Acid Base Balance for EMS

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Acid Base Balance for EMS presentation - appropriate for all levels of EMS personnel; includes interactive components for audience and small group participation and learning; questions? call Porter, Littleton and Parker EMS in Colorado at 303-765-6367 (303-765-6EMS)

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Acid Base Balance for EMS

  1. 1. Acid-Base Balance for EMS Anne Clouatre, MHS, EMT-P EMS Regional Program Director Centura Health Porter, Littleton and Parker Adventist Hospitals Emergency Medical Services 303-765-6367
  2. 2. Objectives <ul><li>Describe pH, acid, base, and buffer. </li></ul><ul><li>Compare and contrast the three buffer systems. </li></ul><ul><li>Arrange the normal blood gas values. </li></ul><ul><li>Differentiate blood gas values for respiratory </li></ul><ul><li>and metabolic acidosis and alkalosis. </li></ul><ul><li>Evaluate common conditions that may cause acidosis and/or alkalosis. </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  3. 3. pH <ul><li>What does it mean? </li></ul><ul><li>pH stands for the p otential for H ydrogen </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  4. 4. pH Scale <ul><li>The pH scale represents the concentration of hydrogen ions (H + ) and hydroxyl ions (OH - ) in fluids. </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  5. 5. pH Scale <ul><li>The scale ranges from 0-14 </li></ul><ul><ul><li>What is the neutral point on this scale? </li></ul></ul><ul><li>What number is maximum acidity? </li></ul><ul><li>What number is maximum alkalinity? </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  6. 6. pH Scale <ul><li>Each unit on the scale represents a logarithm: pH = 1 </li></ul><ul><ul><ul><ul><ul><li> log[H+] </li></ul></ul></ul></ul></ul><ul><ul><li>Therefore, pH = -log[H+] </li></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  7. 7. Definition of logarithm <ul><li>A logarithm is a mathematical concept that eases the calculation of large numbers. The log of a number is the exponent of the power to which a given base must be raised to equal that number. </li></ul><ul><ul><li>T he log of 100 is 2 (100=10 2 ) </li></ul></ul><ul><ul><li>T he log of 1,000 is 3 (1,000 = 10 3 ) </li></ul></ul><ul><ul><ul><ul><ul><li>Brady Paramedic Emergency Care, p. 284 </li></ul></ul></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  8. 8. pH Scale <ul><li>What is the pH of a 0.0020 M solution of HCl? </li></ul><ul><ul><li>Answer: </li></ul></ul><ul><ul><ul><li>pH = -log[H+] </li></ul></ul></ul><ul><ul><ul><li>pH = -log (2.0 x 10 -3 ) </li></ul></ul></ul><ul><ul><ul><ul><li>= -(log 2.0 + log 10 -3 ) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>= -[0.30 + (-3)] </li></ul></ul></ul></ul><ul><ul><ul><ul><li>=-(-2.70) </li></ul></ul></ul></ul><ul><ul><ul><li>Therefore, pH = 2.70 </li></ul></ul></ul><ul><ul><ul><ul><ul><li>General Chemistry, 4e; pp. 551, A-6 </li></ul></ul></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  9. 9. pH Scale <ul><li>Because of the logarithmic nature of the pH scale, there is a 10-fold difference between each unit on the scale. </li></ul><ul><ul><li>Therefore, multiply by 10 for every 1 point of increase or decrease on the scale. </li></ul></ul><ul><ul><ul><li>A pH of 5.0 is 10x as acidic as a pH of 6.0 </li></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  10. 10. pH Scale <ul><li>A pH of 4.0 is how many times as acid as a pH of 6.0? </li></ul><ul><ul><li>Answer: 100 times (10x10 = 100) </li></ul></ul><ul><li>A pH of 11.0 is how many times as alkaline as a pH of 7.0? </li></ul><ul><ul><li>Answer: 10,000 times (10x10x10x10 = 10,000) </li></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  11. 11. Acids <ul><li>What is an acid? </li></ul><ul><ul><li>It is neither LSD nor crud on your battery terminals! </li></ul></ul><ul><ul><li>It is a substance that increases H + ions in water. Increasing acidity is expressed as a number LESS than 7. </li></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  12. 12. What is a base? <ul><li>a. A substance, which in water, is equal to increasing the concentration of OH - ions </li></ul><ul><li>b. What you slide into after a good hit in baseball </li></ul><ul><li>c. A substance that decreases the concentration of H + ions </li></ul><ul><li>d. Somewhere you can call for medical consultation </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  13. 13. Human Beings <ul><li>Extraordinarily sensitive to pH changes </li></ul><ul><li>Most material within cells = 6.8 </li></ul><ul><li>Blood plasma = 7.35-7.45 </li></ul><ul><li>Fluids around cells = 7.2-7.3 </li></ul><ul><li>What are the maximum acid and alkaline pH values that are still conducive to (barely) maintaining life?: </li></ul><ul><ul><li>6.9 on the acidotic side </li></ul></ul><ul><ul><li>7.8 on the alkalotic side </li></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  14. 14. Let’s draw a pH scale! <ul><li>Need: paper and a writing utensil </li></ul><ul><li>Activity: </li></ul><ul><ul><li>1. Draw the pH scale with a straight, horizontal line. Label it with numbers from 0 to 14 </li></ul></ul><ul><ul><ul><li>0 on the far left and 14 on the far right </li></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  15. 15. Add these to your pH scale (There is one for each number.) <ul><li>Oven cleaner </li></ul><ul><li>Tomatoes </li></ul><ul><li>Stomach acid </li></ul><ul><li>Baking soda </li></ul><ul><li>Black coffee </li></ul><ul><li>Urine </li></ul><ul><li>Lemon juice </li></ul><ul><li>Beer </li></ul><ul><li>Sea water </li></ul><ul><li>Household ammonia </li></ul><ul><li>Bicarbonate of soda </li></ul><ul><li>Great Salt Lake </li></ul><ul><li>Hydrochloric acid </li></ul><ul><li>Distilled water </li></ul><ul><li>Sodium hydroxide </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  16. 16. Answers…How many do you have correct? <ul><li>pH 0-hydrochloric acid </li></ul><ul><li>pH 1-stomach acid </li></ul><ul><li>pH 2-lemon juice </li></ul><ul><li>pH 3-ice cold beer (also, cola and vinegar) </li></ul><ul><li>pH 4-tomatoes </li></ul><ul><li>pH 5-hot, black coffee </li></ul><ul><li>pH 6-urine (saliva is 6.5) </li></ul><ul><li>pH 7-distilled water (blood is 7.4) </li></ul><ul><li>pH 8-sea water </li></ul><ul><li>pH 9-baking soda </li></ul><ul><li>pH 10-Great Salt Lake </li></ul><ul><li>pH 11-household ammonia </li></ul><ul><li>pH 12-bicarbonate of soda </li></ul><ul><li>pH 13-oven cleaner </li></ul><ul><li>pH 14-sodium hydroxide (NaOH) Paramedic Field Care, p. 116 </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  17. 17. Buffers <ul><li>“ A substance, especially a salt of the blood, tending to preserve original hydrogen-ion concentration of its solution, upon adding an acid or base. </li></ul><ul><li>… principal blood buffers include carbonic acid, carbonates, bicarbonates, monobasic and dibasic phosphates, and proteins. Hemoglobin is an important protein buffer.” </li></ul><ul><ul><ul><ul><ul><li>Taber’s Cyclopedic Medical Dictionary, 18th ed, p. 275 </li></ul></ul></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  18. 18. Buffers and pH Balance <ul><li>pH balance is carefully regulated by three bodily systems: </li></ul><ul><ul><li>blood chemicals </li></ul></ul><ul><ul><li>lungs </li></ul></ul><ul><ul><li>kidneys </li></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  19. 19. Bicarbonate-Carbonic Acid Buffer <ul><li>This is the first and quickest way of maintaining acid-base balance. </li></ul><ul><li>This buffer is dependent upon the lung and kidney buffers: </li></ul><ul><ul><li>Respiratory Renal </li></ul></ul><ul><ul><li>CO 2 + H 2 O H 2 CO 3 H + + HCO 3 - </li></ul></ul><ul><ul><li>Carbonic Acid </li></ul></ul><ul><ul><li>Blood Buffer </li></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  20. 20. Bicarbonate-Carbonic Acid Buffer <ul><li>Reaction occurs mostly in erythrocytes </li></ul><ul><ul><li>About 80% of extracellular fluid buffering occurs by way of this buffer system </li></ul></ul><ul><li>There are 20 parts of HCO 3 - (bicarbonate) </li></ul><ul><li>to every 1 part of H 2 CO 3 (carbonic acid). </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  21. 21. What do each of these represent? <ul><li>CO 2 </li></ul><ul><li>H 2 O </li></ul><ul><li>H 2 CO 3 </li></ul><ul><li>H + </li></ul><ul><li>HCO 3 - </li></ul><ul><li>O 2 </li></ul><ul><li>Bonus: CO </li></ul><ul><li>carbon dioxide </li></ul><ul><li>water </li></ul><ul><li>carbonic acid </li></ul><ul><li>hydrogen </li></ul><ul><li>bicarbonate </li></ul><ul><li>oxygen </li></ul><ul><li>carbon monoxide </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  22. 22. Respiratory Buffer System <ul><li>Second fastest; reacts in 1-3 minutes </li></ul><ul><li>“ Triggered by the action of chemoreceptors in the respiratory centers of the brain stem that detect pH in cerebrospinal fluid” Paramedic Field Care, p. 115 </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  23. 23. Respiratory Buffer System <ul><li>Example: </li></ul><ul><ul><li>Patient with diabetic ketoacidosis (DKA) </li></ul></ul><ul><ul><li>What type of respirations will this person have and why? </li></ul></ul><ul><ul><ul><li>Rapid and deep respirations…They indicate that the respiratory system is blowing off CO 2 and H 2 O to rid the body of excess acid by producing a RESPIRATORY ALKALOSIS. </li></ul></ul></ul><ul><ul><ul><ul><li>This is how the body tries to compensate for the METABOLIC ACIDOSIS brought on by the DKA. </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Paramedic Field Care, p. 115-116 </li></ul></ul></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  24. 24. Renal (Kidneys) Buffer System <ul><li>Slowest; takes hours to days but provides long-term acid-base balance maintenance </li></ul><ul><li>Kicks in when blood buffers and respiratory buffers are slacking off! </li></ul><ul><li>Kidneys regulate pH by excreting excess H + or HCO 3 - ions </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  25. 25. Renal (Kidneys) Buffer System <ul><li>What will the kidneys eliminate if the pH of the extracellular fluid is decreasing? </li></ul><ul><ul><ul><li>H + ions </li></ul></ul></ul><ul><li>What will the kidneys eliminate if the pH of the extracellular fluid is increasing? </li></ul><ul><ul><ul><li>HCO 3 - ions </li></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  26. 26. Normal Arterial Blood Gas Values <ul><li>pH </li></ul><ul><li>PaO 2 </li></ul><ul><li>PaCO 2 </li></ul><ul><li>HCO 3 </li></ul><ul><li>7.35 - 7.45 </li></ul><ul><li>90%-100% </li></ul><ul><li>35 - 45 </li></ul><ul><li>22 - 26 mEq/l </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  27. 27. Normal Arterial Blood Gas Values <ul><li>Normal PaO 2 depends </li></ul><ul><li>on altitude…therefore, the “full range” </li></ul><ul><li>of normal PaO 2 is 70%-100%. Paramedic Field Care, p. 117 </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  28. 28. Arrange the blood gas values <ul><li>1. Normal range for pH </li></ul><ul><li>2. Normal range for PaO 2 </li></ul><ul><li>3. Acidotic range for pH </li></ul><ul><li>4. Normal range for PaCO 2 </li></ul><ul><li>5. Alkalotic range for pH </li></ul><ul><li>6. Normal range for HCO 3 - </li></ul><ul><li>7. Acidotic range for PaCO 2 </li></ul><ul><li>8. Alkalotic range for PaCO 2 </li></ul><ul><li>22 - 26 mEq/l </li></ul><ul><li>7.35 - 7.45 </li></ul><ul><li>Over 45 </li></ul><ul><li>70%-100% </li></ul><ul><li>35 - 45 </li></ul><ul><li>Below 35 </li></ul><ul><li>Over 7.45 </li></ul><ul><li>Below 7.35 </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  29. 29. Respiratory Derangements <ul><li>Respiratory </li></ul><ul><li>Acidosis_________ </li></ul><ul><ul><li>Caused by retention of CO 2 </li></ul></ul><ul><ul><li>pH is decreased </li></ul></ul><ul><ul><li>CO 2 level is increased </li></ul></ul><ul><li>Respiratory Alkalosis________ </li></ul><ul><ul><li>Caused by excessive elimination of CO2 </li></ul></ul><ul><ul><li>pH is increased </li></ul></ul><ul><ul><li>CO2 level is decreased </li></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  30. 30. Respiratory Derangements <ul><li>Respiratory </li></ul><ul><li>Acidosis_________ </li></ul><ul><li>What are some causes for the retained CO 2 ? </li></ul><ul><li>What is the treatment? </li></ul><ul><li>Respiratory Alkalosis________ </li></ul><ul><li>What are some causes for the loss of CO 2 ? </li></ul><ul><li>What is the treatment? </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  31. 31. Metabolic Derangements <ul><li>Metabolic </li></ul><ul><li>Acidosis_________ </li></ul><ul><ul><li>Caused by production of metabolic acids </li></ul></ul><ul><ul><li>pH is decreased </li></ul></ul><ul><ul><li>CO 2 level is normal </li></ul></ul><ul><li>Metabolic Alkalosis________ </li></ul><ul><ul><li>Caused by excessive diuretics, prolonged emesis, or too much bicarb administration </li></ul></ul><ul><ul><li>pH is increased </li></ul></ul><ul><ul><li>CO 2 level is normal </li></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  32. 32. Metabolic Derangements <ul><li>Metabolic </li></ul><ul><li>Acidosis_________ </li></ul><ul><li>What are some causes for the production of metabolic acids? </li></ul><ul><li>What is the treatment? </li></ul><ul><li>Metabolic Alkalosis________ </li></ul><ul><li>What are some causes for the alkalosis? </li></ul><ul><li>What is the treatment? </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  33. 33. Respiratory Acidosis <ul><li>What is it? </li></ul><ul><li>What are the lab values? </li></ul><ul><li>Numerous causes: </li></ul><ul><ul><li>Central - narcotic, sedative, alcohol overdose; CNS lesions </li></ul></ul><ul><ul><li>Neuromuscular - hypokalemia, botulism </li></ul></ul><ul><ul><li>Thoracic-pulmonary - pneumonia, smoke inhalation, pneumothorax </li></ul></ul><ul><ul><li>Airway obstruction - foreign body </li></ul></ul><ul><ul><ul><ul><ul><li>Adapted from Haddad’s Poisoning and Drug Overdose , p. 141 </li></ul></ul></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  34. 34. Respiratory Alkalosis <ul><li>What is it? </li></ul><ul><li>What are the lab values? </li></ul><ul><li>Numerous causes: </li></ul><ul><ul><li>General - anxiety, pain, fever, encephalitis, meningitis sedative </li></ul></ul><ul><ul><li>Peripheral - hypotension, hypoxemia, CHF, pulmonary embolism </li></ul></ul><ul><ul><li>Miscellaneous - mechanical ventilation, sepsis, cirrhosis </li></ul></ul><ul><ul><ul><ul><ul><li>Adapted from Haddad’s Poisoning and Drug Overdose , p. 141 </li></ul></ul></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  35. 35. Metabolic Acidosis <ul><li>What is it? </li></ul><ul><li>What are the lab values? </li></ul><ul><li>Numerous causes: </li></ul><ul><ul><li>Renal failure, diabetic ketoacidosis, ibuprofen overdose, antifreeze ingestion (ethylene glycol intoxication) </li></ul></ul><ul><ul><li>Diarrhea, parenteral alimentation, hydrochloric acid ingestion </li></ul></ul><ul><ul><ul><ul><ul><li>Adapted from Haddad’s Poisoning and Drug Overdose , p. 122, 133 </li></ul></ul></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  36. 36. Metabolic Alkalosis <ul><li>What is it? </li></ul><ul><li>What are the lab values? </li></ul><ul><li>Numerous causes: </li></ul><ul><ul><li>Sodium chloride-responsive - diuretics, cystic fibrosis </li></ul></ul><ul><ul><li>Sodium chloride-resistant - licorice ingestion, chewing tobacco </li></ul></ul><ul><ul><li>Miscellaneous - bicarbonate administration, penicillin, milk-alkali syndrome </li></ul></ul><ul><ul><ul><ul><ul><li>Adapted from Haddad’s Poisoning and Drug Overdose , p. 138 </li></ul></ul></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  37. 37. What’s the matter? <ul><li>pH: 7.20, PCO 2 : 30, HCO 3 - : 16 </li></ul><ul><li>Respiratory alkalosis, metabolic acidosis </li></ul><ul><li>POTENTIAL CAUSE? Shock </li></ul><ul><li>pH: 7.60, PCO 2 : 27, HCO 3 - : 23 </li></ul><ul><li>Respiratory alkalosis </li></ul><ul><li> POTENTIAL CAUSE? hyperventilation </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  38. 38. What’s the matter? <ul><li>pH: 7.12, PCO 2 : 68, HCO 3 - : 29 </li></ul><ul><li>Respiratory acidosis, metabolic alkalosis </li></ul><ul><li>POTENTIAL CAUSE? Long-term COPD’er </li></ul><ul><li>pH: 7.2, PCO 2 : 60, HCO 3 - : 14 </li></ul><ul><li>Respiratory acidosis, metabolic acidosis </li></ul><ul><li> POTENTIAL CAUSE? Cardiac arrest </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  39. 39. Clinical Features <ul><li>RESPIRATORY </li></ul><ul><li>ACIDOSIS </li></ul><ul><li>Altered LOC </li></ul><ul><li>Tachycardia </li></ul><ul><li>Cardiac dysrhythmias </li></ul><ul><li>Diaphoresis </li></ul><ul><li>Visual disturbances </li></ul><ul><li>Headache </li></ul><ul><li>Abnormal breathing </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  40. 40. Clinical Features <ul><li>RESPIRATORY </li></ul><ul><li>ALKALOSIS </li></ul><ul><li>Circumoral paresthesia </li></ul><ul><li>Digital paresthesia </li></ul><ul><li>Carpopedal spasm </li></ul><ul><li>Altered LOC </li></ul><ul><li>Seizures </li></ul><ul><li>Tetany </li></ul><ul><li>(All are related to neuromuscular irritability.) </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  41. 41. Clinical Features <ul><li>METABOLIC </li></ul><ul><li>ACIDOSIS </li></ul><ul><li>Tachycardia </li></ul><ul><li>Pulmonary edema </li></ul><ul><li>Cardiac dysrhythmias </li></ul><ul><li>Decreased cardiac output </li></ul><ul><li>Tachypnea </li></ul><ul><li>Deep breathing </li></ul><ul><li>Confusion - coma </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  42. 42. Clinical Features <ul><li>METABOLIC </li></ul><ul><li>ALKALOSIS </li></ul><ul><li>Neuromuscular irritability </li></ul><ul><li>Seizures </li></ul><ul><li>Tetany </li></ul><ul><li>Delirium </li></ul><ul><li>Hyperreflexia </li></ul><ul><li>Cardiac dysrhythmias </li></ul><ul><li>Headache </li></ul><ul><li>Abnormal breathing </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  43. 43. Super Mind Tank Scenarios <ul><li>1. Break into groups of 2-3 people </li></ul><ul><li>2. Design a scenario to share with the class. Create it so that you can ask the audience at least 2 questions about your patient. </li></ul><ul><li>3. Include the following in your scenario: </li></ul><ul><ul><ul><li>Patient chief complaint </li></ul></ul></ul><ul><ul><ul><li>Physical exam findings </li></ul></ul></ul><ul><ul><ul><li>Vital signs </li></ul></ul></ul><ul><ul><ul><li>Patient pH, PaCO 2 , and HCO 3 - </li></ul></ul></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  44. 44. Objectives Assessment <ul><li>Can you describe pH, acid, base, and buffer? </li></ul><ul><li>Are you able to compare and contrast the three buffer systems? </li></ul><ul><li>Can you arrange the normal blood gas values? </li></ul><ul><li>Are you able to differentiate blood gas values for respiratory and metabolic acidosis and alkalosis? </li></ul><ul><li>Can you evaluate common conditions that </li></ul><ul><li>may cause acidosis and/or alkalosis? </li></ul>Porter, Littleton and Parker EMS 303-765-6EMS
  45. 45. THANK YOU Feel free to contact me or the rest of our team if you have any questions or comments: Anne - 303.765.6367 Porter, Littleton and Parker EMS 303-765-6EMS

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