1. Acid-Base Balance KNH 413

2. Acid-Base Balance Acids- rise in pH Donate or give up H+ ions Nonvolatile acids or fixed acids Inorganic acids that occur through metabolism of CHO, protein, lipid Average amount 50-100 mmol/day Proteins contribute the most Lungs cannot eliminate

3. Acid-Base Balance Bases Can accept or receive H+ ions Bicarbonate HCO 3 Kidneys provide primary regulation

5. Acid-Base Balance pH Acidosis Accumulation of acid or loss of base Acidemia pH less than 7.35 Alkalosis- rare Accumulation of base or loss of acid Alkalemia pH greater than 7.45

6. Regulation of Acid-Base Balance Chemical buffers- in the middle, maintain the acid base balance, bicarbonate Respiratory regulation- increase the rate and the depth of your breath  CO2 production/excretion is increased Kidney regulation- reabsorb more bicarbonate if in a acidic condition

8. Regulation of Acid-Base Balance Respiratory regulatory control Change in respiration rate Depth of breathing Release or retention of CO 2

9. Regulation of Acid-Base Balance Renal regulatory control Control of HCO 3 (bicarbonate) by the kidneys Increased or decreased based on need Formation of dibasic phosphate and sulfur in the urine Accepts H+

11. Regulation of Acid-Base Balance Electrolyte Balance- Work on TPN solution to make sure they are not in acidosis Hydrogen and bicarbonate both electrolytes Other electrolytes affected to maintain electroneutrality Potassium, chloride, sodium

14. Acid-Base Disorders 4 major types Respiratory acidosis- lower pH, higher plasma, bicarb, increased CO2 production  excretes more H from the kidneys to alter this Respiratory alkalosis- pH up, bicarb, plasma and CO2 down Metabolic acidosis- lower pH, decreased plasma, bicarb, CO2 Metabolic alkalosis- increased pH, plasma, bicarb, CO2, kidneys increase bicarbonate excretion

16. Acid-Base Disorders Respiratory acidosis Excess acid in blood secondary to carbon dioxide retention Hypercapnia- too much CO2 in the blood, breathing to compensate that (hyperventilate) Common causes d/t respiratory dysfunction – renal regulatory systems compensate

18. Acid-Base Disorders Respiratory acidosis Labs Decreased pH, elevated pCO 3 Slightly elevated bicarbonate Increase in serum Ca, K, Cl (lab values) Hypoxemia- decreased partial pressure in the blood, decreased flow of O2 in the blood Restlessness, apprehension, lethargy, muscle twitching, tremors, convulsions, coma

19. Acid-Base Disorders Respiratory acidosis Treatment Correct underlying condition bring up the bicarbonate Increase oxygenation Mechanical ventilation

20. Acid-Base Disorders Respiratory alkalosis (hyperventilation) CO2 eliminated faster than it can be replaced Relative excess amount of base d/t reduction of CO 2 Hyperventilation Common causes - see Table 9.6 Shift of acid from ICF to ECF Bicarbonate moved into cells in exchange for chloride – renal compensation if they are functioning properly

22. Acid-Base Disorders Respiratory alkalosis pH > 7.45 Plasma HCO 3 low in chronic, PaCO 3 low in acute Cardiac, CNS, respiratory symptoms Treating underlying cause as a medical team Correction of hypoxia

23. Acid-Base Disorders Metabolic Acidosis All types not caused by excessive CO 2 Common causes Diarrhea most common cause d/t excessive loss of bicarbonate – bicarbonate- carbonic acid buffer system is stimulated

24. © 2007 Thomson - Wadsworth

28. Acid-Base Disorders Metabolic Acidosis Kussmaul breathing- deep labored breathing Cardiac and neurological (as a result of being acido.) Treat underlying cause Raise pH to safe level – not too quickly

29. Acid-Base Disorders Metabolic Alkalosis- RARE, from overuse of base, medically induced Excess amount of base Fluid imbalance – with volume decrease Without fluid imbalance – without volume decrease Common causes Underlying event determines pathophysiology- what is going on to cause them to lose this acid??

32. Assessment of Acid- Base Disorders © 2007 Thomson - Wadsworth