3 HOMEOSTASIS Normal hydration balance Intake equals output Quantities of water and electrolytes entering body are equivalent to quantities exitingIntakeAll water entering into bodyDigestive system (liquids, solids, metabolic sources)OutputAll water excreted from the bodyLungs, kidneys, skin, intestines
5 HOMEOSTASIS (CONT.) Maintaining a constant stable internal environment Fluid levels decrease:ADH secretedKidney tubules reabsorb more water back into blood and excrete less urineThirst sensation stimulates one to drinkRestoration of fluid volumes to normal valuesFluid levels riseKidneys activated to excrete more urineWater shifts from one compartment to another maintaining balance
6 BODY WATER Most abundant substance in human body 60% of total body weight in adult male52% of total body weight in adult femaleActs as universal solvent for bodily solutesSolventFluid in which another substance will dissolveSoluteSubstance that is dissolved in a solutionSolutionLiquid containing dissolved substances
7 FLUID COMPARTMENTS Two major fluid compartments Intracellular fluid compartmentIncludes all water (and electrolytes) enclosed by cell membraneConstitutes 75% of all body water40-45% of body weightExtracellular fluid compartmentComposed of all fluids found outside of the cellConstitutes 25% of all body water15-20% of body weight
8 FLUID COMPARTMENTS (CONT.) Divisions of extracellular fluid compartmentInterstitial fluidFluid between the cells and outside of the blood vesselsConstitutes 17.5% of extracellular fluidIntravascular fluidFluid found within circulatory systemWater within blood vesselsConstitutes 7.5% of extracellular fluid
9 FLUID COMPARTMENTS (CONT.) Transcellular fluidSpecialized fraction of extracelluar fluidSeperated from other extracellular fluids by layer of epitheliumIncludes:Cerebrospinal fluidIntraoccular fluidSynovial fluidSerous fluid within body cavities
10 DEHYDRATION Definition Loss of water and electrolytes Etiology: Gastrointestinal lossesVomitingDiarrheaMalabsorption disorders
16 DEHYDRATION Management Ensure adequate airway and ventilation Administer oxygen and monitor delivery with oximetric monitoringMonitor cardiac rate and rhythmEstablish IV isotonic crystalloid solutionLR/NSml/hrFluid challenge
18 EdemaEdema is the accumulation of water in the interstitial space due to disruption in the forces and mechanisms that normally keep net filtration at zero.Mechanisms of edemaA decrease in plasma oncotic forceAn increase in hydrostatic pressureIncreased capillary permeabilityLymphatic channel obstruction
19 Edema Can be local or within a certain organ system May be generalized Sprained ankle vs. pulmonary edemaMay be generalizedWater in interstitial spaces is not available for metabolic processes in the cells.
23 ELECTROLYTES General Information Substance that dissociate into charged particles when placed in waterIonsMolecules that possess a positive or negative chargeTotal number of positve ions equals total number of negative ionsElectrical neutrality lawCations have positive chargeAnions have negative chargeElectrolytes measured in milliquivalents per liter (mEq/L)
24 NONELECTROLYTESSolutes that dissolve in water, but have no electrical chargeNonelectrolytes do not release ionsSolid molecules are usually measured in grams and milligramsExamples:GlucoseAmino acidsUrea
29 ESSENTIAL CATIONS (CONT.) Magnesium (Mg+)Necessary for biochemical functionsCoenzyme in protein and carbohydrate metabolismAid in transport of sodium and potassium across cell membranesNormal value: mEq/LHypermagnesemia: elevated serum potassiumHypomagnesemia: reduced serum potassium
31 ESSENTIAL ANIONS Chloride (Cl-) Regulates fluid balance and renal functionFollows sodiumParticipates in acid/base balanceNormal value: mEq/LBicarbonate (HC03-)Chief buffer in bodyNeutralizes hydrogen (H+) ion and other organic acidsNormal value: 21-25mEq/LPhosphate (HP04-)Important for energy storesIntracellular buffer, aids renal function
84 OSMOSIS Definition and description Fluid compartments are seperated by semipermeable membranes (pores)Semipermeable membranesSpecialized biological membrane that surrounds cell and encloses blood vessel wallsCertain materials are allowed to pass through freelyOxygenCarbon dioxideWaterLarger compounds are restrictedProteinsLarge sugars
85 OSMOSIS (Cont.) Definition and description Movement of a solvent (H20) through a semipermeable membrane from an area of lesser (solute) concentration to an area of greater solute concentration in an attempt to equalize the concentration on both sides of a membraneForm of diffusion
86 OSMOSIS (Cont.) Description If one side of membrane has a higher solute concentrate than the other, a pressure gradient exists (pulling force) and water moves from the side of lower concentration to higher concentration until both sides are equalConcentration of water to solute molecules should remain balanced on both sides of membrane
88 OSMOTIC PRESSURE Definition and description Osmotic pressure control Pressure established as a result of unequal solute concentration across a semipermeable membraneOsmotic pressure controlChief factor controlling water distributionWater moves toward the highest solute concentrationSodium is most prevalent extracellular cation exerting osmotic force
89 OSMOTIC PROPERTIES Determined by number of particles in solution Not by weight or molecular chargeGreater number of solute particles in solutionGreater osmotic pressure of that solutionGreater difference of dissolved particles on opposite sides of membraneOsmolarityConcentation of osmotically active particles in solutionMeasured in milliosmolesPlasma contains 300 milliosmoles/liter
90 COLLOID OSMOTIC PRESSURE (ONCOTIC PRESURE) Fraction of total osmotic pressure exerted by colloids (proteins)Proteins are large molecules that do not readily cross capillary walls or cell membranesColloid osmotic pressure is immensely important in maintaining fluid within vascular spaceAlbumin/Chief plasma protein
91 TONICITY OF BODY FLUIDS Definition TonicityNumber of particles present per unit volumeIsotonic solutionSolution containing same concentration of dissolved particlesHypotonic solutionSolution having a solute concentration lower than that of bodily cellsHypertonic solutionSolution having a concentration greater than that of bodily cells
94 ACTIVE TRANSPORTMovement of molecules against a concentration gradientFaster than diffusionRequires energy and utilizes carrier moleculesExample: Sodium/Potassium pump
95 DIFFUSION Definition and description Molecules or ions in solutions move from regions of higher concentration to regions of lower concentration until both sides of membrane are equalProcess results in uniform distribution of diffusing substanceMovement is opposite that of water movementFacilitated diffusionRequires “helper proteins” to cross the membraneRequires energy and must follow a gradientExample: Insulin/glucose relationship
96 Intravenous TherapyThe introduction of fluids and other substances into the venous side of the circulatory systemReplaces blood lost through hemorrhageElectrolyte or fluid replacementIntroduction of medications directly into the vascular system
97 Blood and Blood Components PlasmaMostly water with proteins and other dissolved elementsFormed ElementsErythrocyteLeukocyteThrombocyte
98 Fluid ReplacementThe most desirable fluid for blood loss replacement is whole blood.Blood is often fractionatedPacked cells and plasmaBlood must be typed and cross-matched to prevent a severe allergic reaction.
99 Fluid Replacement Transfusion reaction Occurs when there is a discrepancy between the blood type of the patient and donorSigns and symptoms of a transfusion reactionChills, hives, hypotension, palpitations, tachycardia, flushing of the skin, headaches, loss of consciousness, nausea, vomiting, or shortness of breath
100 Fluid Replacement Transfusion reaction (cont.) Treatment IMMEDIATELY stop the transfusionSave the substance being transfusedRapid IV infusion crystalloid solutionAdministration of mannitol (Osmotrol), diphenhydramine (Benadryl), or furosemide (Lasix)Be alert for signs of fluid overload and congestive heart failure.
102 Hemoglobin-Based Oxygen-Carrying Solutions (HBOCs) Commonly referred to as “blood substitutes”Compatible with all blood typesDo not require blood typing, testing, or cross-matchingHBOCs do not contain RBCs, so there is no concern for Rh incompatibility because the Rh factor of blood is found on the outer surface of the RBC.Initial studies on HBOCs have been disappointing
103 ColloidsColloids remain in intravascular spaces for an extended period of time and have oncotic force.Plasma protein fraction (Plasmanate)Salt-poor albuminDextranHetastarch (Hespan)
104 CrystalloidsCrystalloid solutions are the primary compounds used in prehospital careNon-protein solutionsNormal SalineLactated RingersClassified according to tonicityIsotonic solutionsHypertonic solutionsHypotonic solutions
105 CrystalloidsAwareness of the effects of hypertonic, isotonic, and hypotonic solutions on red blood cells.
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