Acids and Bases

• Acid base normal

  Between 7.35 and 7.45
• Cellular function is impaired if pH isn't in normal range, can be fatal
• Acids

  Substances that release hydrogen ions when dissolved in water, increase hydrogen concentration. Created through metabolism and made as end products
• Carbonic acids


  Removed by the lungs
• Metabolic acids


  Removed by the kidneys
• Bases


  Substances that bind to free hydrogen in a solution
• Ways the body maintains acid-base balance

  • Chemical
  • Respiratory
  • Kidneys
• Chemical buffers

  • First line of defence, acts immediately on an acidic and basic environment
• Protein buffers

  Manage minimal changes in pH including hemoglobin, albumin, globulins
• Chemical buffers


  Include bicarbonate (primary buffer in body) and phosphate (urinary)
• Chemical buffers help keep pH in normal range even if there is constant production of acid
• Hemoglobin system


  Maintain acid base through chloride shift which is due to the amount of oxygen in the system. One Cl to one O2. Regulated in the red blood cell
• Plasma protein system


  Functions along with the liver and varies the number of H ions in the structure of plasma
• Phosphate buffer system


  Minor urinary buffer that acts like bicarbonate and neutralizes excess hydrogen
• Bicarbonate system

  20:1 ratio determines the hydrogen ion concentration of body fluid. Carbonic acid concentration is controlled by the excretion of CO2 in the lungs, the rate and depth of respiration change in response to the changes in CO
• Bicarbonate system


  Controlled by the kidneys which can be excreted and retained. Retention happens with COPD. Too much bicarbonate leads to alkalosis
• Respiratory system acid/base balance

  • Second defense in the body which can excrete and retain CO2. Acidosis increases the body's respirations and vice versa. Takes only 30 seconds to kick in
• Carbonic acid


  Broken down into CO2 and water
• Hypercapnia

  PaCO2 is greater than 45mmHg and pH less than 7.35
• Hypercapnia Mechanisms of failure

  • Abnormalities of airways, CNS, chest wall
• Hypercapnia Effects

  Respiratory acidosis, altered electrolytes with potassium, intracranial pressure, somnolence, coma, and hypoxemia
• Hypoxemia


  Less PaO2 than 60 mmHg on 60% oxygen. Due to failure in gas exchange between alveoli and capillaries
• Kidney system


  • Third line of defense with a response rate of one to two days but is the strongest
• Kidneys

  Restore bicarbonate by excreting hydrogen ions and retaining bicarbonate ions
• Excess hydrogen ions


  Excreted in the urine in the form of phosphoric acid. Is more selective
• Potassium imbalance always occurs with a pH imbalance
• In acidosis


  Potassium leaves in exchange for the high concentration of the rushing in of hydrogen. Leads to hyperkalemia
• In alkalosis

  Potassium moves in due to the small amount of hydrogen present in the cell. Leads to hypokalemia
• Respiratory acidosis


  Retaining CO2 which decreases pH. It is due to hypoventilation
• Compensation of Respiratory acidosis

  Kidneys reabsorb bicarbonate into the bloodstream, increasing the excretion of H
• Treatment of Respiratory acidosis

  Fix what is causing the hypoventilation
• Respiratory alkalosis


  Too little CO2 in the body, caused by hyperventilation and hypoxemia
• Corrections of Respiratory acidosis

  Include hypoventilation and excreting bicarbonate in urine
• Metabolic acidosis


  Too much acid for too little bicarbonate. Due to acid excess which can be caused by acid excess (fever / exercise) or bicarbonate deficit (Kidney failure)
• Correction of Metabolic acidosis

  Reabsorb bicarbonate into blood and increase secretion of H in urine
• Respiratory compensation of Metabolic acidosis

  Results in deep and rapid breaths
• Metabolic alkalosis


  Too little acid or too much bicarbonate (ingest baking soda). Can be caused intaking antacids and prolonged vomiting. Once hypoxemia occurs, ventilation starts to work
• Compensation of metabolic alkalosis

  Hypoventilation and excreting bicarbonate
• Clinical manifestations of acidosis

  • Cardiovascular: ECG change, hypotension, thready pulses, decreased BP
  • CNS: depressed activity (lethargy, headache stupor)
  • Neuromuscular: hypoflexia, skeletal weakness, flaccid paralysis
  • Respiratory: Kussmaul respirations, variable respirations
  • Integumentary: warm flushed and dry skin. Gets paler as they get stronger acidosis
• Alkalosis manifestations

  • Cardiovascular: increase HR and low BP
  • GI: nausea and vomiting
  • Respiratory: hyperventilation and decreased respiratory effort
  • CNS: increased activity, anxiety
  • Neuromuscular: hyperreflexia, muscle cramping