Acid-Base Metabolism

  1. What is the term for the system that can resist change in pH; composed of a weak acid or a weak base and its corresponding salt?
  2. Name the 4 buffer systems of clinical importance exist in whole blood
    • Bicarbonate-carbonic acid buffer system
    • Protein buffer system
    • Phosphate buffer system
    • Hemoglobin buffer system
  3. What is the most important intracellular buffer?
    Hemoglobin buffer system
  4. What is the most important buffer system in plasma?
    Bicarbonate-carbonic acid buffer system
  5. What is the term for the process to supply cells with oxygen for metabolic processes and remove the carbon dioxide produced during metabolism?
  6. What is the term for in a mixture of gases, partial pressure is the amount of pressure contributed by each gas to the total pressure exerted by the mixture?
    Partial pressure
  7. What occurs when arterial blood pH <7.35?
  8. What occurs when arterial blood pH >7.45?
  9. What is increased in blood PCO2?
  10. What is decreased in blood PCO2?
  11. What is measured in the blood as mm Hg?
    Partial pressure of carbon dioxide (PCO2)
  12. What includes undissociated carbonic acid (H2CO3) and carbon dioxide dissolved in blood (represented by PCO2)?
    Concentration of dissolved carbon dioxide (cdCO2)
  13. What includes bicarbonate (primary component), carbamino-bound CO2, carbonic acid, and dissolved carbon dioxide?
    Concentration of total carbon dioxide (ctCO2)
  14. The pH of plasma is a function of what 2 independent variables and how are they regulated?
    • Partial pressure of carbon dioxide (PCO2) - regulated by the lungs or respiratory mechanism
    • Concentrtion of bicarbonate (HCO3-) - regulated by the kidneys
  15. What is the calculation of cdCO2?
    • cdCO2 = PCO2 x a (solubility coefficient of CO2)
    • Where a = 0.03 mmol/L per mm Hg
  16. What is the average normal ratio of cHCO3- to cdCO2?
  17. What is the reference range for arterial pH?
  18. What is the reference range of ctCO2?
    22-26 mmol/L
  19. What is the reference range of PCO2?
    35-45 mm Hg
  20. How are acid-base disorders classified?
    • Metabolic acidosis
    • Metabolic alkalosis
    • Respiratory acidosis
    • Respiratory alkalosis
  21. What disorder primarily involve bicarbonate concentration?
    Metabolic acid-base disorders
  22. What disorder primarily involves dissolved carbon dioxide concentration?
    Respiratory acid-base disorders
  23. What disorder has the following lab findings?
    ctCO2 decreased
    PCO2 normal
    pH decrease
    Bicarbonate concentration decreases
    Decrease in the 20:1 ratio between cHCO3- and cdCO2
    Caused by: Primary bicarbonate deficit, Organic acid production, Ingestion exceed the excretion rate, Diabetic ketoacidosis, Lactic acidosis, Poisonings such as salicylate, ethylene glycol, and methyl alcohol, Reduced acid excretion, Loss of bicarbonate
    Metabolic (nonrespiratory) acidosis
  24. What does a decrease in blood pH trigger and why?
    Decreased pH triggers hyperventilation that lowers PCO2 and results in an increase in pH
  25. What disorder has the following lab findings?
    ctCO2 increased
    PCO2 normal
    pH increased
    Bicarbonate concentration increases 
    Increase in the 20:1 ratio between cHCO3- and cdCO2
    Caused by: Primary bicarbonate excess, Ingestion of excess base, Decreased elimination of base, Loss of acidic fluids, IV administration of bicarbonate, Renal barbonate retention, Prolongs diuretic use, Loss of hydrochloric acid, Intestinal obstruction, Gastric suction, Cushing syndrome, Mineralocorticoid
    Metabolic (nonrespiratory) alkalosis
  26. What does an increase in blood pH trigger?
    • Increase in pH slows breathing, thus increasing the amount of CO2 retained by the lungs
    • Increases H2CO3
    • Lower pH
  27. What disorder has the following lab findings?
    ctCO2 normal
    PCO2 increased
    pH decreased
    Caused by: Primary cdCO2 excess expressed as increase in PCO2 (hypercapnia), Chronic obstructive pulmonary disease, Ingestion of narcotics and barbiturates, Severe infections of the CNS
    Respiratory acidosis
  28. How is blood pH raised in Respiratory acidosis?
    Kidneys increase sodium-hydrogen exchange, ammonia formation, and bicarbonate retention
  29. What disorder has the following lab results?
    ctCO2 normal
    PCO2 decreased
    pH increased
    Caused by: Primary cdCO2 deficit expressed as decrease in PCO2 (hypocapnia), Hypoxia, Anxiety, Nervousness, Excessive crying, Pulmonary embolism, Pneumonia, Congestive heart failure, Salicylate overdose
    Repiratory alkalosis
  30. How is oxygen transported?
    Bound to hemoglobin present in RBCs and in a physically dissolved state
  31. What 3 factors control oxygen transport?
    • PCO2
    • Free diffusion of oxygen across the alveolar membrane
    • Affinity of hemoglobin for oxygen
  32. How is the release of oxygen to the tissues facilitated?
    Facilitated by an increase in H+ concentration and PCO2 levels at the tissue level
  33. What are the causes of increase values of PO2 levels?
    Supplemental oxygen
  34. What are the causes of hypoxemia?
    • Decreased pulmonary diffusion
    • Decreased alveolar spaces
    • Poor ventilation/perfusion due to obstructed airways
Card Set
Acid-Base Metabolism
Major Buffer Systems, Definitions, Acid Base Balance and Disorders, and Oxygen Metabolism