Acid base balance + fluid balance


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Acid base balance + fluid balance

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  • 1. Respiratory acidosis [more CO2 indicates acidosis] pH - <7.35 PaCO2 – excess CO2 HCO3- low carbonic acid [HCO3 levels are lower than normal indicates acidosis 2. Respiratory alkalosis [more CO2 being exhaled than normal results in alkalosis] pH - > 7.45 PaCO2 – low CO2 HCO3 - high carbonic acid 3. Metabolic acidosis pH - <7.35 PaCO2 - normal HCO3 – low bicarbonate 4. Metabolic alkalosis pH - > 7.45 PaCO2 - normal HCO3- high bicarbonate
  • Body fluids made up of electrolytes Electrolyte is an element Separates into ions – cations (positive, Na+, K+, Ca+) and anions (negative, Chloride, bicarbonate [HCO3} Minerals (Example: Iron and Zinc) Initiate nerve responses Initiate muscle contractions Metabolize nutrients in foods Regulate electrolyte balance Regulate hormone production Strengthen bones Too much or too little causes serious consequences
  • Concentration gradient = the difference between the two concentrations (i.e. movement of oxygen and CO2 between the alveoli and blood vessels in the lungs
  • Treatments will be directed at eliminating the cause
  • Sodium Problem is because Na is found is most body fluids Loss of sodium without loss of body fluids, sodium becomes diluted in ECF Vomiting, suctioning, diarrhea, burn, diuretics, SIADH
  • Most common cause is over-hydration with D5W Post-op fluid replacement Heart failure Cirrhosis
  • 1. Fluid moves outside cell – cells dehydrated Signs and symptoms Dry skin Dry mucus membranes, tongue Low BP Fever CNS - Agitated Restless Lab values – Na high, Urine – high Specific gravity Thirst Causes Diabetic ketoacidosis - Diabetes Insipidus - caused by a lack of response to ADH.  commonly called pituitary DI .   It is also known as central or neurogenic DI .  posterior pituitary can be destroyed by - tumors, infections, head injuries, infiltrations, and various inheritable defects
  • Note - hypokalemia [ aLKalosis associated with Low K] Potassium Acquired in the diet Excreted in urine Must be replaced daily Function Maintains acid-base balance Participates in metabolism Causes Poor intake – patient is not eating Renal loss (diuretics) GI loss (diarrhea, vomiting) Signs and symptoms Tachycardia Low BP Flaccid muscles EKG – Flattened T wave Treatment Oral replacement if preferable, could be IV Low K+ could lead to digoxin toxicity due to low circulating volume
  • Too much Potassium – less common than hypokalemia and More dangerous Common Causes Renal failure (Rarely occurs in person with normal renal function) Signs and symptoms Bradycardia (high K+ suppresses SA node) Tremors, twitching N/V EKG changes – Peaked T, PVC’s, arrhythmias Treat Kayexalate Insulin – pushes K+ back into the little house Dialysis
  • 1. Calcium 1. Neuromuscular activity 2. Cardiac activity 3. Blood coagulation Etiology – how does this happen Surgical hypothyroidism Pancratitis Renal failure Vit. D deficiency 3. Signs and Symptoms 1. Hyperactive reflexes 2. Hypotension 3. Positive Trousseaus 4. Positive Chevostek’s 5. Prolonged QT interval Trousseau’s Sign - a test for latent tetany in which carpal spasm is induced by inflating a sphygmomanometer cuff on the upper arm to a pressure exceeding systolic blood pressure for 3 minutes. A positive test may be seen in hypocalcemia and hypomagnesemia. Treatment Oral route is safer IV: calcium gluconate over 5-10 minutes Monitor EKG
  • Etiology Ca is stored in the bones Essential for neuromuscular activity, cardiac activity, blood coagulation Cause of hypercalcemia Hyperparathyriodism (parathyroids control Ca levels by production of calcitonin Paget’s disease (bone metabolism disease) Excessive Vit. D intake Prolonged immobility Paget's disease is a metabolic bone disease that involves bone destruction and re-growth, which results in deformity. Signs and symptoms Anorexia, N/V Coma Flaccid muscles Arrhythmias and cardiac arrest Treatment Fluids IV aredia, pamidronate
  • Magnesium Intracellular reactions and utilization of ATP CNS transmissions Cardiovascular tone Etiology Pancreatitis Cirrhosis GI losses Alcoholism Calcium gluconate administration Treatment of Diabetic ketoacidosis S/S Increased deep tendon reflexes Chvostek’s/Trousseaus signs pos EKG changes Pre-ecclampsia Condition that is not fully understood Occurs in about 8% of pregnancies Symptoms are: high BP, edema in extremities, protein in urine, aches, blurred vision and possible seizures Treat – with Magnesium sulphate IV – acts as vasodialator (causes flushing and hypotension)
  • Etiology (not common) Renal disease Hypercalcemia Adrenal insufficiency Signs and symptoms Flushing Low BP, slow pulse Respiratory depression Hypoactive reflexes Increase in Mg depresses skeletal muscles and nerve function Most common cause is renal failure Bradycardia due to depression of acetylcholine Decreased respirations,coma, ECG changes
  • #2 – Because of the retention of CO2, the clinical profile of respiratory acidosis includes decreased pH < 7.35, PaCO# - > 42 with varying levels of HCO3 related to hypoventilation Option #1 is respiratory alkalosis which occur because of blowing off CO2 resulting in decreased level of acid and retention or production of HCO3 resulting in pH > 7.45 Option #3 is Metabolic acidosis because of high H+ or loss of HCO3 often caused by diarrhea, or retention related to kidney failure Option #4 – metabolic alkalosis caused by increased HCO3, or loss of H+, related to vomiting, gastric suction or loss of upper GI secretions
  • Acid base balance + fluid balance

    1. 1. Acid Base and Fluid Balance Dr.Nasim Ullah Siddiqui
    2. 2. Homeostasis <ul><li>A delicate balance of fluids, electrolytes, and acids and bases is required to maintain good health. This balance is called Homeostasis: The bicarbonate buffering system is an important buffer system in the acid-base homeostasis of living things, including humans. As a buffer, it tends to maintain a relatively constant plasma pH and counteract any force that would alter it. </li></ul><ul><li>In this system, carbon dioxide (CO 2 ) combines with water to form carbonic acid (H 2 CO 3 ), which in turn rapidly dissociates to form hydrogen ion and bicarbonate (HCO 3 - ).The reaction is catalyzed by the enzyme carbonic anhydrase . </li></ul><ul><li>When carbon dioxide dissolves in water, it can do so as a gas dissolved in water or by reacting with water to produce carbonic acid. </li></ul>
    3. 3. <ul><li>Any disturbance of the system will be compensated by a shift in the chemical equilibrium according to Le Chatelier's principle . For example, if the blood gained excess hydrogen ions (a process called acidosis ), some of those hydrogen ions would shift to carbon dioxide, minimizing the increased acidity. </li></ul><ul><li>This buffering system becomes an even more powerful regulator of acid-base homeostasis when it is coupled with the body's capacity for respiratory compensation , in which breathing is altered to modify the amount of CO 2 in circulation. In the above example, the body could increase breathing ( respiratory alkalosis ) to expel the excess CO 2 , pulling still more hydrogen ions toward the production of carbon dioxide. The process could continue until the excess acid is all exhaled . </li></ul>
    4. 4. When carbon dioxide dissolves in water, it can do so as a gas dissolved in water or by reacting with water to produce carbonic acid. In the cells of your body, the rate of carbonic acid production is accelerated by the enzyme carbonic anhydrase when excess hydrogen ions are added to the system the equilibrium is shifted to the left. This means that some of the added hydrogen ions will react with the bicarbonate ions to produce carbonic acid and the carbonic acid will dissociate into carbon dioxide and water as shown below.   Carbonic acid is known as a weak acid because it partially dissociates into the positive Hydrogen ions and negative bicarbonate ions. When hydrogen ions are removed from the reaction, the equilibrium will shift to the right. More carbon dioxide will combine with water and more carbonic acid will be produced and more hydrogen ions and bicarbonate ions will be produced.
    5. 5. Regulation of Acid-Base Balance <ul><li>Lower concentration of H+, more alkaline, higher pH </li></ul><ul><li>The pH is also a reflection of the balance between CO2 (regulated by lungs) and bicarb (regulated by kidneys) </li></ul><ul><li>Normal H+ level is necessary to </li></ul><ul><ul><li>Maintain cell membrane integrity </li></ul></ul><ul><ul><li>Maintain speed of cellular enzymatic actions </li></ul></ul>
    6. 6. Chemical Regulation <ul><li>Carbonic acid-bicarbonate buffer system is the first to react to change in the pH of ECF </li></ul><ul><li>H+ and CO2 concentrations are directly related </li></ul><ul><li>ECF becomes more acidic, the pH decreases, producing acidosis </li></ul><ul><li>ECF receives more base substances, the pH rises, producing alkalosis </li></ul><ul><li>Lungs primarily control excretion of CO2 resulting from metabolism </li></ul><ul><li>Kidneys control excretion of hydrogen and bicarb </li></ul>
    7. 7. Acid-Base Balance <ul><li>Acid-Base balance is: </li></ul><ul><ul><li>the regulation of HYDROGEN ions. </li></ul></ul>
    8. 8. pH <ul><li>The acidity or alkalinity of a solution is measured as pH . </li></ul><ul><li>The more acidic a solution, the lower the pH. </li></ul><ul><li>The more alkaline a solution , the higher the pH. </li></ul><ul><li>Water has a pH of 7 and is neutral. </li></ul><ul><li>The pH of arterial blood is normally between 7.35 and 7.45 </li></ul>
    9. 9. Hydrogen ions <ul><li>The more Hydrogen ions, the more acidic the solution and the LOWER the pH. </li></ul><ul><li>The lower Hydrogen concentration, the more alkaline the solution and the HIGHER the pH. </li></ul>
    10. 10. Buffer Systems <ul><li>Regulate pH by binding or releasing Hydrogen </li></ul><ul><li>Most important buffer system: </li></ul><ul><ul><li>Bicarbonate-Carbonic Acid Buffer System </li></ul></ul><ul><ul><ul><li>(Blood Buffer systems act instantaneously and thus constitute the body’s first line of defense against acid-base imbalance) </li></ul></ul></ul>
    11. 11. Respiratory Regulation <ul><li>Lungs </li></ul><ul><ul><li>help regulated acid-base balance by eliminating or retaining carbon dioxide </li></ul></ul><ul><ul><li>pH may be regulated by altering the rate and depth of respirations </li></ul></ul><ul><ul><li>changes in pH are rapid, </li></ul></ul><ul><ul><ul><ul><ul><li>occurring within minutes </li></ul></ul></ul></ul></ul><ul><ul><li>normal CO 2 level </li></ul></ul><ul><ul><ul><li>35 to 45 mm Hg </li></ul></ul></ul>
    12. 12. Renal Regulation <ul><li>Kidneys </li></ul><ul><ul><li>the long-term regulator of acid-base balance </li></ul></ul><ul><ul><li>slower to respond </li></ul></ul><ul><ul><ul><li>may take hours or days to correct pH </li></ul></ul></ul><ul><ul><li>kidneys maintain balance by excreting or conserving bicarbonate and hydrogen ions </li></ul></ul><ul><ul><li>normal bicarbonate level </li></ul></ul><ul><ul><ul><li>22 to 26 mEq/L. </li></ul></ul></ul>
    13. 13. Factors Affecting Balance <ul><li>Age </li></ul><ul><ul><li>especially infants and the elderly </li></ul></ul><ul><li>Gender and Body Size </li></ul><ul><ul><li>amount of fat </li></ul></ul><ul><li>Environmental Temperature </li></ul><ul><li>Lifestyle </li></ul><ul><ul><li>stress </li></ul></ul>
    14. 14. Acid-Base Imbalances <ul><li>Respiratory Acidosis </li></ul><ul><li>Respiratory Alkalosis </li></ul><ul><li>Metabolic Acidosis </li></ul><ul><li>Metabolic Alkalosis </li></ul>
    15. 15. Respiratory acidosis pH ↓ PaCO2 ↑ HCO3 ↓ Respiratory alkalosis pH ↑ PaCO2 ↓ HCO3 ↑ Metabolic acidosis pH ↓ PaCO2 HCO3 ↓ Metabolic alkalosis pH ↑ PaCO2 HCO3 ↑
    16. 16. Respiratory Acidosis <ul><li>Mechanism </li></ul><ul><ul><li>Hypoventilation or Excess CO 2 Production </li></ul></ul><ul><li>Etiology </li></ul><ul><ul><li>COPD </li></ul></ul><ul><ul><li>Neuromuscular Disease </li></ul></ul><ul><ul><li>Respiratory Center Depression </li></ul></ul><ul><ul><li>Late ARDS </li></ul></ul><ul><ul><li>Inadequate mechanical ventilation </li></ul></ul><ul><ul><li>Sepsis or Burns </li></ul></ul><ul><ul><li>Excess carbohydrate intake </li></ul></ul>
    17. 17. Respiratory Acidosis (cont) <ul><li>Symptoms </li></ul><ul><ul><li>Dyspnea, Disorientation or coma </li></ul></ul><ul><ul><li>Dysrhythmias </li></ul></ul><ul><ul><li>pH < 7.35, PaCO 2 > 45mm Hg </li></ul></ul><ul><ul><li>Hyperkalemia or Hypoxemia </li></ul></ul><ul><li>Treatment </li></ul><ul><ul><li>Treat underlying cause </li></ul></ul><ul><ul><li>Support ventilation </li></ul></ul><ul><ul><li>Correct electrolyte imbalance </li></ul></ul><ul><ul><li>IV Sodium Bicarbonate </li></ul></ul>
    18. 18. Respiratory Alkalosis <ul><li>Risk Factors and etiology </li></ul><ul><ul><li>Hyperventilation due to </li></ul></ul><ul><ul><ul><ul><ul><li>extreme anxiety, stress, or pain </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>elevated body temperature </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>overventilation with ventilator </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>hypoxia </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>salicylate overdose </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>hypoxemia (emphysema or pneumonia) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>CNS trauma or tumor </li></ul></ul></ul></ul></ul>
    19. 19. Respiratory Alkalosis (cont) <ul><li>Symptoms </li></ul><ul><ul><li>Tachypnea or Hyperpnea </li></ul></ul><ul><ul><li>Chest pain </li></ul></ul><ul><ul><li>Light-headedness, syncope, coma, seizures </li></ul></ul><ul><ul><li>Numbness and tingling of extremities </li></ul></ul><ul><ul><li>Difficult concentrating, tremors, blurred vision </li></ul></ul><ul><ul><li>Weakness, paresthesias, tetany </li></ul></ul><ul><ul><li>Lab findings </li></ul></ul><ul><ul><ul><ul><li>pH above 7.45 </li></ul></ul></ul></ul><ul><ul><ul><ul><li>CO2 less than 35 </li></ul></ul></ul></ul>
    20. 20. Respiratory Alkalosis (cont) <ul><li>Treatment </li></ul><ul><ul><ul><li>Monitor VS and ABGs </li></ul></ul></ul><ul><ul><ul><li>Treat underlying disease </li></ul></ul></ul><ul><ul><ul><li>Assist client to breathe more slowly </li></ul></ul></ul><ul><ul><ul><li>Help client breathe in a paper bag </li></ul></ul></ul><ul><ul><ul><li>or apply rebreather mask </li></ul></ul></ul><ul><ul><ul><li>Sedation </li></ul></ul></ul>
    21. 21. Metabolic Acidosis <ul><li>Risk Factors/Etiology </li></ul><ul><ul><li>Conditions that increase acids in the blood </li></ul></ul><ul><ul><ul><li>Renal Failure </li></ul></ul></ul><ul><ul><ul><li>DKA </li></ul></ul></ul><ul><ul><ul><li>Starvation </li></ul></ul></ul><ul><ul><ul><li>Lactic acidosis </li></ul></ul></ul><ul><ul><li>Prolonged diarrhea </li></ul></ul><ul><ul><li>Toxins (antifreeze or aspirin) </li></ul></ul><ul><ul><li>Carbonic anhydrase inhibitors - Diamox </li></ul></ul>
    22. 22. Metabolic Acidosis (cont) <ul><li>Symptoms </li></ul><ul><ul><li>Kussmaul’s respiration </li></ul></ul><ul><ul><li>Lethargy, confusion, headache, weakness </li></ul></ul><ul><ul><li>Nausea and Vomiting </li></ul></ul><ul><ul><li>Lab: </li></ul></ul><ul><ul><ul><li>pH below 7.35 </li></ul></ul></ul><ul><ul><ul><li>Bicarb less than 22 </li></ul></ul></ul><ul><li>Treatment </li></ul><ul><ul><li>treat underlying cause </li></ul></ul><ul><ul><li>monitor ABG, I&O, VS </li></ul></ul>
    23. 23. Metabolic Alkalosis <ul><li>Risk Factors/Etiology </li></ul><ul><ul><li>Acid loss due to </li></ul></ul><ul><ul><ul><li>vomiting </li></ul></ul></ul><ul><ul><ul><li>gastric suction </li></ul></ul></ul><ul><ul><li>Loss of potassium due to </li></ul></ul><ul><ul><ul><li>steroids </li></ul></ul></ul><ul><ul><ul><li>diuresis </li></ul></ul></ul><ul><ul><li>Antacids (overuse of) </li></ul></ul>
    24. 24. Metabolic Alkalosis (cont) <ul><li>Symptoms </li></ul><ul><ul><li>Hypoventilation (compensatory) </li></ul></ul><ul><ul><li>Dysrhythmias, dizziness </li></ul></ul><ul><ul><li>Paresthesia, numbness, tingling of extremities </li></ul></ul><ul><ul><li>Hypertonic muscles, tetany </li></ul></ul><ul><ul><li>Lab: pH above 7.45, Bicarb above 26 </li></ul></ul><ul><ul><ul><ul><li>CO2 normal or increased w/comp </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Hypokalmia, Hypocalcemia </li></ul></ul></ul></ul><ul><li>Treatment </li></ul><ul><ul><li>I&O, VS </li></ul></ul><ul><ul><li>give potassium </li></ul></ul><ul><ul><li>treat underlying cause </li></ul></ul>
    25. 26. Interpreting ABGs <ul><li>1. Look at the pH </li></ul><ul><ul><ul><li>is the primary problem acidosis (low) or alkalosis (high) </li></ul></ul></ul><ul><li>2. Check the CO2 ( respiratory indicator) </li></ul><ul><ul><ul><li>is it less than 35 (alkalosis) or more than 45 (acidosis) </li></ul></ul></ul><ul><li>3. Check the HCO3 ( metabolic indicator) </li></ul><ul><ul><ul><li>is it less than 22 (acidosis) or more than 26 (alkalosis) </li></ul></ul></ul><ul><li>4. Which is primary disorder (Resp. or Metabolic)? </li></ul><ul><ul><ul><li>If the pH is low (acidosis), then look to see if CO2 or HCO3 is acidosis (which ever is acidosis will be primary). </li></ul></ul></ul><ul><ul><ul><li>If the pH is high (alkalosis), then look to see if CO2 or HCO3 is alkalosis (which ever is alkalosis is the primary). </li></ul></ul></ul><ul><ul><ul><li>The one that matches the pH (acidosis or alkalosis), is the primary disorder. </li></ul></ul></ul>
    26. 27. Compensation <ul><li>The Respiratory system and Renal systems compensate each other </li></ul><ul><ul><li>attempt to return the pH to normal </li></ul></ul><ul><li>ABG’s show that compensation is present when </li></ul><ul><ul><li>the pH returns to normal or near normal </li></ul></ul><ul><li>If the non primary system is in the normal range (CO2 35 to 45) (HCO3 22-26), then that system is not compensating for the primary. </li></ul><ul><li>For example: </li></ul><ul><ul><li>In respiratory acidosis (pH<7.35, CO2>45), if the HCO3 is >26, then the kidneys are compensating by retaining bicarbonate. </li></ul></ul><ul><ul><li>If HCO3 is normal, then not compensating. </li></ul></ul>
    27. 28. Fluid & Electrolyte Balance
    28. 29. Where’s the water?
    29. 30. Water content varies with age & tissue type <ul><li>Infants – 73% </li></ul><ul><li>Adult male – 60% </li></ul><ul><li>Adult female – 50% </li></ul><ul><li>Elderly – 45% </li></ul><ul><li>Fat has the lowest water content (~20%). </li></ul><ul><li>Bone is close behind (~22 – 25%). </li></ul><ul><li>Skeletal muscle is highest at ~65%. </li></ul>
    30. 31. Functions of Body Fluid <ul><li>Major component of blood plasma </li></ul><ul><li>Solvent for nutrients and waste products </li></ul><ul><li>Necessary for hydrolysis of nutrients </li></ul><ul><li>Essential for metabolism </li></ul><ul><li>Lubricant in joints and GI tract </li></ul><ul><li>Cools the body through perspiration </li></ul><ul><li>Provides some mineral elements </li></ul>
    31. 32. Composition of Body Fluids <ul><li>Body fluids contain Electrolytes </li></ul><ul><ul><li>Anions – negative charge </li></ul></ul><ul><ul><ul><li>Cl, HCO3, SO4 </li></ul></ul></ul><ul><ul><li>Cations – positive charge </li></ul></ul><ul><ul><ul><li>Na, K, Ca </li></ul></ul></ul><ul><li>Electrolytes are measured in mEq </li></ul><ul><li>Minerals are ingested as compounds and are constituents of all body tissues and fluids </li></ul><ul><li>Minerals act as catalysts </li></ul>
    32. 33. Electrolytes in Body Fluids <ul><li>Normal Values </li></ul><ul><ul><li>Sodium (Na+) 35 – 145 mEq/L </li></ul></ul><ul><ul><li>Potassium (K+) 3.5 – 5.0 mEq/L </li></ul></ul><ul><ul><li>Ionized Calcium (Ca++) 4.5 – 5.5 mg/dL </li></ul></ul><ul><ul><li>Calcium (Ca++) 8.5 – 10.5 mg/dL </li></ul></ul><ul><ul><li>Bicarbonate (HCO 3 ) 24 – 30 mEq/L </li></ul></ul><ul><ul><li>Chloride (Cl -- ) 95 – 105 mEq/L </li></ul></ul><ul><ul><li>Magnesium (Mg++) 1.5 – 2.5 mEq/L </li></ul></ul><ul><ul><li>Phosphate (PO 4 --- ) 2.8 – 4.5 mg/dL </li></ul></ul>
    33. 34. Body Fluids <ul><li>Intracellular fluid (ICF) </li></ul><ul><ul><li>found within the cells of the body </li></ul></ul><ul><ul><li>constitutes 2/3 of total body fluid in adults </li></ul></ul><ul><ul><li>major cation is potassium </li></ul></ul><ul><li>Extracellular fluid (ECF) </li></ul><ul><ul><li>found outside the cells </li></ul></ul><ul><ul><li>accounts of 1/3 of total body fluid </li></ul></ul><ul><ul><li>major cation is sodium </li></ul></ul>
    34. 35. Terms <ul><li>Osmosis: movement of water across cell membranes from less concentrated to more concentrated </li></ul><ul><li>Solutes: substances dissolved in a liquid </li></ul><ul><li>Osmolality: the concentration within a fluid </li></ul><ul><li>Diffusion: movement of molecules in liquids from an area of higher concentration to lower concentration </li></ul><ul><li>Filtration: fluid and solutes move together across a membrane from area of higher pressure to one of lower pressure </li></ul><ul><li>Active Transport: substance moves across cell membranes from less concentrated solution to more concentrated - requires a carrier </li></ul>
    35. 36. Routes of Fluid Loss <ul><li>Urine </li></ul><ul><li>Insensible fluid loss </li></ul><ul><li>Feces </li></ul>
    36. 37. Electrolytes <ul><li>Sodium </li></ul><ul><li>Potassium </li></ul><ul><li>Chloride </li></ul><ul><li>Phosphate </li></ul><ul><li>Magnesium </li></ul><ul><li>Calcium </li></ul><ul><li>Bicarbonate </li></ul><ul><li>Electrolytes are important for: </li></ul><ul><li>Maintaining fluid balance </li></ul><ul><li>Contributing to acid-base regulation </li></ul><ul><li>Facilitating enzyme reactions </li></ul><ul><li>Transmitting neuromuscular reactions </li></ul>
    37. 38. Electrolyte concentrations are calculated in milliequivalents mEq/L = ion concentration (mg/L) x number of charges on one ion atomic weight Na + concentration in the body is 3300 mg/L Na + carries a single positive charge. Its atomic weight is approximately 23. Therefore, in a human the normal value for Na + is: 3300 mg/L = 143 mEq/L 23 Note: One mEq of a univalent is equal to one mOsm whereas one mEq of a bivalent ion is equal to ½ mOsm. However, the reactivity of 1 mEq is equal to 1 mEq.
    38. 39. Relative electrolyte concentrations: Plasma, Interstitial Fluid & ICF
    39. 40. Sources of intake & output
    40. 41. Regulation of water balance <ul><li>It is not so much water that is regulated, but solutes. </li></ul><ul><li>osmolality is maintained at between 285 – 300 mOsm. </li></ul><ul><li>An increase above 300 mOsm triggers: </li></ul><ul><ul><li>Thirst </li></ul></ul><ul><ul><li>Antidiuretic Hormone release </li></ul></ul>
    41. 42. The Thirst Mechanism An increase of 2 – 3% in plasma osmolality triggers the thirst center of the hypothalamus. Secondarily, a 10 – 15% drop in blood volume also triggers thirst. This is a significantly weaker stimulus.
    42. 43. Dehydration <ul><li>Chronic dehydration leads to oliguria . </li></ul><ul><li>Severe dehydration can result in hypovolemic shock . </li></ul><ul><li>Causes include: </li></ul><ul><li>Hemorrhage </li></ul><ul><li>Burns </li></ul><ul><li>Vomiting </li></ul><ul><li>Diarrhea </li></ul><ul><li>Sweating </li></ul><ul><li>Diuresis, which can be caused by diabetes insipidus, diabetes mellitus and hypertension (pressure diuresis). </li></ul>
    43. 44. Hypotonic hydration <ul><li>A severe drop in osmolality </li></ul><ul><li>Caused by: </li></ul><ul><ul><li>Excessive water intake </li></ul></ul><ul><ul><li>Renal dysfunction </li></ul></ul><ul><li>Major consequence is hyponatremia. </li></ul><ul><li>Hyponatremia results in: </li></ul><ul><ul><li>Cerebral edema (brain swelling) </li></ul></ul><ul><ul><li>Sluggish neural activity </li></ul></ul><ul><ul><li>Convulsions, muscle spasms, deranged behavior. </li></ul></ul><ul><li>Treated with I.V. hypertonic mannitol or something similar. </li></ul>
    44. 45. A rather lame illustration You do remember how osmosis works, don’t you?
    45. 46. Sodium regulation
    46. 47. Blood pressure, sodium, and water
    47. 48. Atrial Naturetic Peptide: The heart’s own compensatory mechanism.
    48. 49. Reabsorption of bicarbonate
    49. 50. Generation of new bicarbonate from phosphate
    50. 51. Generation of bicarbonate from glutamine deamination
    51. 52. Movement of Body Fluids <ul><li>Osmosis = movement across a semi-permeable membrane from area of lesser concentration to are of higher concentration; high solute concentration has a high osmotic pressure and draws water toward itself </li></ul><ul><ul><li>Osmotic pressure = drawing power of water (Osmolality) </li></ul></ul><ul><ul><li>Osmolarity = concentration of solution </li></ul></ul>
    52. 53. Movement of Body Fluids <ul><li>Colloid or Oncotic pressure = keeps fluid in the intravascular compartment by pulling water from the interstitial space back into the capillaries </li></ul>
    53. 55. Solutions <ul><li>Isotonic Solution </li></ul><ul><ul><li>The same concentration as blood plasma; expand fluid volume without causing fluid shift </li></ul></ul><ul><li>Hypotonic Solution </li></ul><ul><ul><li>Lower concentration than blood plasma; moves fluid into the cells causing them to enlarge </li></ul></ul><ul><li>Hypertonic solution </li></ul><ul><ul><li>Higher concentration than blood plasma; pulls fluid from cells causing them to shrink </li></ul></ul>
    54. 56. Movement of Body Fluids <ul><li>Diffusion = Molecules move from higher concentration to lower </li></ul><ul><ul><ul><li>Concentration gradient </li></ul></ul></ul><ul><li>Filtration = water and diffusible substances move together across a membrane; moving from higher pressure to lower pressure </li></ul><ul><li>Edema results from accumulation of excess fluid in the interstitial space </li></ul><ul><li>Hydrostatic pressure causes the movement of fluids from an area of higher pressure to area of lower pressure </li></ul>
    55. 59. Active Transport <ul><li>Requires metabolic activity and uses energy to move substances across cell membranes </li></ul><ul><ul><li>Enables larger substances to move into cells </li></ul></ul><ul><ul><li>Molecules can also move to an area of higher concentration (Uphill) </li></ul></ul><ul><ul><li>Sodium-Potassium Pump </li></ul></ul><ul><ul><ul><li>Potassium pumped in – higher concentration in ICF </li></ul></ul></ul><ul><ul><ul><li>Sodium pumped out – higher concentration in ECF </li></ul></ul></ul>
    56. 61. Regulation of Body Fluids <ul><li>Homeostasis is maintained through </li></ul><ul><ul><li>Fluid intake </li></ul></ul><ul><ul><li>Hormonal regulation </li></ul></ul><ul><ul><li>Fluid output regulation </li></ul></ul>
    57. 62. Fluid Intake <ul><li>Thirst control center located in the hypothalamus </li></ul><ul><ul><li>Osmoreceptors monitor the serum osmotic pressure </li></ul></ul><ul><ul><li>When osmolarity increases (blood becomes more concentrated), the hypothalamus is stimulated resulting in thirst sensation </li></ul></ul><ul><ul><ul><li>Salt increases serum osmolarity </li></ul></ul></ul><ul><li>Hypovolemia occurs when excess fluid is lost </li></ul>
    58. 63. Fluid Intake <ul><li>Average adult intake </li></ul><ul><ul><li>2200 – 2700 mL per day </li></ul></ul><ul><ul><ul><li>Oral intake accounts for 1100 – 1400 mL per day </li></ul></ul></ul><ul><ul><ul><li>Solid foods about 800 – 1000 mL per day </li></ul></ul></ul><ul><ul><ul><li>Oxidative metabolism – 300 mL per day </li></ul></ul></ul><ul><li>Those unable to respond to the thirst mechanism are at risk for dehydration </li></ul><ul><ul><li>Infants, patients with neuro or psych problems, and older adults </li></ul></ul>
    59. 64. Hormonal Regulation <ul><li>ADH (Antidiuretic hormone) </li></ul><ul><ul><li>Stored in the posterior pituitary and released in response to serum osmolarity </li></ul></ul><ul><ul><li>Pain, stress, circulating blood volume effect the release of ADH </li></ul></ul><ul><ul><ul><li>Increase in ADH = Decrease in urine output = Body saves water </li></ul></ul></ul><ul><ul><li>Makes renal tubules and ducts more permeable to water </li></ul></ul>
    60. 65. Hormonal Regulation <ul><li>Renin-angiotensin-aldosterone mechanism </li></ul><ul><ul><li>Changes in renal perfusion initiates this mechanism </li></ul></ul><ul><ul><li>Renin responds to decrease in renal perfusion secondary to decrease in extracellular volume </li></ul></ul><ul><ul><li>Renin acts to produce angiotensin I which converts to angiotensin II which causes vasoconstriction, increasing renal perfusion </li></ul></ul><ul><ul><li>Angiotensin II stimulates the release of aldosterone when sodium concentration is low </li></ul></ul>
    61. 66. Hormonal Regulation <ul><li>Aldosterone </li></ul><ul><ul><li>Released in response to increased plasma potassium levels or as part of the renin-angiotensin-aldosterone mechanism to counteract hypovolemia </li></ul></ul><ul><ul><li>Acts on the distal portion of the renal tubules to increase the reabsorption of sodium and the secretion and excretion of potassium and hydrogen </li></ul></ul><ul><ul><li>Water is retained because sodium is retained </li></ul></ul><ul><ul><li>Volume regulator resulting in restoration of blood volume </li></ul></ul>
    62. 67. Hormonal Regulation <ul><li>Atrial Natriuretic Peptide (ANP) </li></ul><ul><ul><li>ANP is a hormone secreted from atrial cells of the heart in response to atrial stretching and an increase in circulating blood volume </li></ul></ul><ul><ul><li>ANP acts like a diuretic that causes sodium loss and inhibits the thirst mechanism </li></ul></ul><ul><ul><li>Monitored in CHF </li></ul></ul>
    63. 68. Fluid Output Regulation <ul><li>Organs of water loss </li></ul><ul><ul><li>Kidneys </li></ul></ul><ul><ul><li>Lungs </li></ul></ul><ul><ul><li>Skin </li></ul></ul><ul><ul><li>GI tract </li></ul></ul>
    64. 69. Fluid Output Regulation <ul><li>Kidneys are major regulatory organ of fluid balance </li></ul><ul><ul><li>Receive about 180 liters of plasma to filter daily </li></ul></ul><ul><ul><li>1200 – 1500 mL of urine produced daily </li></ul></ul><ul><ul><li>Urine volume changes related to variation in the amount and type of fluid ingested </li></ul></ul><ul><li>Skin </li></ul><ul><ul><li>Insensible Water Loss </li></ul></ul><ul><ul><ul><li>Continuous and occurs through the skin and lungs </li></ul></ul></ul><ul><ul><ul><li>Can significantly increase with fever or burns </li></ul></ul></ul><ul><ul><li>Sensible Water Loss occurs through excess perspiration </li></ul></ul><ul><ul><ul><li>Can be sensible or insensible via diffusion or perspiration </li></ul></ul></ul><ul><ul><li>500 – 600 mL of insensible and sensible fluid lost through skin each day </li></ul></ul>
    65. 70. Fluid Output Regulation <ul><li>Lungs </li></ul><ul><ul><li>Expire approx 500 mL of water daily </li></ul></ul><ul><ul><li>Insensible water loss increases in response to changes in resp rate and depth and oxygen administration </li></ul></ul><ul><li>GI Tract </li></ul><ul><ul><li>3 – 6 liters of isotonic fluid moves into the GI tract and then returns to the ECF </li></ul></ul><ul><ul><li>200 mL of fluid is lost in the feces each day </li></ul></ul><ul><ul><ul><li>Diarrhea can increase this loss significantly </li></ul></ul></ul>
    66. 71. Regulation of Electrolytes <ul><li>Major Cations in body fluids </li></ul><ul><ul><li>Sodium (Na+) </li></ul></ul><ul><ul><li>Potassium (K+) </li></ul></ul><ul><ul><li>Calcium (Ca++) </li></ul></ul><ul><ul><li>Magnesium (Mg++) </li></ul></ul>
    67. 72. Sodium Regulation <ul><li>Most abundant cation in the extracellular fluid </li></ul><ul><ul><li>Major contributor to maintaining water balance </li></ul></ul><ul><ul><ul><li>Nerve transmission </li></ul></ul></ul><ul><ul><ul><li>Regulation of acid-base balance </li></ul></ul></ul><ul><ul><ul><li>Contributes to cellular chemical reactions </li></ul></ul></ul><ul><li>Sodium is taken in via food and balance is maintained through aldosterone </li></ul>
    68. 73. Potassium Regulation <ul><li>Major electrolyte and principle cation in the extracellular fluid </li></ul><ul><ul><li>Regulates metabolic activities </li></ul></ul><ul><ul><li>Required for glycogen deposits in the liver and skeletal muscle </li></ul></ul><ul><ul><li>Required for transmission of nerve impulses, normal cardiac conduction and normal smooth and skeletal muscle contraction </li></ul></ul><ul><ul><li>Regulated by dietary intake and renal excretion </li></ul></ul>
    69. 74. Calcium Regulation <ul><li>Stored in the bone, plasma and body cells </li></ul><ul><ul><li>99% of calcium is in the bones and teeth </li></ul></ul><ul><ul><li>1% is in ECF </li></ul></ul><ul><ul><li>50% of calcium in the ECF is bound to protein (albumin) </li></ul></ul><ul><ul><li>40% is free ionized calcium </li></ul></ul><ul><ul><li>Is necessary for </li></ul></ul><ul><ul><ul><li>Bone and teeth formation </li></ul></ul></ul><ul><ul><ul><li>Blood clotting </li></ul></ul></ul><ul><ul><ul><li>Hormone secretion </li></ul></ul></ul><ul><ul><ul><li>Cell membrane integrity </li></ul></ul></ul><ul><ul><ul><li>Cardiac conduction </li></ul></ul></ul><ul><ul><ul><li>Transmission of nerve impulses </li></ul></ul></ul><ul><ul><ul><li>Muscle contraction </li></ul></ul></ul>
    70. 75. Magnesium Regulation <ul><li>Essential for enzyme activities </li></ul><ul><li>Neurochemical activities </li></ul><ul><li>Cardiac and skeletal muscle excitability </li></ul><ul><li>Regulation </li></ul><ul><ul><li>Dietary </li></ul></ul><ul><ul><li>Renal mechanisms </li></ul></ul><ul><ul><li>Parathyroid hormone action </li></ul></ul><ul><li>50 – 60% of magnesium contained in bones </li></ul><ul><ul><li>1% in ECF </li></ul></ul><ul><ul><li>Minimal amount in cell </li></ul></ul>
    71. 76. Anions <ul><li>Chloride (Cl - ) </li></ul><ul><ul><li>Major anion in ECF </li></ul></ul><ul><ul><li>Follows sodium </li></ul></ul><ul><li>Bicarbonate (HCO 3 - ) </li></ul><ul><ul><li>Is the major chemical base buffer </li></ul></ul><ul><ul><li>Is found in ECF and ICF </li></ul></ul><ul><ul><li>Regulated by kidneys </li></ul></ul>
    72. 77. Anions <ul><li>Phosphate (PO 4 --- ) </li></ul><ul><ul><li>Buffer ion found in ICF </li></ul></ul><ul><ul><li>Assists in acid-base regulation </li></ul></ul><ul><ul><li>Helps to develop and maintain bones and teeth </li></ul></ul><ul><ul><li>Calcium and phosphate are inversely proportional </li></ul></ul><ul><ul><li>Promotes normal neuromuscular action and participates in carbohydrate metabolism </li></ul></ul><ul><ul><li>Absorbed through GI tract </li></ul></ul><ul><ul><li>Regulated by diet, renal excretion, intestinal absorption and PTH </li></ul></ul>
    73. 78. Causes of Electrolyte Imbalances <ul><li>Excessive sweating </li></ul><ul><li>Fluid loss leading to dehydration </li></ul><ul><li>Excessive vomiting </li></ul><ul><li>Diuretics like Lasix (K+ depletion) </li></ul><ul><li>Massive blood loss </li></ul><ul><li>Dehydration may go unnoticed in hot, dry climates </li></ul><ul><li>Renal failure </li></ul>
    74. 79. <ul><li>Sodium </li></ul><ul><li>Most abundant in extracellular space </li></ul><ul><li>Moves among three fluid compartments </li></ul><ul><li>Found in most body secretions </li></ul>
    75. 80. Hyponatremia – Low Sodium <ul><li>Seizures </li></ul><ul><li>Personality changes </li></ul><ul><li>Nausea/vomiting </li></ul><ul><li>Tachycardia </li></ul><ul><li>Convulsion </li></ul><ul><li>Normal Na (135-145) </li></ul>
    76. 81. Hypernatremia <ul><li>Excessive Na in ECF </li></ul><ul><li>Loss of water </li></ul><ul><ul><li>Diarrhea </li></ul></ul><ul><ul><li>Insensible water loss </li></ul></ul><ul><ul><li>Water deprivation </li></ul></ul><ul><li>Gain of Sodium </li></ul><ul><ul><li>Diabetes insipidus </li></ul></ul><ul><ul><li>Heat stroke </li></ul></ul>
    77. 82. Hypokalemia – Low Potassium <ul><li>Severe leg cramps </li></ul><ul><li>Flaccid muscles </li></ul><ul><li>Fatigue </li></ul><ul><li>Irregular pulse </li></ul><ul><li>Chest discomfort </li></ul><ul><li>EKG changes </li></ul><ul><ul><li>T wave flattens </li></ul></ul><ul><li>Normal Potassium-3.5-5 </li></ul>
    78. 83. Hyperkalemia <ul><li>CNS </li></ul><ul><ul><li>Nausea and vomiting </li></ul></ul><ul><li>Peripheral Nervous System </li></ul><ul><ul><li>Tremors, twitching </li></ul></ul><ul><li>Heart </li></ul><ul><ul><li>Bradycardia, peaked T wave </li></ul></ul>
    79. 84. Hypocalcemia – Low Calcium <ul><li>Tingling of fingers </li></ul><ul><li>Tetany </li></ul><ul><li>Muscle cramps </li></ul><ul><li>Positive Trousseau’s </li></ul><ul><ul><li>Carpal spasm </li></ul></ul><ul><li>Positive Chvostek’s </li></ul><ul><ul><li>Contraction of facial muscle when facial nerve tapped </li></ul></ul>
    80. 85. Hypercalcemia <ul><li>Causes </li></ul><ul><ul><li>Prolonged immobility </li></ul></ul><ul><ul><li>Osteoporosis </li></ul></ul><ul><ul><li>Thiazide diuretics </li></ul></ul><ul><ul><li>Acidosis </li></ul></ul><ul><li>Signs/symptoms </li></ul><ul><ul><li>N/V, weakness </li></ul></ul><ul><ul><li>Hypoactive reflexes </li></ul></ul><ul><ul><li>Cardiac arrest </li></ul></ul>
    81. 86. Hypomagnesemia <ul><li>Causes </li></ul><ul><ul><li>Malnutrition </li></ul></ul><ul><ul><li>Alcoholism </li></ul></ul><ul><ul><li>Polyuria </li></ul></ul><ul><ul><li>Pre-ecclampsia </li></ul></ul><ul><li>Signs/symptoms </li></ul><ul><ul><li>Muscle tremor </li></ul></ul><ul><ul><li>Hyperactive deep reflexes </li></ul></ul><ul><ul><li>Chvostek’s/Trousseau’s </li></ul></ul><ul><ul><li>Difficulty breathing </li></ul></ul>
    82. 87. Hypermagnesemia <ul><li>Causes </li></ul><ul><ul><li>Renal failure </li></ul></ul><ul><ul><li>Excessive intake </li></ul></ul><ul><li>Signs/symptoms </li></ul><ul><ul><li>Low BP </li></ul></ul><ul><ul><li>Muscle weakness </li></ul></ul><ul><ul><li>Absent reflexes </li></ul></ul><ul><ul><li>Bradycardia </li></ul></ul>
    83. 88. Cheat Sheet <ul><li>Increase pH – alkalosis </li></ul><ul><li>Decrease pH – acidosis </li></ul><ul><li>Respiratory – CO2 </li></ul><ul><li>Metabolic (kidneys)– HCO3 </li></ul><ul><li>CO2 has an inverse relationship with pH </li></ul><ul><li>When pH goes down, CO2 goes up </li></ul><ul><li>HCO3 follows pH. If pH goes up so does HCO3 </li></ul><ul><li>CO2 increases, pH decreases – resp. acidosis </li></ul><ul><li>CO2 decreases, pH increases – resp. alkalosis </li></ul><ul><li>HCO3 increases, pH increases – metabolic alkalosis </li></ul><ul><li>HCO3 decreases, pH decreases – metabolic acidosis </li></ul>
    84. 89. Question <ul><li>An older client comes to the emergency department experiencing chest pain and shortness of breath. An arterial blood gas is ordered. Which of the following ABG results indicates respiratory acidosis? </li></ul><ul><ul><li>1. pH - 7.54, PaCO2 – 28, HCO3 – 22 </li></ul></ul><ul><ul><li>2. pH – 7.32, PaCO2 – 46, HCO3 – 24 </li></ul></ul><ul><ul><li>3. pH – 7.31, PaCO2 – 35, HCO3 – 20 </li></ul></ul><ul><ul><li>4. pH – 7.5, PaCO2 – 37, HCO3 - 28 </li></ul></ul>