Fluid and electrolytes

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Fluid and electrolytes

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Fluid and electrolytes

  1. 1. FLUID & ELECTROLYTE BALANCE
  2. 2. BODY FLUIDS - 60% BODY WEIGHT <ul><li>WATER IS LARGEST SINGLE COMPONENT </li></ul><ul><li>60-70% of body weight. </li></ul><ul><li>45-50 % body weight in elderly </li></ul><ul><li>Variations based on age, gender & amt. of body fat </li></ul><ul><li>80% neonate is water* </li></ul>
  3. 3. Major Compartments for Fluids <ul><li>INTRACELLULAR FLUID (ICF) </li></ul><ul><li>Inside cell </li></ul><ul><li>Most of body fluid here - 40% weight </li></ul><ul><li>Decreased in elderly </li></ul><ul><li>EXTRACELLULAR FLUID (ECF) </li></ul><ul><li>Outside cell </li></ul><ul><li>Intravascular fluid - within blood vessels (5%) </li></ul><ul><li>Interstitial fluid - between cells & blood vessels (15%) </li></ul><ul><li>Transcellular fluid - cerebrospinal, pericardial , synovial </li></ul>
  4. 5. Distribution of solutes in body <ul><li>Electrolytes </li></ul><ul><li>Non-Electrolytes </li></ul><ul><li>- glucose, urea, uric acid </li></ul><ul><li>- proteins ( albumin ) </li></ul>
  5. 6. ELECTROLYTES <ul><li>Substance when dissolved in solution separates into ions & is able to carry an electrical current </li></ul><ul><li>CATION - positively charged electrolyte </li></ul><ul><li>ANION - negatively charged electrolyte </li></ul><ul><li>Cations must = Anions for homeostatsis to exist in each fluid compartment </li></ul><ul><li>Commonly measured in milliequivalents / liter (mEq/L) </li></ul>
  6. 8. MILLIEQUIVALENT (mEq) <ul><li>Unit of measure for an electrolyte </li></ul><ul><li>Describes electrolyte’s ability to combine & form other compounds </li></ul><ul><li>Equivalent weight is amount of one electrolyte that will react with a given amount of hydrogen </li></ul><ul><li>1 mEq of any cation will react with 1 mEq of an anion </li></ul>
  7. 9. DEFINITIONS <ul><li>SOLUTE - substance dissolved </li></ul><ul><li>SOLVENT - liquid in which the solute is dissolved </li></ul><ul><li>SELECTIVELY PERMEABLE MEMBRANES - found throughout body. cell membranes & capillary walls; allow water & some solutes to pass through them freely </li></ul>
  8. 11. METHODS OF FLUID & ELECTROLYTE MOVEMENT <ul><li>Diffusion </li></ul><ul><li>Osmosis </li></ul><ul><li>Active Transport </li></ul><ul><li>Filtration </li></ul>
  9. 12. DIFFUSION <ul><li>Process by which a solute in solution moves </li></ul><ul><li>Involves a gas or substance </li></ul><ul><li>Movement of particles in a solution </li></ul><ul><li>Molecules move from an area of higher concentration to an area of lower concentration </li></ul><ul><li>Evenly distributes the solute in the solution </li></ul><ul><li>Passive transport & requires no energy* </li></ul>
  10. 15. FACILITATED DIFFUSION <ul><li>Involves carrier system that moves substance across a membrane faster than it would with simple diffusion </li></ul><ul><li>Substance can only move from area of higher concentration to one of lower concentration </li></ul><ul><li>Example is movement of glucose with assistance of insulin across cell membrane into cell </li></ul>
  11. 17. OSMOSIS <ul><li>Movement of the solvent or water across a membrane </li></ul><ul><li>Involves solution or water </li></ul><ul><li>Equalizes the concentration of ions on each side of membrane </li></ul><ul><li>Movement of solvent molecules across a membrane to an area where there is a higher concentration of solute that cannot pass through the membrane </li></ul>
  12. 20. OSMOTIC PRESSURE <ul><li>Pull that draws solvent through the membrane to the more concentrated side (or side with solute ) </li></ul><ul><li>Amt. determined by relative number of particles of solute on side of greater concentration </li></ul><ul><li>Proportional to # of particles per unit volume solvent </li></ul>
  13. 21. COLLOID OSMOTIC PRESSURE OR ONCOTIC PRESSURE <ul><li>Special kind of osmotic pressure </li></ul><ul><li>Created by substances with a high molecular weight (like albumin) </li></ul>
  14. 22. ISOTONIC <ul><li>ISO - means alike </li></ul><ul><li>TONICITY - refers to osmotic activity of body fluids; tells the extent that fluid will allow movement of water in & out cell </li></ul><ul><li>Means that solutions on both sides of selectively permeable membrane have established equilibrium </li></ul><ul><li>Any solution put into body with the same osmolality as blood plasma - 0.9% sodium chloride or 5% glucose </li></ul>
  15. 23. HYPOTONIC HYPERTONIC <ul><li>Solution of lower osmotic pressure </li></ul><ul><li>Less salt or more water than isotonic </li></ul><ul><li>If infused into blood, RBCs draw water into cells ( can swell & burst ) </li></ul><ul><li>Solutions move into cells causing them to enlarge </li></ul><ul><li>Solution of higher osmotic pressure </li></ul><ul><li>3% sodium chloride is example </li></ul><ul><li>If infused into blood, water moves out of cells & into solution (cells wrinkle or shrivel) </li></ul><ul><li>Solutions pull fluid from cells </li></ul>
  16. 25. OSMOLALITY <ul><li>Measure of solution’s ability to create osmotic pressure & thus affect movement of water </li></ul><ul><li>Number of osmotically active particles per kilogram of water </li></ul><ul><li>Plasma osmolality is 280- 300* mOsm/ kg </li></ul><ul><li>ECF osmolality is determined by sodium </li></ul><ul><li>MEASURE used in clinical practice to evaluate serum & urine </li></ul>
  17. 26. Osmolality In Clinical Practice * <ul><li>Serum 280-300mOsm/kg; Urine 50-1400mOsm/kg </li></ul><ul><li>Serum osmolality can be estimated by doubling serum sodium </li></ul><ul><li>Urine specific gravity measures the kidneys’ ability to excrete or conserve water </li></ul><ul><li>Nl range 1.010 to 1.025 (compared to weight of distilled water with sp g of 1.000) </li></ul>
  18. 27. Other Lab Tests* <ul><li>BUN - blood urea nitrogen; made up of urea an end-product of protein metabolism; Nl 10-20 mg/dL ; inc. with GI bleeding, dehydration, inc. protein intake, fever, & sepsis; dec. with starvation, end-stage liver dx., low protein diet, expanded fluid vol. (as with pregnancy) </li></ul><ul><li>Creatinine - end product of muscle metabolism; better indicator of renal function; nl 0.7-1.5 mg/dL </li></ul><ul><li>Hematocrit - vol. % of RBCs in whole blood; m- 44-52%, f- 39-47% </li></ul>
  19. 28. ACTIVE TRANSPORT SYSTEM <ul><li>Moves molecules or ions uphill against concentration & osmotic pressure </li></ul><ul><li>Hydrolysis of adenosine triphosphate (ATP) provides energy needed </li></ul><ul><li>Requires specific “carrier” molecule as well as specific enzyme (ATPase) </li></ul><ul><li>Sodium, potassium, calcium, magnesium , plus some sugars, & amino acids use it </li></ul>
  20. 30. FILTRATION <ul><li>Movement of fluid through a selectively permeable membrane from an area of higher hydrostatic pressure to an area of lower hydrostatic pressure </li></ul><ul><li>Arterial end of capillary has hydrostatic pressure > than osmotic pressure so fluid & diffusible solutes move out of capillary </li></ul>
  21. 32. HYDROSTATIC PRESSURE <ul><li>Force of the fluid pressing outward against vessel wall </li></ul><ul><li>With blood not only refers to weight of fluid against capillary wall but to force with which blood is propelled with heartbeat </li></ul><ul><li>“ Fluid- pushing pressure inside a capillary”* </li></ul>
  22. 34. THIRD SPACING <ul><li>Large quantities of fluid from the intravascular compartment shift into the interstitial space; is inaccessible to the body </li></ul><ul><li>May be caused by lowered plasma proteins, increased capillary permeability & lymphatic blockage </li></ul><ul><li>Can be seen with trauma, inflammation, disease </li></ul>
  23. 35. PLASMA PROTEINS (Primarily Albumin) <ul><li>Affect serum osmolarity </li></ul><ul><li>Are main negatively charged intravascular fluid anions </li></ul><ul><li>Balance the positive charge of sodium in osmolarity </li></ul><ul><li>Create colloid osmotic pressure which pulls in & holds water in the vascular bed as well as pulling water from interstitial space into vascular bed - “water magnet”* </li></ul>
  24. 37. INTAKE FLUIDS OUT <ul><li>Ingested liquids 1500 </li></ul><ul><li>Water in foods 800* </li></ul><ul><li>Water from oxidation 300* </li></ul><ul><li>TOTAL 2600* </li></ul><ul><li>INSENSIBLE </li></ul><ul><li>Skin 600* </li></ul><ul><li>Lungs through expired air 300* </li></ul><ul><li>Feces 200 </li></ul><ul><li>Kidneys 1500* </li></ul><ul><li>TOTAL 2600* </li></ul>
  25. 39. THIRST <ul><li>Conscious desire for water </li></ul><ul><li>Major factor that determines fluid intake </li></ul><ul><li>Initiated by the osmoreceptors in hypothalamus that are stimulated by increase in osmotic pressure of body fluids to initiate thirst </li></ul><ul><li>Also stimulated by a decrease in the ECF volume </li></ul>
  26. 43. Neuro Endocrine Mechanisms <ul><li>Central Nervous System Ischemic Response- massive hemorrhage causes decrease in ECF volume & response that constricts afferent arterioles & decreases GFR </li></ul><ul><li>Baroreceptor Reflex - stretch receptors in large arteries that react to a decrease in ECF & respond by decreasing GFR </li></ul>
  27. 45. ADH (Antidiuretic Hormone) <ul><li>Made in hypothalamus; water conservation hormone </li></ul><ul><li>Stored in posterior pituitary gland </li></ul><ul><li>Acts on renal collecting tubule to regulate reabsorption or elimination of water </li></ul><ul><li>If blood volume decreases, then ADH is released & water is reabsorbed by kidney. Urine output will be lower but concentration will be increased. </li></ul>
  28. 49. ALDOSTERONE <ul><li>Produced by adrenal cortex </li></ul><ul><li>Released as part of RAA mechanism </li></ul><ul><li>Acts on renal distal convoluted tubule </li></ul><ul><li>Regulates water reabsorption by increasing sodium uptake from the tubular fluid into the blood but potassium is excreted </li></ul><ul><li>Responsible for reabsorption of sodium & water into the vascular compartment </li></ul>
  29. 52. RENIN <ul><li>Released by kidneys in response to decreased blood volume </li></ul><ul><li>Causes angiotensinogen (plasma protein) to split & produce angiotensin I </li></ul><ul><li>Lungs convert angiotensin I to angiotensinII </li></ul><ul><li>Angiotensin II stimulates adrenal gland to release aldosterone & causes an increase in peripheral vasoconstriction </li></ul>
  30. 56. You just ate 4 bags of potato chips so what would you expect? <ul><li>THIRST ? </li></ul><ul><li>ADH ? </li></ul><ul><li>OSMOLALITY ? </li></ul><ul><li>ALDOSTERONE ? </li></ul><ul><li>URINE OUTPUT ? </li></ul>
  31. 57. You decide to drink 5 gallons of water so what do you expect ? <ul><li>THIRST ? </li></ul><ul><li>ADH ? </li></ul><ul><li>OSMOLALITY ? </li></ul><ul><li>BLOOD VOLUME ? </li></ul><ul><li>RENAL BLOOD VOLUME ? </li></ul><ul><li>URINE OUTPUT ? </li></ul>
  32. 58. Quiz ???? <ul><li>1. Who has the highest body % of water? Infant? Adolescent? 50 year old? Elderly? </li></ul><ul><li>2. The chief cation of the ICF is Sodium? Chloride? Potassium? Phosphorus </li></ul><ul><li>Aldosterone is associated with an increase in - Urine output? Potassium in serum? Sodium in serum? BP? </li></ul>
  33. 59. More Questions ???? <ul><li>4. If you don’t drink any water or have lost a lot of water, what do you think will happen to: renal blood flow, renal BP, Glomerular filtration rate (GFR), ADH, Urine output </li></ul><ul><li>5. Your patient’s blood volume is low due to hemorrhage. What do you expect to see with: BP ? HR ? Skin hot or cool ? Urine output ? </li></ul>
  34. 60. Methods of Monitoring Fluid Balance !!!! <ul><li>BP - one of best tools to assess fluid vol </li></ul><ul><li>Review technique - ex. Cuff too small </li></ul><ul><li>Remember auscultatory gap </li></ul><ul><li>Orthostatic hypotension </li></ul>
  35. 61. Pulmonary Artery Catheter !!!! <ul><li>Measure PAP, PACWP, CO & CVP </li></ul><ul><li>Mean PAP = 10- 20 mm Hg </li></ul><ul><li>PACWP = nl 6-12 mm Hg </li></ul><ul><li>CO = HR X SV = 4-8 L/min </li></ul><ul><li>CVP = 5-10 cm H2O or 0-7mm Hg </li></ul>
  36. 62. IV Fluid Tonicity !!!! <ul><li>TONICITY </li></ul><ul><li>Hypotonic </li></ul><ul><li>Isotonic </li></ul><ul><li>Hypertonic </li></ul><ul><li>OSMOLALITY CELL </li></ul><ul><li>< 270 mOsm/kg Swelling </li></ul><ul><li>275-295 mOsm/kg Nothing </li></ul><ul><li>> 300 mOsm/kg Shrinking </li></ul>
  37. 63. Dehydration !!!! <ul><li>Disturbance of water balance </li></ul><ul><li>output greater than input </li></ul><ul><li>Decrease in body water below normal </li></ul><ul><li>May be the result of – pure water depletion </li></ul><ul><li>- pure salt depletion </li></ul><ul><li>- mixed </li></ul>
  38. 64. INTAKE & OUTPUT <ul><li>Low INTAKE </li></ul><ul><li>Oral fluids - including ice, gelatin, etc. </li></ul><ul><li>Parenteral fluids </li></ul><ul><li>Tube feedings with flushes </li></ul><ul><li>Catheter irrigants that are not withdrawn </li></ul><ul><li>More OUTPUT </li></ul><ul><li>Urine output </li></ul><ul><li>Liquid feces </li></ul><ul><li>Vomitus </li></ul><ul><li>NG drainage </li></ul><ul><li>Excessive sweating </li></ul><ul><li>Wound drainage </li></ul><ul><li>Draining fistula </li></ul><ul><li>Rapid or labored RR </li></ul>
  39. 65. 1-Pure water Depletion <ul><li>Occurs when water intake is not there and there is no loss of salts in the secretions. </li></ul><ul><li>CAUSES --- very weak or ill patient </li></ul><ul><li>- comatosed patient </li></ul><ul><li>- mentally upset </li></ul><ul><li>- dysphagia </li></ul><ul><li>- total inavailability of water </li></ul>
  40. 66. Pathophysiology and Effects <ul><li>No water intake , use up of water stores , continuous obligatory water loss. </li></ul><ul><li>ECF becomes hypertonic </li></ul><ul><li>Water flows from ICC to ECC and causes cellular dehydration. </li></ul><ul><li>There is Thirst, Oliguria due to the release of ADH. BP may drop in late stage. </li></ul>
  41. 67. Biochemical findings <ul><li>ECF is hypertonic </li></ul><ul><li>Blood urea may be slightly raised </li></ul><ul><li>Plasma volume decreases in late stage </li></ul><ul><li>Urine volume is scanty with raised specific gravity </li></ul><ul><li>Death occurs when water loss amounts to 15% of body weight. </li></ul>
  42. 68. 2- Pure Salt Depletion <ul><li>Due to the loss of fluids of high Na or Cl content and replacement done by salt deficient fluids. </li></ul><ul><li>CAUSES : excessive sweating, loss of GI fluids, urinary loss of Na, diuretics. </li></ul>
  43. 69. Pathophysiology and effects <ul><li>ECF becomes hypotonic </li></ul><ul><li>Decreased release of ADH and thus diuresis </li></ul><ul><li>Results in decrease in plasma and interstitial fluid volume. </li></ul><ul><li>Hypotonicity of ECF results in water entry into the cells and further fall in ECF volume. </li></ul>
  44. 70. <ul><li>NO thirst </li></ul><ul><li>Marked weakness and fainting </li></ul><ul><li>Loss of interstitial fluid causes sunken eyes and loss of skin elasticity </li></ul><ul><li>Decreased cardiac output and fall in BP. </li></ul><ul><li>Decreased glomerular filtration results in raised urea level. </li></ul>
  45. 71. Biochemical findings <ul><li>ECF hypotonic </li></ul><ul><li>Low plasma volume </li></ul><ul><li>Haemoconcentration </li></ul><ul><li>Decreased plasma sodium </li></ul><ul><li>Raised blood urea </li></ul><ul><li>---------------------------------------- </li></ul><ul><li>Death by oligaemic shock and peripheral circulatory failure. </li></ul>
  46. 72. 3-FLUID VOLUME DEFICIT <ul><li>Hypovolemia or FVD is result of water & electrolyte loss </li></ul><ul><li>Compensatory mechanisms include: Increased sympathetic nervous system stimulation with an increase in heart rate & cardiac contraction; thirst; plus release of ADH & aldosterone </li></ul><ul><li>Severe case may result in hypovolemic shock or prolonged case may cause renal failure </li></ul>
  47. 73. CAUSES OF FVD <ul><li>Abnormal GI fluid loss such as N&V or drainage of GI tract </li></ul><ul><li>Abnormal fluid loss from skin such as high temperature or burns </li></ul><ul><li>Increased water vapor from the lungs such as hyperpnea </li></ul><ul><li>Conditions that increase renal excretion of fluids such as diuretics & hypersomolar tube feedings </li></ul><ul><li>Decrease in fluid intake </li></ul><ul><li>Third-space shift such as ascites or trauma </li></ul>
  48. 74. LAB VALUES IN FVD <ul><li>INCREASE IN: HEMATOCRIT nl 44*-52*% M nl 39*-47% F BUN nl 10*-20 mg/dl URINE SPECIFIC GRAVITY nl 1.010*-1.025* </li></ul>
  49. 75. SIGNS & SYMPTOMS OF FVD <ul><li>Dry mucous membranes </li></ul><ul><li>Weight loss -mild at 2%,moderate at 5%, & severe deficit at 8% </li></ul><ul><li>Orthostatic hypotension & increase in pulse rate </li></ul><ul><li>Body temperature usually subnormal </li></ul><ul><li>Flat neck veins & decrease in CVP </li></ul><ul><li>Decreased urinary output & altered sensorium </li></ul>
  50. 76. NURSING MANAGEMEMT OF FVD <ul><li>Monitoring I&O on a regular schedule depending on the patient </li></ul><ul><li>If urine output is below 30 mL / hr. notify the physician </li></ul><ul><li>May check urine specific gravity q 8hrs. </li></ul><ul><li>Weigh patient daily at the same time & recognize that a change of 2.2 lbs. represents a loss of 1000 mL </li></ul><ul><li>Monitor skin turgor, oral membranes, lab </li></ul>
  51. 77. FLUID VOLUME EXCESS <ul><li>Hypervolemia or FVE is result of expansion of fluid compartment from an increase in total sodium content </li></ul><ul><li>Kidney receives signal to save sodium & water to compensate for cirrhosis, CHF, renal failure, excessive Na-containing fluid </li></ul><ul><li>Labs may show dec.:hematocrit, serum Na, serum osmolality, urine sp. Gr; inc. BUN </li></ul>
  52. 78. SIGNS & SYMPTOMS OF FVE <ul><li>SOB & orthopnea </li></ul><ul><li>Edema & weight gain </li></ul><ul><li>Distended neck veins & tachycardia </li></ul><ul><li>Increased blood pressure </li></ul><ul><li>Crackles & wheezes </li></ul><ul><li>Maybe ascites & pleural effusion </li></ul><ul><li>Increase in CVP </li></ul>
  53. 79. NURSING MANAGEMENT OF FVE <ul><li>Monitor I & O plus monitor for physical signs of hypervolemia </li></ul><ul><li>Check for edema & weigh patient daily </li></ul><ul><li>Restrict sodium intake as prescribed </li></ul><ul><li>Limit intake of fluids </li></ul><ul><li>Watch for signs of potassium imbalance </li></ul><ul><li>Monitor for signs of pulmonary edema </li></ul><ul><li>Place patient in semi-Fowler’s position </li></ul>
  54. 80. Water Intoxication !!!! <ul><li>Excess fluid moves from EC space to IC space </li></ul><ul><li>Happens with SIADH, rapid infusion of hypotonic IV sol or tap water as NG irrigant or enemas; can happen with psychogenic polydipsia ( may drink 12-18 L/day ) </li></ul><ul><li>Findings Serum NA < 125 mEq/L Serum Osmolality < 280 mOsm/kg </li></ul>
  55. 81. ISOTONIC SOLUTIONS <ul><li>0.9% Sodium Chloride Solution </li></ul><ul><li>Ringer’s Solution </li></ul><ul><li>Lactated Ringer’s Solution </li></ul>
  56. 82. HYPOTONIC SOLUTIONS <ul><li>5% DEXTROSE & WATER </li></ul><ul><li>0.45% SODIUM CHLORIDE </li></ul><ul><li>0.33% SODIUM CHLORIDE </li></ul>
  57. 83. HYPERTONIC SOLUTIONS <ul><li>3% SODIUM CHLORIDE </li></ul><ul><li>5% SODIUM CHLORIDE </li></ul><ul><li>WHOLE BLOOD </li></ul><ul><li>ALBUMIN </li></ul><ul><li>TOTAL PARENTERAL NUTRITION </li></ul><ul><li>TUBE FEEDINGS </li></ul><ul><li>CONCENTRATED DEXTROSE (>10%) </li></ul>
  58. 84. SODIUM (NA + ) <ul><li>DOMINANT EXTRACELLULAR ELECTROLYTE </li></ul><ul><li>CHIEF BASE OF BLOOD </li></ul><ul><li>NL SERUM LEVEL 135-145 mEq/L </li></ul>
  59. 85. SODIUM (NA)* <ul><li>Main extracellular fluid (ECF) cation </li></ul><ul><li>Helps govern normal ECF osmolality </li></ul><ul><li>Helps maintain acid-base balance </li></ul><ul><li>Activates nerve & muscle cells </li></ul><ul><li>Influences water distribution (with chloride) </li></ul>
  60. 86. SODIUM (NA + ) <ul><li>SODIUM AFFECTS FLUID VOLUME & CONCENTRATION IN ECF </li></ul><ul><li>IS REGULATED BY : Aldosterone Renal blood flow Renin secretion Antidiuretic hormone (ADH) due to its effect on water Estrogen Carbonic anhydrase enzyme </li></ul>
  61. 88. HYPERNATREMIA <ul><li>Serum Na + level > 148 mEq/L serum osmolality > 295 mOsm/kg & urine sp gr > 1.030 with nl kidneys </li></ul><ul><li>Collaborative management tries to gradually lower serum sodium by *infusion of 0.45% NaCl *monitoring U/O & serum sodium levels *administering fluids carefully *restricting sodium intake </li></ul><ul><li>The thirsty person will not get this !!!! </li></ul>
  62. 89. HYPONATREMIA <ul><li>Serum Na + < 135 mEq/L (patient may be asymptomatic until level drops below 125) </li></ul><ul><li>Collaborative management seeks to correct cause & give sodium with caution due to possible rebound fluid excess by : *infusing isotonic saline in IV fluids *restricting oral & IV water intake *increasing dietary sodium *monitoring for signs of hypervolemia </li></ul>
  63. 90. POTASSIUM (K + ) <ul><li>DOMINANT INTRACELLULAR ELECTROLYTE </li></ul><ul><li>PRIMARY BUFFER IN CELL </li></ul><ul><li>NL SERUM LEVEL 3.5-5.5 *mEq/L </li></ul>
  64. 91. POTASSIUM (K)* <ul><li>Dominant cation in intracellular fluid (ICF) </li></ul><ul><li>Regulates cell excitability </li></ul><ul><li>Permeates cell membranes, thereby affecting cell’s electrical status </li></ul><ul><li>Helps control ICF osmolality & ICF osmotic pressure </li></ul>
  65. 92. POTASSIUM (K + ) <ul><li>MOVEMENT INFLUENCED BY :Changes in pH Insulin Adrenal hormones Changes in serum sodium </li></ul><ul><li>IMPORTANT IN: Neuromuscular irritability Intracellular osmotic activity Acid-base balance </li></ul>
  66. 93. HYPERKALEMIA <ul><li>K + > 5.5 mEq/L </li></ul><ul><li>Dangerous due to potential for fatal dysrhythmias, cardiac arrest </li></ul><ul><li>Major cause is renal disease </li></ul><ul><li>EKG shows tall, peaked T waves & dysrthythmias </li></ul><ul><li>Beware of pseudohyperkalemia due to prolonged tourniquet, hemolysis of blood, sampling above KCl infusion </li></ul>
  67. 94. HYPERKALEMIA TX <ul><li>Watch EKG for fatal dysrthymias or cardiac arrest </li></ul><ul><li>Collaborative management may include: Calcium to counteract effect on heart Sodium bicarbonate to alkalinize fluids Hemodialysis or peritoneal dialysis Cation exchange resins (Kayexalate) by mouth or enema Small dose of insulin & dextrose Restrict dietary K + </li></ul>
  68. 95. HYPOKALEMIA <ul><li>K + < 3.5mEq/L </li></ul><ul><li>Most common type of electrolyte imbalance </li></ul><ul><li>Major cause is increase renal loss most often associated with diuretics </li></ul><ul><li>EKG shows dysrhythmias, flattened T wave </li></ul><ul><li>Can increase the action of digitalis </li></ul><ul><li>NEVER GIVE K + IV PUSH & ALWAYS DILUTE IN IV FLUIDS </li></ul>
  69. 96. HYPOKALEMIA TX <ul><li>Correct the cause </li></ul><ul><li>Oral or IV administration of potassium </li></ul><ul><li>Salt substitutes containing K + </li></ul><ul><li>Foods high in potassium : bananas, pears, dried apricots; fruit juices; tea, cola beverages; milk; meat, fish; baked potato; dried beans (cooked); ANYTHING THAT TASTES GOOD LIKE CHOCOLATE !! </li></ul>
  70. 98. ACID-BASE BALANCE <ul><li>Governed by the regulation of hydrgen ion (H + ) concentration in the body </li></ul><ul><li>pH = negative logarithm of the H + concentration </li></ul><ul><li>Acids - proton donors & give up H + </li></ul><ul><li>Bases - H + acceptors </li></ul><ul><li>Acidic - inc. in concentration of H + </li></ul><ul><li>Basic - dec. in concentration of H + </li></ul>
  71. 100. HENDERSON - HASSELBALCH EQUATION <ul><li>Expresses that the ratio of base to acid or HCO 3 - to H 2 CO 2 * ( 20: 1) determines the pH </li></ul><ul><li>pH < 7.35 ACIDOSIS </li></ul><ul><li>pH > 7.45 ALKALOSIS </li></ul>
  72. 102. ACID-BASE REGULATORY MECHANISMS <ul><li>CHEMICAL BUFFER SYSTEMS - bicarbonate, phosphate, protein, hemoglobin </li></ul><ul><li>LUNGS - carbonic acid broken down into CO 2 & H 2 O </li></ul><ul><li>KIDNEYS - increasing or decreasing bicarbonate ions </li></ul>
  73. 108. Arterial Blood Gases (ABGs) <ul><li>pH 7.35-7.45 </li></ul><ul><li>PaCO 2 35-45 mm Hg </li></ul><ul><li>Pa O 2 80-100 mm Hg </li></ul><ul><li>O 2 sat. 95-99% </li></ul><ul><li>HCO 3 - 22-26mEq/L </li></ul>
  74. 109. ACID-BASE PARAMETERS <ul><li>ACID </li></ul><ul><li>pH <7.35 </li></ul><ul><li>PaCO2 >45 </li></ul><ul><li>HCO3 <22 </li></ul><ul><li>BASE </li></ul><ul><li>pH >7.45 </li></ul><ul><li>PaCO2 <35 </li></ul><ul><li>HCO3 >26 </li></ul>
  75. 110. Which way will the scale tip???* <ul><li>Acidosis vs. Alkalosis </li></ul>
  76. 111. Respiratory Acidosis* <ul><li>pH < 7.35 </li></ul><ul><li>PaCO 2 > 45mm Hg </li></ul><ul><li>Due to inadequate alveolar ventilation </li></ul><ul><li>Tx aimed at improving ventilation </li></ul><ul><li>R espiratory O pposite </li></ul>
  77. 112. Respiratory Alkalosis* <ul><li>pH > 7.45 </li></ul><ul><li>PaCO 2 < 35mm Hg </li></ul><ul><li>Due to alveolar hyperventilation & hypocapnia </li></ul><ul><li>Tx depends on underlying cause </li></ul>
  78. 113. Metabolic Acidosis* <ul><li>pH < 7.35 </li></ul><ul><li>HCO 3 < 22mEq/L </li></ul><ul><li>Due to gain of acids or loss of base (like excessive GI loss from diarrhea ) </li></ul><ul><li>May have associated hyperkalemia </li></ul><ul><li>Tx aimed at correcting metabolic defect </li></ul><ul><li>M etabolic E ven </li></ul>
  79. 114. Metabolic Alkalosis* <ul><li>pH > 7.45 </li></ul><ul><li>HCO 3 > 26 mEq/L </li></ul><ul><li>Due to loss of acid or gain of base (most common is vomiting or gastric suction ) </li></ul><ul><li>Hypokalemia may produce alkalosis </li></ul><ul><li>Tx aimed at underlying disorder </li></ul>
  80. 115. EVALUATING ABGs* <ul><li>1. List pH, P a CO 2 , & HCO 3 - </li></ul><ul><li>2. Compare to normals & rate as ACID, BASE OR NORMAL . Write A (acid), B (base), or N (normal) or think ROME </li></ul><ul><li>3. Circle any two letters that are the SAME to tell IMBALANCE. </li></ul><ul><li>pH 7.10 P a CO 2 80mmHg HCO 3 - 25mEq/l ???? IMBALANCE ???? </li></ul><ul><li>Look at P a O 2 & S a O 2 for oxygenation </li></ul>
  81. 116. ABG ASSESSMENT* <ul><li>36 yo pt. complains of acute SOB, R sided pleuritic pain </li></ul><ul><li>pH 7.50 </li></ul><ul><li>P a CO 2 29 mmHg </li></ul><ul><li>P a O 2 60 mmHg </li></ul><ul><li>HCO 3 - 24 mEq/l </li></ul><ul><li>S a O 2 78% </li></ul><ul><li>? Meaning ? </li></ul><ul><li>32 yo pt. with drug OD & breathing 5 times / minute </li></ul><ul><li>pH 7.25 </li></ul><ul><li>P a CO 2 61 mmHg </li></ul><ul><li>P a O 2 74 mmHg </li></ul><ul><li>HCO 3 - 26 mEq/l </li></ul><ul><li>SaO 2 89% </li></ul><ul><li>? Meaning ? </li></ul>
  82. 117. ABGs* <ul><li>70 year old diabetic with hx of not taking insulin </li></ul><ul><li>pH 7.26 </li></ul><ul><li>PaCO 2 42 </li></ul><ul><li>HCO 3 17 </li></ul><ul><li>???? </li></ul><ul><li>58 year old pt. With CHF for 6 mos. & placed on digoxin & Lasix </li></ul><ul><li>pH 7.48 </li></ul><ul><li>PaCO 2 45 </li></ul><ul><li>HCO 3 26 </li></ul><ul><li>???? </li></ul>
  83. 118. FASTING BLOOD GLUCOSE 70-110mg/dl <ul><li>GLUCOSE levels are controlled by insulin & glucagon </li></ul><ul><li>While fasting glucose levels are low & glucagon is secreted </li></ul><ul><li>Glucagon breaks glycagon to glucose in liver & blood glucose rises </li></ul><ul><li>Glucose goes up after eating & insulin is secreted </li></ul><ul><li>Insulin attaches to insulin receptors in cells which drive glucose into these target cells to be metabolized </li></ul><ul><li>Blood glucose levels go down </li></ul>
  84. 119. HYPER HYPOGLYCEMIA <ul><li>CAUSED BY: DIABETES MELLITUS ; Acute stress response; Cushing’s syndrome; Pheochromocytoma; Chronic renal failure;Diuretic therapy; Corticosteroid therapy </li></ul><ul><li>CAUSED BY: INSULIN OVERDOSE; Insulinoma; Hypothyroidism; Hypopituitarism; Addison’s dx; Extensive liver dx; Starvation </li></ul>
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