Fluid Electrolyte Balance by aeg54883

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									                                                                        Major Minerals

                                                           •   Sodium           • Major minerals –
                                                           •   Potassium          found in the body in
           Lecture 31                                                             amounts > 5 grams
                                                           •   Calcium
  Chapter # 12: Fluid & Minerals                           •   Chloride
                                                                                   – need 100 mg intake
                                                                                     or more per day
                                                           •   Phosphorus       • Trace minerals –
                       4/14/04
                                                           •   Magnesium          found in the body in
                                                           •   Sulfur             amounts < 5 grams
                                                                                   – need < 100 mg/day




   Fluid & Electrolyte Balance                                     Major Cellular Ions
• When a salt dissolves in water…it separates            • Intracellular – inside the cell
  into ionic particles which carry charge                  –   Potassium
• Cations – positively (+) charged electrolytes            –   Magnesium
  – Major cations                                          –   Phosphate
     • Hydrogen, sodium, potassium, magnesium, calcium
                                                           –   Sulfate
• Anions – negatively (-) charged electrolytes           • Extracellular – outside the cell
  – Major anions
                                                           – Sodium
     • Chloride, phosphorus, bicarbonate (HCO3)
                                                           – Chloride
• mEq (milliequivalents) - measure of
  electrolyte concentration                              • Water follows electrolytes.




                                                               Hormones Regulate Water
Blood Volume & Blood Pressure
                                                                       Balance
                                                         • ADH – antidiuretic hormone released by
• Water maintains blood volume                             pituitary gland
• Water influences blood pressure                           – Released in response to reduced blood
• Kidneys play major role in maintaining                      volume
  water balance                                             – Kidneys respond by reabsorbing water
                                                         • Renin - enzyme in kidney
• Kidney receives instructions from
                                                            – Released due to low blood pressure
  hormones
                                                            – Helps kidney to reabsorb sodium
                                                            – Water follows sodium
                                                            – Signals activation of angiotensin




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      Hormones Regulate Water                              Regulation of Fluid & Electrolyte
              Balance                                                  Balance
• Angiotensin (precursor angiotensinogen)                  • GI tract
  – Hormone involved in blood pressure                       – Ability to absorb water & minerals
    regulation                                               – ~ 8 liters of digestive fluid reabsorbed
  – Powerful vasoconstrictor – narrows blood                   each day
    vessels                                                  – Recycled fluids help maintain balance
• Aldoserone – release signaled by angiotensin             • Kidney
  – Hormone released from adrenal glands                     – Regulate water and minerals in plasma by
                                                               selective secretion and reabsorption
  – Causes kidneys to retain more sodium
                                                             – Aldosterone & ADH
  – Water follows sodium & less fluid excreted




Fluid & Electrolyte Imbalances                                  Blood Acid-Base Balance
   • Primary Causes               • Primary Electrolytes   • Measure of pH in blood - [H+] in body fluids
      –   Vomiting                  affected               • Body fluids classified
      –   Diarrhea                  – Sodium                 – Acid – H+ donor
      –   Heavy sweating            – Chloride               – Base – H+ acceptor
      –   Burns                     – Potassium            • Norm – 7.35 to 7.45
      –   Wounds                  • Replacement with         – pH < 6.8 and > 7.9 incompatible with life
                                    Oral Rehydration       • Acid-base regulation
                                    solutions                – Kidneys & lungs
                                                             – Metabolic & respiratory ability to get rid of
                                                               excess H+




            Sodium: Table Salt                                            Sodium Facts
• Table salt = sodium chloride                             • No DRIs established
  (NaCl)                                                     – Max considered ~ 2400 mg/day
   – ~ 40% sodium                                          • Minimum Requirement
• Adults generally eat ~ 3-6                                 – 500 mg / day
  gm sodium / day                                            – 95% absorption rate
   – That equates ~ 7-16 gm SALT                           • If we added no salt to our diet…our intake
     / day                                                   would be ~ 500 mg from natural foods
• One teaspoon salt contains                               • Losses – kidneys & sweat
  ~ 2 grams of sodium                                        – Aldosterone signals reabsorption in kidney
   – 1 gm salt = 400 mg sodium                               – Excess intake (> 2 gm / day) increases calcium
   – 1 teaspoon = 5 gram weight                                excretion




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     Sodium: Chief Functions                                         Sodium Imbalances
• Primary extracellular cation (Na+)                     • Hyponatremia                   • Hypernatremia
• Primary regulator of fluid volume                      • Low sodium in blood            • High sodium in blood
                                                           – Not usually due to               – Edema
• Helps maintain acid-base balance                           normal diet                      – Hypertension
  – Kidneys excrete H+ in exchange for Na+                 – Symptoms
                                                              •   Muscle cramps
• Essential for nerve signal transmission &                   •   Mental apathy
  muscle contraction                                          •   Loss of appetite
                                                              •   Weight loss
                                                              •   Poor growth




             Blood Pressure                                  Blood Pressure Guidelines
• Diastolic – lower number                               Category                    Systolic         Diastolic
  – Artery pressure when the heart is relaxed
  – Optimal diastolic pressure < 80 mm Hg
• Systolic – higher number                               Optimal                      < 120              < 80
  – pressure in the arteries when the heart actively
    pumps blood
  – Optimal systolic pressure < 120 mmHg                 Normal                       < 130              < 85
• Hypertension
  – Sustained systolic pressure > 140 mm                 High normal                 130-139            85-89
  – Sustained diastolic pressure > 90 mm




      Sodium & Hypertension                                   Food Sources of Sodium
• Sodium is not the only factor associated with          • Processed foods – usually highest amount
  high blood pressure                                      – Contributes 75% of sodium in the diet
  – Genetics & excess body weight
  – Poor intakes of calcium, potassium, magnesium          – Read the food labels for salt & sodium-based
  – Excess alcohol intake                                    preservatives
• Salt sensitivity found in ~ 10-15% of                  • Table salt used in cooking or from salt shaker
  individuals                                              – Contributes ~ 15% of sodium intake
  – Respond to a high salt intake with increased blood
    pressure                                             • Unprocessed foods – usually the least amount
  – Body weight correlates with salt sensitivity           – Contributes ~ 10% of sodium intake
• Best prevention                                          – Sodium naturally present in foods
  – Control weight, increase fruit & veg, control
    sodium intake




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    Examples of High Sodium Foods                                    Read: How to Cut Salt
                                                                                   Pg 400
•   Tomato juice                                                                        • Enhance flavor with
•   Salted crackers & snacks                                                              spices
•   Self-rising flours, baking powder
                                                                                            – Oregano
•   Instant products
                                                                                            – Garlic
•   Salad dressings
                                                                                            – Pepper
•   Bacon, ham, salad port & cured meats
•   Canned or dehydrated soups                                                          • Lemon juice
•   Pickled products
•   Seasoned salts
•   Soy sauce, teriyaki sauce, flavored vinegars
•   Olives, pickles, condiments




    Recommendations for BP Control                                         Chloride (Cl-)
• DASH diet – Dietary           • DASH DIET                •   Essential nutrient required in the diet
  Approaches to Stop               – 7-8 servings grains   •   Major anion (Cl-) in extracellular fluids
  Hypertension                     – 4-5 servings of veg   •   Mostly associated with sodium (Na+)
• High fruit / veg                 – 4-5 serving fruits    •   Part of stomach acid (HCl)
  diets low in fat                 – 2-3 servings low      •   Recommended intakes not established
                                     fat/nonfat dairy
• Increased intakes of                                     •   Minimum requirement 750 mg/day
                                   – ≤ 2 servings meat
     – Calcium                                             •   Dietary deficiency rare
                                   – 1-2 servings Nuts
     – Potassium                                           •   Physiological conditions increase loss
     – Magnesium                                               – Sweating, diarrhea, vomiting




             Potassium (K+) Facts                                        Potassium Facts
• Primary intracellular cation (K+)                        • Higher intakes associated with lower
• Abundant in all living cells – plant & animal              blood pressure and decreased calcium
• Role                                                       excretion
     –   Nerve transmission                                • Diets generally lower in K+ than Na+
     –   Muscle contraction
                                                             because rely on natural sources
     –   Important for heart beat regulation
     –   Acid-Base balance                                 • No RDA established
• Body absorbs 90% K+ consumed                             • Minimum requirement: 2000 mg/day
• Excretion primarily from kidneys (~ 80%)                 • Daily Value set at 3500 mg/day




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   Food Sources of Potassium                             Non-Food Sources of Potassium
• Milk & dairy products                                 • Salt substitutes
• Meats                                                   –   Morton salt substitute
• Fruits                                                  –   Morton seasoned salt sub
  – Bananas, oranges, grapefruit, raisins                 –   Morton Lite salt
                                                          –   Morton Nature’s Seasons
• Vegetables
                                                          –   Mrs. Dash, salt-free, original
  – Winter squash, potatoes, tomatoes
• Legumes
  – Kidney beans, pinto beans




         Potassium Imbalances                                  Magnesium (Mg++) Facts
• Hypokalemia               • Hyperkalemia              • > 50% found in bone (serves as storage)
  – Low potassium levels      – High potassium levels
• Causes                    • Causes                    • Low levels in extracellular fluids (1%)
  –   Diabetic acidosis
  –   Vomiting/diarrhea
                              – Medication              • Cofactor in enzyme functions including
                              – Kidney disease
  –   Diuretics                                           formation of ATP & protein synthesis
  –   Steroids              • Symptoms
  –   Laxatives               – Muscular weakness       • Partner with calcium
• Symptoms                    – Vomiting                  –   Bone & teeth mineralization
  –   Muscle weakness         – Heart arrhythmias
  –   Paralysis                                           –   Muscle contraction
  –   Confusion                                           –   Blood clotting
  –   Heart arrhythmias
                                                          –   Blood pressure reduction




           Magnesium Intakes                                    Magnesium Imbalance
• Food Sources              • RDA                       • Deficiency                     • Toxicity
  –   Nuts & legumes          – 400 mg/d (Men)            – Rare                            – Rare
                                                          – Alcohol abuse                   – Medication induced
  –   Whole grains            – 310 mg/d (Women)
                                                          – Protein malnutrition            – Kidney disease
  –   Dk green vegetables   • Upper level                 – Prolonged vomiting or
  –   Chocolate               – 350 mg/ NONFOOD             diarrhea
  –   Seafood                   magnesium / dat           – Some types of kidney
                                                            failure
  –   Hard Water
                                                        • Symptoms
                                                          – Tetany
                                                          – Weakness
                                                          – Confusion & hallucinations




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