Fluid Therapy General Sergury 1 PDF

Select this paragraph to edit  Ob je ctiv Select th is paragraphes to edit To know about the distribution and metabolism of water and water balance  To know about sodium, potassium distribution normal values daily requirements  To...

Select this paragraph to edit  Ob je ctiv Select th is paragraphes to edit To know about the distribution and metabolism of water and water balance  To know about sodium, potassium distribution normal values daily requirements  To understand the abnormality of water metabolism and volume disturbances  To understand the basic of fluid therapy and types of fluids Select this paragraph to edit  Body water distribution  Water constitute 50-60% of body weight  Fluid compartments ICF 28L – 40 % of body weight ECF about 14L – 20 % of body weight Interstitial 10L –15 % Plasma 3L – 5 % Normal daily requirements and maintainance o 25-30m/kg / day of water o I mmol of Na. K+ and Cl- o Protein requirements 1gm/kg/day o Total calories in adults 18-65 , 2400-2000 k.c.  Control this balance : - Thirst mechanism : -  ADH secretion - reabsorption in collecting ducts  Aldosterone – Na reabsorption in DCT in exchange to K+ and H+  Renin_ angiotension cascade  Usually with conjunction of sodium Receptors o Osmotic receptors intracranial , hypothalamus o Volume receptors ( veins and right atrium) o Barro receptors and chemo receptors Carotid body aorta  For distribution between compartments  Hydrostatic pressure  Oncotic pressure “ plasma proteins  Sodium and potassium metabolism  Sodium is the extracellular cation  Potassium is the main intracellular cation Movements of Na+ and K+ between intra and extra cellular compartments is an active process,  Na+ - K+ ATP pump.  Sodium metabolism : - - Normal level of serum sodium is 135-145meq/L  Total body sodium is 4200 meq or mmol  Normal requirement is 1 – 1.5 meq/ kg/ day Mainly from food added salt ( 3-5 gm) and drink  Sodium excretion  Mainly through kidney up to 200 meq/ day , but quite variable  G.I.T  Skin  Potassium metabolism  Normal range 3.5 – 5 meq /L  Total body potassium is 50 meq/ Kg , 98% intracellular  Normal daily reqiurment is 1 meq / kg / day  Most potassium excreted in urine up to 700 meq /day  Osmolality and charged ion distribution  Normal blood osmolality is 280 – 300 mosmol / L Osmolality = 2x Na+ + ( glucose (mg) /18 + BUN / 2.8 Important to know in certain conditions, e.g. hypernatremia.  Body fluids are electrically neutral  The main charged ions are : -  Cations - K+ Na+, Ca , H+ ++  Anions – cl- , HCO3- - Extracellular po4-3 – main intracellular anion  Proteins , urea , glucose are uncharged but important to maintain balance of osmolality PERIOPERATIVE FLUID THERAPY To maintain normovolemia,Q&O2 delivery. To maintain electrolyte concentration. To maintain normoglycemia. Types of Fluids Crystalloids. Colloids. Crystalloids Aqueous solutions of low mol.wt. ions(salts) With or without glucose.  Sodium is the major osmotically active particle.  Crystalloid replacement shoud be 3 times the volume of lost  blood. Crystalloids Normal saline(NS). Lactated Ringer’s solution(LR). 5% dextose in water (D5W). Ringer’s acetate. D5LR. D5 NS. D5 ½ NS. Hypertonic saline(HS)3%. Normal Saline 0.9% NaCl (isotonic) 308 mOsm/L. Na 154 mEq/L. Cl 154 mEq/L. Uses: Hyponatremia. Brain injury. To dilute PRCs. Large quantity -- hyperchloremic metabolic acidosis. Normal Saline 1 gm Nacl 1000/58.5 = 17 mEq 1 L 0.9% Nacl 9 x 17=153 mEq 500 ml 75 mEq Lactated Ringer LR Osmolarity 273 mOsm/L Na 130 Cl 109 mEq/L K 4 Ca 3 mEq/L Lactate 28 mEq/L The most physiological solution. Lactate is converted into HCO3 in the liver Ca binds to citrate in PRC (not used as a diulent). Ringer Acetate Acetate 28 mEq/L Metabolism 2.5-4 times faster than lactate(in muscles). Dextrose 5% It functions as free water. 50 gm/L isotonic (253 mOsm/L). Uses: To maintain normoglycemia. To correct hypernatremia. To keep an IV line open for medication. Not used for volume expantion. During surgery only given for patients at increased risk of hypoglycemia(infants,insulin T). Avoided in critically ill (it increases CO2 production and aggravates ischemic brain injury). Select this paragraph to edit Select this paragraph to edit Hypertonic Saline HS 3% Osmolarity 1026 mOsm/L. mEq/L.Cl 513Na 513 It expands plasma volume by the increase in I.V pressure(fluids move from I.S to I.V osmotic crystalloids.fluid).More effective IN Uses: Severe hyponatremia. Early treatment of hypovol. shock.  Side effects: hypernatremia,hyperchloremia,hypokalemia and coag. Problems. Colloids Solutions containing high-molecular weight substances such as proteins or large glucose polymers. Plasma expanders by: volume of colloid. increasing plasma oncotic pressure moving fluids from IS to IV spaces. Colloids X Crystalloids Colloids stay more in IV space (3-6 h.). Crystalloids (20-30 m.). Colloids 3 times potent than crystalloids. Severe IV fluid deficits can be more rapidly corrected using colloids. Colloid resuscitation more expensive. Rapid administration of large amounts of crystalloids (>4-5L) is more frequently associated with significant tissue edema. Types of Colloids 1. Blood derived Human albumin. 2. Synthetic * Starches. * Gelatins. *Dextrans. Human Albumin 5% (isotonic) and 25% (hypertonic) in NS. Uses: Abnormal protein loss. e.g peritonitis. Severe burns. Expensive. No risk of viral infection. Rare allergic reactions. No effct on coagulation. Starches Hetastarch 6% Pentastarch 10% in NS. More effective than 5% albumin,gelatins and dextrans. Non antigenic;no effect on crossmatching. Lower cost than albumin. Cleared by the kidneys. Disadvantages: Coag.abnormalities if >1.5L. Rare anaphylactic reactions. Elevated serum amylase. Gelatins Haemagel Hemaccel. Relatively cheap. No effect on coagulation or on crossmatching. High incidence of allergic reactions. Dextrans Dextran 40 and 70 in NS or 5% dextrose. Anti-thrombotic effects. Dextran 70 is preferrd (12h.). Dextran 40 improves blood flow in microcirculat. Uses: *plasma expander. *To prevent thromboembolism (postop.). * To improve Blood Flow to ischemic limb (dextran 40). Dextrans Disadvantages: 1 Bleeding tendency. 2 Interfere with blood grouping and crossmatching. 3 Rare anaphylactic reactions. 4 Dextran 40 can precipitate in renal tubules leading to RF. Perioperative Fluid Therapy Compensatory IV volume expansion. Normal maintenance requirements. Pre-existing deficits. Surgical fluid losses: Blood. Other fluids. Compensatory IV volume expantion 5-7 ml/kg of crystalloid before anaesthesia. This to compensate for vasodilatation and cardiac depression by anaesth. drugs. Normal maintenance requirements For the first 10 kg: 4 ml/kg/h. For the next 10-20 kg: 2 ml/kg/h. Example: For each kg above 20 kg: add 1 ml/kg/h. Maintenance fluid needs for a 25 kg child: 40+20+5=65ml/hour.  Postoperative Water: as maintenance. Sodium: 1-1.5 mmol/kg/day. Potassium: 1 mmol/kg/day. 70 kg adult 2640 ml water 70-100 mmol Na 70 mmol K 2L dextrose 5% 100gm glucose 500 ml NS 75 mmol sodium Preexisting Deficits The deficit can be estimated by multiplying the normal maintenance rate by the length of the fast. 70 kg person fasting 8 h: 40+20+50 ml/h x 8h =880 ml. Consider abnormal losses. Surgical Fluid Losses Blood loss Continuous monitoring and accurate estimation of blood loss is v. important. for each 1 ml loss replace 3 ml crystalloids or 1 ml colloids. Other losses Evaporation from large exposed wounds or Third space losses. Select this paragraph to edit LR is the most physiological solution for routine use. Also AR. First litre D5LR (to prevent ketosis). Guidelines for fluid therapy 1 Short large-bore I.V. cannula. 2 The consequences of hypovolemia carry high mortality and must be treated promp. 3 Do not give inotropes to hypovol. pt. 4 For old,cardiac,hepatic or renal pt,replace gradually.Only half calc. deficit is given initially.CVP is mandatory. Guidelines for fluid therapy 5- Crystalloids,when given in sufficient amounts are just as effective as colloids. 3-4 times. 6 Severe deficits correct by colloids. 7 Rapid large amounts of crystalloids(>5L) is more freq. associated with tissue edema 8 Simple monitoring: ABP,HR & CVP ( 5-12 cmH2O). Plasma electrolytes (Na,K). Urinary output(>0.5 ml/kg/h). ABG. Blood Transfusion Homologous. Autologous. Indications Replacement of blood loss in shock. Treatment of anaemia. O2 carrying capac. Correction of coagulopathies. Blood products Whole blood. Some units separated for specific needs (blood banks). Blood bags contain CPDA citrate anticoagulant phosphate buffer dextrose red cell energy source adenosine precursor for ATP synth. Blood products Whole blood. Packed red cells PRCs. Platelet concentrate. Fresh frozen plasma FFP. Cryoprecipitate. Whole blood Uncommon product. One unit 450 ml of donor+63 ml anticoag. Stored at 4 c viable 21 days. Packed red cells PRCs Used widely. One unit 250-300 ml with Hct 50-80%. Stored at 1-6 c up to 35 days. One unit raises Hb 1gm/dl & 3% Hct. Used for improving O2 carr. Capac. with no risk of volume expansion. Platelet concentrate Volume of 1 u 50 ml. Stored at 20-24c for 5 days. 1 u increases platelet count 5-10,000/mm. ABO compatibility testing desirable but not necessary. Uses: All patients with pl count < 20,000. Surgery with pl count or= Blood volume in 24 h.  Coagulopathy and DIC.  Hypothermia.  Citrate toxicity. Ca.  Hyperkalemia.  Acid-base disordars. M.alk >M.acid. Fluid overload Blood grouping Group Antigen on RBC Antibody in serum Comment O Nil Anti-A,Anti-B Universal donor A A Anti-B B B Anti-A AB A&B Nil Universal recepient Blood grouping  Rh Rh-positive 85% Rh-negative 15% Rh+ve can rceive Rh+ve or –ve donor B. Rh-ve can receive Rh-ve donor B. O Rh-ve is the universal donor. PRCs Intraoperative guidelines PRCs preferred. Optimal utilization of blood bank resources. If volume needed,give crystalliod as well. Double check prior to transfusion. Large I.V cannula. 18G or more. Transfusion set with a filter. Do not use Ringer,dextrose or dextran as a diluent for PRCs.Only NS. Intraoperative guidelines Proper storage 4c. Blood warmer 37c. Close monitoring. In grave emergency larger cannula apply pressure (inflatable compressor) Autologous blood transfusion Collection of the patient’ own blood and re-infusing it when needed. Methods: Acute normovolemic hemodilution. Blood salvage. Preoperative donation. Blood salvage Advantages of ABT Eliminates risk of AIDS,hepatitis and other reactions. No need of typing and cross matching. Reduces the strain on blood resources. If used in the same day of collection,it contains platelets and intact clot.factors. Thank You