FLUID AND ELECTROLITE

FLUID AND ELECTROLITEKen wirastutiFLUIDS TOTAL BODY WATER 60% of total body weight in males.55% of total body weight in females.75% of total body weight in infants.

WATER SOURCES & LOSSESsources Exogenous 2 3 l per day Endogenous ( metabolic water )350 ml/d Losses -Sensible urine & faeces -Insensible sweat & resp water input = water output Crystalloids.

Colloids.Types of FluidsCrystalloidsAqueous solutions of low mol.wt. ions(salts)With or without glucose.

Sodium is the major osmotically active particle.

Crystalloid replacement shoud be 3 to 6 times the volume of lost blood.CrystalloidsNormal saline(NS).Lactated Ringers solution(LR).5% dextose in water (D5W).Ringers acetate.D5LR.D5 NS.D5 NS.Hypertonic saline(HS)3%.

6Normal Saline0.9% NaCl (isotonic) 308 mOsm/L.Na 154 mEq/L. Cl 154 mEq/L.PH 5.7Uses: Hyponatremia. Brain injuryLarge quantity--hyperchloremic metabolic acidosis.

The predominant effect of volume resuscitation with crystalloid fluids is to expand the interstitial fluid volume rather than the plasma volumeLactated Ringer LROsmolarity 273 mOsm/LNa 130 Cl 109 mEq/LK 4 Ca 3 mEq/LLactate 28 mEq/LThe most physiological solution.Lactate is converted into HCO3 in the liver

Ringer AcetateAcetate 28 mEq/LMetabolism 2.5-4 times faster than lactate(in muscles).

GLUCOSE 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 as the predominant effect of volume resusscitation with gluc 5 % is to expand the intracellular volume ( cellular oedema )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).Hypertonic Saline HS 3%Osmolarity 1026 mOsm/L.Na 513 Cl 513 mEq/L.It expands plasma volume by the increase in IV oncotic pressure(fluids move from IC fluid).More effective than crystalloids.Uses: Severe hyponatremia. Early treatment of hypovol. shock. Side effects: hypernatremia,hyperchloremia,hypokalemia and coag. Problems.

ColloidsSolutions 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 CrystalloidsColloids 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 ColloidsBlood derived: Human albumin.

Synthetic * Starches. * Gelatins. *Dextrans.Human Albumin5% (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.StarchesHetastarch 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.GelatinsHaemagel Relatively cheap.No effect on coagulation or on crossmatching.High incidence of allergic reactions.DextransDextran 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 isch.limb (dextran 40).DextransDisadvantages: 1- Bleeding tendency. 2- Interfere with biood grouping and crossmatching. 3- Rare anaphylactic reactions. 4- Dextran 40 can precipitate in renal tubules leading to RF. 18Electrolite disturbancePrinciples of Electrolyte DisturbancesImplies an underlying disease process Treat the electrolyte change, but seek the causeClinical manifestations usually not specific to a particular electrolyte change, e.g., seizures, arrhythmiasPrinciples of Electrolyte DisturbancesClinical manifestations determine urgency of treatment, not laboratory valuesSpeed and magnitude of correction dependent on clinical circumstancesFrequent reassessment of electrolytes requiredELECTROLYTES METABOLISMNa is the main extracellular cation 135-145 mEq/ litre Avearge daily requirements is about 5 gm daily equivalent to 5oo ml of isotonic saline 0.9 % K is the main intracellular cation 3.5-5.5 mmol/l A normal daily intake 1mmol/kgTotal normal serum level of Ca 8.5-10.5 mg/dlIonized 3.5-4.5 mg/dl

Hypoalbuminemia causes total hypocalcemia without affecting the physiologically active ionized CaHypokalemiaK < 3.5 mmol/LEtiology alkalosis, diuresis, dka, ngs, n/v, hypomagnesemiaManifestations life threatening arrhythmiasDeficit poorly estimated by serum levels23Which one of the following ECG changes is least likely to occur with hypokalemia?ST-T segment depressionT wave inversionAV Blocks (2nd and 3rd degree)PVCsU wavesQT prolongationHypokalemiaTreat aggressively in severe metabolic acidosisCorrect hypomagnesemia ECG monitoring with emergent administrationAllowable maximum iv dose per hour controversialLife threatening arrhythmias: 10 mmols/ 20 minutesKCL 20 mmols/hr Central IV or 20 mmol/ PO q1 hourKCL 10 mmols/hr peripheral IV (Inefficient)HyperkalemiaK>5.5 mmol/dLEtiology renal failure, acidemia, cell death, drugs(ACE/Succinylcholine) Manifestations arrhythmias: peaked t waves, QRS widening, sine wave.

Hyperkalemia TreatmentUrgency of treatment- clinical manifestationsStop intakeGive calcium for cardiac toxicityShift K+ into cell glucose + insulin, NaHCO3, inhaled 2-agonist (high dose)Remove from body diuretics, sodium polystyrene sulfonate, dialysisHyponatremiaNa < 135 mmol/LHypo-osmolar hyponatremia Euvolemic (SIADH,Hypothyroidism)Hypovolemic (Diuretics, Adrenal Insuff.)Hypervolemic (CHF, Cirrhosis, NS)Normo- or hyperosmolar hyponatremiaPseudohyponatremiaManifestations neurologic (brain edema)28Hyponatremia TreatmentHypovolemic Na give normal saline, rule out adrenal insufficiencyHypervolemic Na increase free H2O lossEuvolemic hyponatremia Restrict free water intakeIncrease free water lossNormal or hypertonic salineCorrect slowly due to possibility of demyelinating syndromes29HypernatremiaNa > 145 mmol/LCauses: diarrhea, vomiting, diuresis, thirst, diabetes insipidusManifestations- neurologic Na = 160 mmol, 70 kg male1 L D5W changes Na by 4 mmol/LH2O deficit (L) = [ 0.6 wt (kg) ] [ observed Na/140 - 1 ] = 6 Liter Free H2OUrine Osmolality > 500 mOsmol/kg extrarenal or osmotic diuresis, < 300 mOsmol/kg diabetes insipidusHypernatremia TreatmentProvide intravascular volume replacementConsider giving one-half of free H2O deficit initiallyReduce Na cautiously: 0.5-1.0 mmol/L/hrSecondary neurologic syndromes with rapid correction

Other Electrolyte DeficitsCa, PO4, Mg May produce serious but nonspecific cardiac, neuromuscular, respiratory, and other effectsAll are primarily intracellular ions, so deficits difficult to estimateTitrate replacement against clinical findings

Other Electrolyte DisordersHypocalcemiaCalcium chloride or gluconateBolus + continuous infusionAlbumin correction is uselessHypercalcemiaRehydration with normal salineLoop diureticsOther Electrolyte DisordersHypophosphatemiaPO4 < 2.5 mg/dLReplacement iv for level < 1 mg/dL HypomagnesemiaEmergent administration over 510 minsLess urgent administration over 1060 minsThank you for your attention