March 2012 lec


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March 2012 lec

  1. 1. FLUIDSAND ELECTROLYTES Nelia B. Perez RN, MSN IV Preceptor
  2. 2. Water overview*Water comprises about60% -70% of the totalbody weight*Varies with age weight gender
  3. 3. Water Loss ROUTES OF WATER LOSS-SENSIBLE -INSENSIBLE Urine Lungs Feces Sweat
  4. 4. Causes of Increased Causes of Increased Water Loss Water Gain•Fever •Increased sodium intake•Diarrhea •Increased sodium•Diaphoresis retention•Vomiting •Excessive intake of water•Gastric suctioning •Excess secretion of ADH•Tachypnea
  5. 5. Two Compartments of Fluid in the Body•Intracellular fluid (ICF) (70%) — fluid within cells - large amounts of K+, PO4--, Mg++•Extracellular fluid (ECF) (30%) — fluid outside cells - large amounts of Na+,Ca+,Cl-,HCO3-- - Includes intravascular(15%) and interstitial fluids(5%)
  6. 6. FLUIDS AND ELECTROLYTES There is a continuous exchange of fluid betweenthe fluid compartment , of these spaces only theplasma is directly influenced by the intake orelimination of fluid from the body.There is also the so called third space fluid shiftor “third spacing” where there is a loss of ECFinto a space that does not contribute to theequilibrium between ICF & ECF.
  7. 7. FLUIDS AND ELECTROLYTES “ Third spacing” occurs in:Ascites Burns Peritonitis Bowelobstruction Massive bleeding intobody cavity or joints
  8. 8. Electrolytes -An electrolyte is a substance, that when dissolved in water,gives a solution that can conduct electricity.
  9. 9. Importance of electrolytes-Maintain voltages across cell membranes-Carry electrical impulses to other cells-Found in blood or the human body in the form ofacids, bases or salts (Sodium, calcium, potasium,chlorine, magnesium, bicarbonate)-Conduct an electric current that transportsenergy thoughout the body
  10. 10. Major Electrolytes/Chief FunctionSodium — controls and regulates volume of body fluidsPotassium — chief regulator of cellular enzyme activity and water contentCalcium — nerve impulse, blood clotting, muscle contraction, B12 absorptionMagnesium — metabolism of carbohydrates and proteins, vital actions involving enzymesChloride — maintains osmotic pressure in blood, produces hydrochloric acidBicarbonate — body’s primary buffer systemPhosphate — involved in important chemical reactions in body, cell division and hereditary traits
  11. 11. Regulation of Body Fluid Compartments•Osmosis - the movement of water froman area of lower soluteconcentration to an area of highersolute concentration. •Semi-permeable membrane •membrane must be more permeable to water •a greater concentration of solutes on one side of the membrane
  12. 12. •Facilitated Diffusion•Requires a carrier molecule.•Lipid insoluble substances cannot cross the plasmamembrane (glucose).•ATP is not expended.•Movement of the particles is from an area of higherconcentration to an area of lower concentration.
  13. 13. •Active Transport movement of a substance across the cell membrane from an area of lower concentration to an area of higher concentration. ATP is expended. The sodium-potassium pump is an example of active transport.
  14. 14. Fluid Volume Deficit - Involves either volume or distribution of water orelectrolytes•Hypovolemia — deficiency in amount of water andelectrolytes in ECF with near normalwater/electrolyte proportions•Dehydration — decreased volume of water andelectrolyte change•Third-space fluid shift — distributional shift ofbody fluids into potential body spaces
  15. 15. Fluid Volume ExcessHypervolemia — excessive retention of waterand sodium in ECFOverhydration — above normal amounts ofwater in extracellular spacesEdema — excessive ECF accumulates in tissuespacesInterstitial-to-plasma shift — movement of fluidfrom space surrounding cells to blood
  16. 16. Types of IV SolutionsISOTONIC-solution has the same osmolality as the extracellularfluid. Examples: D5W ; Normal SalineHypertonic solutions have a higher concentration ofsolute and are more concentrated than extracellularfluids. Net movement intracellular to extracellular Examples : 3% saline; 5% salineHypotonic solutions have a lower concentration ofsolutes and is more dilute than extracellular fluid .Netmovement extracellular to intracellular Examples : 1/2 Normal Saline; 1/3 Normal Saline
  17. 17. Electrolyte ImbalancesSODIUM (Na+)  135-145 mEq/LFunctions •Maintains osmolality •Participates in active transport •Helps regulate body fluids •Participates in the action potentialHyponatremia:serum sodium level falls below 130mEq/L.Cells become swollen.Neurological Disturbances :cerebral edema,headache,lethargy,depression, confusion,convulsions,comaCardiovascular Disturbances: postural hypotension,shockHypernatremia: Serum sodium is more than 150mEq/L.Cells shrink.Complications:Osmotic Diuresis,cellular dehydration,circulation decreases
  18. 18. ElectrolytePOTASSIUMImbalancesmEq/L (K+): 3.5-5.0Functions •Transmission of nerve impulses •Resting membrane potential •Acid-base balance •Promotes myocardial, skeletal, and smooth muscle contractilityHypokalemia: <3 mEq/LCardiovascular: dysrhythmias, hypotension, digitalis toxicity, myocardialdamage, cardiac arrestNeurological: lethargy, confusion, depressionGastrointestinal : paralytic ileusSkeletal Muscle: weakness, flaccid paralysis, weakness of respiratorymuscles, respiratory arrestRenal System: decreased ability to concentrate urine, water loss, kidneydamageAcid-Base Balance: metabolic alkalosis
  19. 19. Hyperkalemia: serum value of >6 mEq/LNervous System : ParaesthesiaNeuromuscular: Muscle twitching, muscle weakness, paralysisCardiovascular : Bradycardia, Cardiac arrest
  20. 20. Electrolyte ImbalancesCALCIUM :8.5-10.5 mg/dl or 4.5-5.8 mEq/L Functions •Formation of bone and teeth •Contraction of muscle •Blood coagulation •Blocks sodium transport into the cell •Transmission of nervous impulses
  21. 21. •Hypocalcemia •Hypercalcemia<0.9 mmo/L ionized Calcium >12 mg/dL total Calcium or >1.5 mmol/L ionized Calcium•-Nervous System •-Neurological Manifestation • Paraesthesia • lethargy, confusion, coma•-Muscular System •-Skeletal Manifestations • Tetany, Laryngeal • deep bone pain; fractures • spasms •-Renal Manifestations:stones•-Cardiovascular System •-Gastrointestinal • congestive heart Manifestations failure • Constipation;anorexia • decreased cardiac • Nausea and Vomiting • output •-Cardiovascular Manifestations • cardiac • Shortened QT interval, dysrhythmias •Bradycardia • Cardiac arrest
  22. 22.  "the excessive loss of water and electrolytes from the body“ can be caused by losing too much fluid, not drinking enough water or fluids, or both.
  23. 23.  Infantsand children are more susceptible to dehydration than adults because of their smaller body weights and higher turnover of water and electrolytes. So are the elderly and those with illnesses
  24. 24.  dehydration occurs when losses are not replaced adequately and a deficit of water and electrolytes develop. These may occur in Vomiting or diarrhea Presence of an acute illness where there is loss of appetite and vomiting:  Pneumonia  DHF  Other Acute Ilnesses Excessive urine output, such as with uncontrolled diabetes or diuretic use Excessive sweating (sports) Burns
  25. 25.  Since diarrhea and vomiting are the most common causes of dehydration in children, the volume of fluid loss may vary from 5 ml/kg (normal) to 200 ml/kg Concentration of electrolytes lost also varies NaCl and K are the most common electrolytes lost through stools
  26. 26.  In order to diagnose the type of dehydration, you need to know the History and you must do a thorough physical examination We classify type of dehydration depending on the amount of water and electrolytes lost These are reflected by the signs and symptoms the child will present
  27. 27.  Dehydration is classified as no dehydration, some dehydration, or severe dehydration based on how much of the bodys fluid is lost or not replenished. When severe, dehydration is a life-threatening emergency
  28. 28. Assesment of Dehydration Graded according to the signs and symptoms that reflect the amount of fluid lost. There are usually no signs or symptoms in the early stages As dehydration increases, signs and symptoms develop. Initially, thirst, restlessness, irritability, decreased skin turgor, sunken eyes and sunken fontanelles. As more losses occur, these effects become more pronounced.
  29. 29. Signs of hypovolemic shock (SEQUELAE)1. diminished sensorium (lethargy)2. Lack of urine output3. Cool moist extremities4. A rapid and feeble pulse5. Decreased BP6. Peripheral cyanosis7. DEATH.
  31. 31. HOLIDAY-SEGAR METHODEstimates caloric expenditure in fixed weight categoriesAssumption  100 cal metabolized : 100 mL waterNot suitable for neonates < 14 days  Overestimates fluid needs
  32. 32. HOLIDAY-SEGAR METHOD BODY ml/kg/day ml/kg/hr Electrolytes WEIGHT (mEq/100ml fluid)First 10 kg 100 4 Na+ 3Second 10 kg 50 2 Cl- 2Each additional 20 1 K+ 2kg
  33. 33. BODY SURFACE AREA METHODAssumption: caloric expenditure is related to BSANot used in children < 10 kg
  34. 34. BSA METHOD STANDARD VALUES FOR USE IN BODY SURFACE AREA METHODComponent ValuesWater 1500 ml/m2/24 hrsNa+ 30-50 mEq/m2/24 hrsK+ 20-40 mEq/m2/24 hrs
  35. 35. BSA FormulaSurface area (m2) = ht (cm) x wt (kg) 3600
  36. 36. ICF & ECF COMPARTMENTSIn dehydration, there are variable losses from the extracellular and intracellular compartmentsPercentage of deficit is based on total duration of illness
  37. 37. Sources: Fluids & Electrolytes, Lippincott Williams & Wilkins Fluids & Electrolytes, Walters Kluwer Nelson’s Texbook of Pediatrics WHO department of child and adolescent development (Medline Plus) e/000982.htm