Acid Base Balance and Fluid Balance

1. Acid Base Balance and Fluid Balance Dr. Kathleen Ethridge Northeast Texas Community College

3. Body Fluids Intracellular fluid (ICF) found within the cells of the body constitutes 2/3 of total body fluid in adults major cation is potassium Extracellular fluid (ECF) found outside the cells accounts of 1/3 of total body fluid major cation is sodium

4. Terms Osmosis movement of water across cell membranes from less concentrated to more concentrated Solutes substances dissolved in a liquid Osmolality the concentration within a fluid

5. More Terms Diffusion movement of molecules in liquids from an area of higher concentration to lower concentration Filtration fluid and solutes move together across a membrane from area of higher pressure to one of lower pressure Active Transport substance moves across cell membranes from less concentrated solution to more concentrated - requires a carrier

6. Routes of Fluid Loss Urine Insensible fluid loss Feces

7. Electrolytes Sodium Potassium Chloride Phosphate Magnesium Calcium Bicarbonate

8. Acid-Base Balance Acid-Base balance is: the regulation of HYDROGEN ions.

9. pH The acidity or alkalinity of a solution is measured as pH. The more acidic a solution, the lower the pH. The more alkaline a solution , the higher the pH. Water has a pH of 7 and is neutral. The pH of arterial blood is normally between 7.35 and 7.45

10. Hydrogen ions The more Hydrogen ions, the more acidic the solution and the LOWER the pH The lower Hydrogen concentration, the more alkaline the solution and the HIGHER the pH

11. pH Know what is normal.

12. Buffer Systems Regulate pH by binding or releasing Hydrogen Most important buffer system: Bicarbonate-Carbonic Acid Buffer System (Blood Buffer systems act instantaneously and thus constitute the body’s first line of defense against acid-base imbalance)

13. Acid Base Balance

14. Respiratory ComponentRenal Component

15. Respiratory Regulation Lungs help regulated acid-base balance by eliminating or retaining carbon dioxide pH may be regulated by altering the rate and depth of respirations changes in pH are rapid, occurring within minutes normal CO2 level 35 to 45 mm Hg

16. Renal Regulation Kidneys the long-term regulator of acid-base balance slower to respond may take hours or days to correct pH kidneys maintain balance by excreting or conserving bicarbonate and hydrogen ions normal bicarbonate level 22 to 26 mEq/L.

17. Factors Affecting Balance Age especially infants and the elderly Gender and Body Size amount of fat Environmental Temperature Lifestyle stress

18. Acid-Base Imbalances Respiratory Acidosis Respiratory Alkalosis Metabolic Acidosis Metabolic Alkalosis

19. See Chart

20. Respiratory Acidosis Mechanism Hypoventilation or Excess CO2 Production Etiology COPD Neuromuscular Disease Respiratory Center Depression Late ARDS Inadequate mechanical ventilation Sepsis or Burns Excess carbohydrate intake

21. Respiratory Acidosis (cont) Symptoms Dyspnea, Disorientation or coma Dysrhythmias pH < 7.35, PaCO2 > 45mm Hg Hyperkalemia or Hypoxemia Treatment Treat underlying cause Support ventilation Correct electrolyte imbalance IV Sodium Bicarb

22. Respiratory Alkalosis Risk Factors and etiology Hyperventilation due to extreme anxiety, stress, or pain elevated body temperature overventilation with ventilator hypoxia salicylate overdose hypoxemia (emphysema or pneumonia) CNS trauma or tumor

23. Respiratory Alkalosis (cont) Symptoms Tachypnea or Hyperpnea Complaints of SOB, chest pain Light-headedness, syncope, coma, seizures Numbness and tingling of extremities Difficult concentrating, tremors, blurred vision Weakness, paresthesias, tetany Lab findings pH above 7.45 CO2 less than 35

24. Respiratory Alkalosis (cont) Treatment Monitor VS and ABGs Treat underlying disease Assist client to breathe more slowly Help client breathe in a paper bag or apply rebreather mask Sedation

25. Metabolic Acidosis Risk Factors/Etiology Conditions that increase acids in the blood Renal Failure DKA Starvation Lactic acidosis Prolonged diarrhea Toxins (antifreeze or aspirin) Carbonic anhydrase inhibitors - Diamox

26. Metabolic Acidosis (cont) Symptoms Kussmaul’s respiration Lethargy, confusion, headache, weakness Nausea and Vomiting Lab: pH below 7.35 Bicarb less than 22 Treatment treat underlying cause monitor ABG, I&O, VS, LOC Sodium Bicarb?

27. Metabolic Alkalosis Risk Factors/Etiology Acid loss due to vomiting gastric suction Loss of potassium due to steroids diuresis Antacids (overuse of)

28. Metabolic Alkalosis (cont) Symptoms Hypoventilation (compensatory) Dysrhythmias, dizziness Paresthesia, numbness, tingling of extremities Hypertonic muscles, tetany Lab: pH above 7.45, Bicarb above 26 CO2 normal or increased w/comp Hypokalmia, Hypocalcemia Treatment I&O, VS, LOC give potassium treat underlying cause

30. Pneumonic Respiratory Opposite Metabolic Equal

31. Interpreting ABGs 1. Look at the pH is the primary problem acidosis (low) or alkalosis (high) 2. Check the CO2 (respiratory indicator) is it less than 35 (alkalosis) or more than 45 (acidosis) 3. Check the HCO3 (metabolic indicator) is it less than 22 (acidosis) or more than 26 (alkalosis) 4. Which is primary disorder (Resp. or Metabolic)? If the pH is low (acidosis), then look to see if CO2 or HCO3 is acidosis (which ever is acidosis will be primary). If the pH is high (alkalosis), then look to see if CO2 or HCO3 is alkalosis (which ever is alkalosis is the primary). The one that matches the pH (acidosis or alkalosis), is the primary disorder.

32. Compensation The Respiratory system and Renal systems compensate for each other attempt to return the pH to normal ABG’s show that compensation is present when the pH returns to normal or near normal If the nonprimary system is in the normal range (CO2 35 to 45) (HCO3 22-26), then that system is not compensating for the primary. For example: In respiratory acidosis (pH<7.35, CO2>45), if the HCO3 is >26, then the kidneys are compensating by retaining bicarbonate. If HCO3 is normal, then not compensating.