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Intravenous Fluids Presented by: Dr. Meenal Aggarwal Moderator: Dr. S. Singh.

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Presentation on theme: "Intravenous Fluids Presented by: Dr. Meenal Aggarwal Moderator: Dr. S. Singh."— Presentation transcript:

1 Intravenous Fluids Presented by: Dr. Meenal Aggarwal Moderator: Dr. S. Singh

2 Basic Physiology Total body water: Pre mature infant : 80% of lean B.W. Term infant: 70 – 75% Adult male : 60% (more muscle) Adult female : 50% (more fat) TBW(60) : ECF (20)(plasma + interstitial fluid) + ICF (40)

3 In children : higher ECF (contributes to higher B.W.) T.B.W decreases with age (mainly d/t loss in ICF) Composition of body fluids:  ICF : K +, Mg 2+ Organic phosphate esters (ATP, Creatine phosphate, phospholipids)  ECF : Na +, Cl -, HCO3 - Compartments are separated by semi-permeable membrane Water freely passes through it and maintains an osmotic equilibrium Daily fluid requirement: Urine output + insensible losses (700ml)

4 Fluid Homeostasis in Body Act via Sympathetic nervous system Renin- Angio-aldo Natriureic hormones (ANP, BNP) Argenine vasopressin Sensed by Baroreceptors Carotid sinus, aortic arch Afferent glomerular arterioles Atria, ventricles Volume regulation Important for adequate tissue perfusion Effective circulating vol

5 Fluid Homeostasis in Body cont… Act via AVP Thirst Sensed by Osmoreceptors In hypothalamus (paraventricular, supraoptic nuclei) Osmoregulation Essential for cell function Plasma osmolarity Normal Plasma Osmolality = 2 X [Na + ] + [BUN/2.8] + [Glu/18] Normal value = mosm/Kg

6 Fluid Balance in Perioperative Period Goal: Euvolemia, normal oxygen carrying capacity and normal electrolyte distribution Challenges: because of: Fasting status Losses (bleeding, evaporation, 3 rd space losses) Effects of neuraxial anesthesia (sympatholysis) Ineffective thirst (d/t diminished alertness after GA/ sedation)

7 Assessment of Fluid Balance Preop History: Medical illness, preop vol status Surgery/ Intervention: Type of surgery, blood loss/ 3 rd space Anaesthesia: Type, duration, Fluid replacement given, BT, Type of monitoring, intra-op vital trends Current clinical condition: GPE: Weight, Skin and tongue, sensorium, pulse, BP Urine output : Should be >0.5-1ml/kg/hr Monitoring: Pleth, IBP, C.O. measurement, CVP, PCWP, TEE Lab: S.urea, S.creat, urinary Na, ABG (pH, lactate, Hct), VBG

8 Intra Venous Fluids I V FluidsCrystalloidsUnbalanced NS, 3% S, N/2 S D5, D10, D 25 Balanced Ringer Lactate Isolyte PColloidsGelatinsDextrans Starches (HES) Human Albumin

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10 Normal Saline (0.9% NaCl) Composition : Na meq/L, Cl meq/L Osmolarity: 308 mOsm/L (Isotonic), pH : 6.0 Distributed mainly in ECF, so very useful in hypovolemic shock Only 25% of the total fluid given remains intravascularly, 3-4 times volume of fluid lost is required for replenishment Indication: Salt and water deplation as in diarrhoea, vomiting, excessive sweating Tt of alkalosis (e.g. vomiting) with dehydration, May induce non anion gap hyperchloremic metabolic acidosis (as high chloride l/t dec plasma HCO3- content)

11 Normal Saline (0.9% NaCl) cont.. Hypovolemic shock Hyponatremia Initial fluid therapy in DKA Fluid challenge in pre-renal ARF Irrigation fluid Hypertonic Saline (3-7.5%): used in therapy of severe symptomatic hyponatremia, for resuscitation in patients of hypovolemic shock Caution: should be administered slowly, preferably through central venous catheter because can l/t hemolysis

12 Normal Saline (0.9% NaCl) cont.. Contraindication: Cautious use in HTN or preeclamptic patients, CHF pts, renal ds, cirrhosis If dehydration is preset along with hypokalemia (need to add K+ or else NS alone will aggravate K+ deficiency) Used cautiously in patients with renal derangements (chloride l/t decreased renal blood flow) Note: As it can l/t metabolic acidosis, should not be mistakenly interpreted as lactic acidosis in cases of impaired circulation

13 5% Dextrose Composition : Glucose 50 g/L (or 25 g/vac) Osmolarity: 252 mOsm/L (hypotonic), pH : 4.5 Only 8% of the total fluid given remains intravascularly (glucose gets metabolised when enters body, so free water) best for correcting intracellular dehydration Provides 170 Kcal/ L Indications: Tt of dehydration d/t inadequate water intake/ excessive water loss To provide calories Pre- and post-op replacement fluid

14 5% Dextrose cont… Tt and prevention of ketosis in starvation/ diarrhoea/ vomiting Correction of hypernatremia ( with frusemide) Contraindications: Cerebral edema/ Neurosurgical procedures/ Acute ischemic stroke Hypovolemic shock (also osmotic diuresis) Careful administration during hypernatremia Along with blood transfusion (hemolysis, clumping) Severe hyperglycemia/ uncontrolled DM

15 Ringer’s Lactate Composition : Na= 130mEq, K= 4mEq, Ca= 3mEq, Cl= 109mEq, lactate= 28 mEq per litre of RL Osmolarity: 274 mOsm/L (hypotonic), pH : 6.5 Most physiological fluid (can be given in large quantities without risk of electrolyte imbalance) Lactate is converted to HCO3 in the liver (correction of metabolic acidosis) Indications: Tt of severe hypovolemia rapidly with large fluid volume Diarrhoea induced hypovolemia with hypokalemic metabolic acidosis

16 Ringer’s Lactate cont… Postoperative fluid replacement In DKA, RL provides free water so corrects metabolic acidosis, also gives K (controvertial regarding lactate) Contraindications: Liver ds, severe hypoxia and shock (impaired lactate metabolism) In severe CHF with lactic acidosis Addison’s disease Even in severe metabolic acidosis (impaired lactate conversion) In vomiting or NG aspiration (metabolic alkalosis, RL worsens) Along with BT (Ca combines with citrate, forms clots), binds drugs (thiopentone, amphotericin, ampicillin, EACA)

17 Isolyte-P Composition : Glu = 50 g, Na= 25mEq, K= 20mEq, Cl= 22mEq, acetate= 23 mEq HPO4= 3 mEq, Mg= 3mEq per litre Designed to suit maintenance requirement of children (need more water) Can be used In adults where more water required (hypernatremia) Indications: Maintenance fluid in children and infants Excessive water loss/ inability to conc urine (DI) C/I: Hyponatremia, hypovolemic shock (less Na, More K, glucosuria) Renal failure

18 Plasma-lyte Composition : Na= 140 mEq, K= 5 mEq, Cl= 98 mEq, acetate= 27 mmol, gluconate 23 mmol, Mg= 1.5 mmol per litre Produces a metabolic alkalinizing effect (acetate and gluconate metabolize to CO2 and H2O using H+ ions) Indications: Fluid replacement For alkalinization Caution: CHF, Edema with Na retention Renal failure and metabolic alkalosis

19 Sterofundin Composition : Na= 145 mEq, K= 4 mEq, Cl= 127 mEq, Ca= 2.5 mmol, acetate= 24 mmol, Malate 5 mmol, Mg= 1 mmol per litre pH: , osmolarity= 309 mosm/L Indications: Fluid replacement in isotonic dehydration For alkalinization Caution: CHF, Edema with Na retention Renal failure/ hyperkalemia and metabolic alkalosis

20 Hydroxyethyl starches Modified natural polysaccharides similar to glycogen To delay α-amylase breakdown: natural starches are substituted with hydroxyethyl groups Classified into: high (hexastarch), medium (pentastarch) and low (tetrastarch) substitution. High Molar substitution delays degradation Plasma expanding effect depends on the concentration solution Advantages: High hemodilutional capacity Vascular resistance is reduced by lowering blood viscosity (beneficially influence tissue perfusion)

21 Hydroxyethyl starches cont… Disadvantages: Decrease levels of vWF and factor VIII activity, impair platelet function, induce platelet damage (apparent when >1500ml given within 24hrs) Renal dysfunction (hyperviscosity of urine in dehydrated pts) Pruritis may occur d/t extravascular deposition of starch Allergic reactions (although lowest c/f other colloids) Clearance takes over several weeks (although oncotic activity is lost after 24hrs)

22 Gelatins (Haemaccel) Produced by degradation of bovine collagen and chemical modifications Commercially available preparations: 3.5%-5.5% Adv: Average molecular weight: kD, small molecular weight, rapidly cleared from the bloodstream by glomerular filtration (80%) Volume effect % Do not accumulate in the body, have no dose limitations, almost no adverse effects on the kidneys

23 Gelatins cont… Disadv: Hemostasis could be impaired (interference with coagulation factors, disturbance in the quality of fibrin polymerization) Bovine origin (hypothetical potential of transmitting prion diseases) Most frequent incidence of allergic reactions (6 times c/f HES) Cleared rapidly so repeated infusions of gelatins are necessary to maintain adequate blood volume

24 Dextrans Biosynthesized from sucrose by the bacterium Leuconostoc mesenteroides Dextran 40 and dextran 70 (molecular weights of 40 and 70 kD) Adv: Molecules less than 50 kD are rapidly eliminated by the kidneys Decreases blood viscosity, improved microcirculatory blood and tissue perfusion Used by vascular and plastic surgeons to assist in keeping microvascular anastomosis patent Dextran 70: generally preferred for volume expansion Dextran 40: improve blood flow in the microcirculation

25 Dextrans cont… Disadv: Induces a dose-dependent hyperfibrinolysis, decreased levels of vWF and associated factor VIII (VIII:c) activity, Max daily dosing: 1.5g dextran/ kg body wt Coat red cells (interfere with cross matching, inc ESR) Impaired renal function (tubular obstruction, swelling, and vacuolization of tubular cells due to hyperviscous urine) Severe anaphylactic reactions (Prevention: dextran 1 (Promit), a low-molecular-weight hapten, administered few minutes before any dextran infusion)

26 Human Albumin Purified from pooled human plasma Commercially available as a 5% (iso-oncotic), 20% & 25% (hyperoncotic) solution Heated and sterilized by ultrafiltration, so risk of bacterial or viral disease transmission eliminated Functions of albumin: maintaining the plasma oncotic pressure, transport protein, plasma buffer Predictor of mortality risk in patients with acute and chronic illness (for each 2.5 g/L decrement in serum albumin concentration the risk of death increases by 24% to 56%) 5% albumin: 70% effective, effect lost in 12 hrs

27 Human Albumin cont… Uses: Acute restoration of an effective circulating volume due to hemorrhage Acute management of burns Hypoproteinemia Disadv: High cost Even detrimental in burns, hypoproteinemic pts. Allergic reactions (equal to HES)

28 Colloid vs Crystalloid For crystalloids: inexpensive, adverse effects are rare or absent, no renal impairment, minimal interaction with coagulation other than dilution, no tissue accumulation, no allergic reactions For colloids: much better volume-expanding properties, minor edema formation, improved microcirculation When compared neither type of fluid provided a survival benefit So in patient with hypovolemia d/t dehydration (uniform loss of ECF), crystalloids are benefecial In patients with hypovolemia secondary to hypoalbuminemia, colloids benefit the patient more.

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30 Balanced vs Unbalanced Solutions Large volume resuscitation with normal saline causes hyperchloremic metabolic acidosis (l/t organ hypoperfusion, increased morbidity, especially gastrointestinal, neurologic, renal damage, blood loss) Buffered formulations (RL, Isolyte P) maintain a higher plasma pH and less chloride load, fewer incidences of hyperchloremic metabolic acidosis, low concentration electrolytes l/t reduction in postoperative morbidity. Balanced crystalloid solutions are preferred in the perioperative period Colloids suspended in balanced solutions now available, are better

31 Maintenance Fluid therapy Normal ongoing losses in 70 kg man: ml/day Fluid to be given calculated acc to Holliday & Segar formula”4-2-1” Best maintenance fluid: balanced isotonic crystalloid (RL) untill the patient is NPO Best estimation of fluid requirement is made by weighing the patient daily Neuraxial anesthesia: Preloading with ml fluid appears to temporarily increase preload and C.O. without consistently increasing arterial B.P. or preventing hypotension.

32 Replacement Fluid therapy Bleeding/ 3 rd space loss/ Evaporation/ Sweating Assessment: Estimate/ measure + Clinical examination + laboratory data Type of fluid depends on the type of fluid lost or any electrolyte imbalance already present Rate of administration: Arbitrary, depends on severity of deficit (diff in case of hyper/hypo Na)

33 Post Operative Fluid Aim: BP > 100/70mm Hg, Pulse <120, Urine 30-50ml/hr, normal temperature, respiration, sensorium When to give: Usually for minor surgeries (no gut handling) started orally 4-6 hrs postop. In Major surgeries( no gut handling e.g. THR/ cardiac) hrs of IV fluids When intestinal resection: needs few days of IV fluids

34 Post Operative Fluid cont… Routine postop orders for fluids for 3 days: First 24 hrs: 2litre D5 or 1.5litre D ml NS (except neurosurgical patients, major surgeries) 2nd post op day: 2 litre D5 + 1litre NS 3 rd postop day: Same mEq KCl Modified according to individual case

35 Preferred fluid therapy In Vomiting: (Hypovol, HypoK, HypoCl, Meta alk) NS In Diarrhoea: (Hypovol, HypoNa, HypoK, HyperCl, Meta Acid) RL & NS CHF: Oedema d/t salt & water retention (HypoNa) Avoid Na rich fluids like RL & NS, Don’t chase urine output ARDS: Pulmonary edema d/t inc capillary permeability, Keep dry, maintain balance b/w diuretics and fluid to keep MAP >75-80mmHg In Neurological ds: maintain euvolemia (no hypotension) caution during mannitol, avoid hypotonic fluids and hyperglycemia (avoid D5), RL appropriate for small vol infusion, NS is ideal DKA: Glycosuria, osmotic diuresis, meta acid, K+ def, Mg & P def.

36 Preferred fluid therapy cont… DKA cont…: Initial therapy NS, If no hypotension and good urine output RL can be given, KCL can be added here, Further can switch to 0.45 Saline (acc to Na conc), once sugars below 250mg/dl D5 is to be used. In Renal Disease: Fluid restriction (Urine output + 500ml), in edematous pt so not chase the urine, salt restriction 2-3g/d, Avoid hyperkalemia (RL). In nephrotic NS prefered Pre-renal ARF: NS prefered In CRF: 5D or 10D prefered, limit fluid admn

37 THANK YOU


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