hydroxylethyl starch.
- 19. BLOOD In adults with normal HB and hematocrit blood loss more than 20 % of their blood volume should be replaced with blood while in western countries more than 25-30%. Losses less than 20% can be replaced with crystalloids and colloids( crystalloids preferred) In children's losses more than 10% is replaced with blood while in western countries losses more than 15% is replaced with blood.
- 20. Minimum acceptable HB level for elective surgery is 10 g% and hematocrit 35% 1 unit of blood raises 0.8 g% in india while in western countries by 1 g% because in india 1 unit of blood = 350 ml(301 ml of blood and 49 ml of anticoagulants) while in western countries 1 unit contains 450 ml of blood(out of which 63 ml is anticoagulant). One unit of fresh blood(with 100% RBCs while stored blood has only 70 & RBCs) increases HB by 1 g%
- 21. Blood products should not be mixed with 5 % dextrose (dextrose can cause hemolysis. RL and Haemaccel contains calcium which with citrate can induce clot formation.