Fluid & Electrolytes Acid Base Imbalances Chapter 17

1. Megan McClintock Winter 2012 Fluid & ElectrolytesAcid Base ImbalancesChapter 17

2. Maintained by the intake and output of water and electrolytes and regulation by the renal and pulmonary systems Acid-base balance is necessary for many physiologic processes (respiration, metabolism, function of the CNS) Many disease and treatments affect this balance Homeostasis

3. More important to life than any other nutrient 60% of an adult’s body weight, more in a child, less in the elderly Found in foods (but not in alcohol) Daily need is about 2000 mL 1 liter of water weighs 1 kg Water

4. Measures the kidney’s ability to concentrate or dilute urine • 1.002 – 1.028 • High is dehydrated • Low is overhydrated (or unable to concentrate) • Kidney failure often causes a fixed specific gravity Urine specific gravity

5. Cations (positively charged) • K+, Na+, Ca+, Mg+ • Transmit nerve impulses to muscles and contract skeletal and smooth muscles • Anions (negatively charged) • Attached to cations • Cl-, HCO3-, PO4-, SO4- • Are always kept in balance Electrolytes

6. Intracellular (2/3) – K+, PO4- • Extracellular (1/3) – Na+, Cl- • Interstitial (lymph) • Intravascular (blood plasma) • Transcellular (cerebrospinal, pleural, peritoneal, synovial fluids) Distribution of body fluids & Electrolytes

7. Regulation of Fluid & Electrolyte Movement

8. Indicates the water balance of the body • Serum osmolality (275 - 295) • High is water deficit • Low is water excess • Urine osmolality (100-1300) • High is concentrated • Low is dilute Osmolality

9. Fluid Spacing • First spacing • Normal • Second spacing • Edema • Third spacing • Ascites • Burn edema

10. Regulation of Water Balance • Hypothalmic Regulation • Thirst is stimulated • ADH (vasopressin) release is stimulated • Pituitary Regulation • ADH (vasopressin) is released • Adrenal Cortical Regulation • Glucocorticoids & mineralocorticoids are released • Renal Regulation • Adjust urine volume and electrolyte excretion • Normal is 1.5 Liters of urine/day

11. Cardiac Regulation • ANP & BNP will stop the action of the adrenal cortex and the kidney • GI Regulation • Intake and output are reabsorbed here • Diarrhea and vomiting can lead to significant losses • Insensible Water Loss • 600-900 mL/day from the lungs and skin • Increases with fever, exercise Regulation of water balance (cont.)

12. Gerontologic considerations • Structural changes in the kidney and decreased renal blood flow • Decreased GFR • Decreased creatinine clearance • Loss of ability to concentrate urine and thus conserve water • Decrease in renin and aldosterone • Increase in ADH and ANP • Loss of subcutaneous tissue • Decrease in thirst mechanism • Musculoskeletal changes • Mental status changes • Incontinence

13. Fluid Volume Deficit • What causes it? • What can you do?

14. Fluid Volume Excess • What causes it? • What can you do?

15. Strict I/O • Intake – oral, IV, tube feedings, retained irrigants • Output – urine, excess sweating, wound/tube drainage, vomitus, diarrhea • Urine specific gravity • Assessment of CV, Resp, Neuro, Skin status • Daily weight under standardized conditions • Don’t “catch up” IV fluids • No water with NG suction, use isotonic saline • Keep fluids accessible and within reach • Give warm or cold fluids (not room temperature) Nursing interventions

16. Serum Electrolytes • Sodium (Na) 135 - 145 • Primarily responsible for maintaining osmotic pressure (intracellular and extracellular fluids) • Increased with fluid deficit • Decreased withfluid excess • Potassium (K) 3.5 – 5.0 • Major component of cardiac function • Increased with poor kidney function • Decreased with excessive urination, diarrhea or vomiting • Chloride (Cl) 96 – 106 • Works with Na to maintain osmotic pressure • Increased with poor kidney function • Decreased with excessive vomiting or diarrhea • Calcium (Ca) 8.6 – 10.2 • Transmission of nerve impulses, heart and muscle contractions, blood clotting, formation of teeth and bone • Phosphate (PO4) 2.4 – 4.4 • Function of muscle, RBCs, and the nervous system

17. The Magic fours ElectrolyteRangeMagic 4 Potassium 3.5 - 5.0 4 Chloride 96 - 106 104 Sodium 135 - 145 140 pH 7.35 - 7.45 7.4 CO2 35 - 45 40 HCO3 22 - 26 24 Hematocrit normal is 3 times the hemoglobin

18. Major cation of ECF Primary determinant of osmolality GI tract absorbs sodium from food Regulated by kidneys, ADH, aldosterone Sodium level reflects the ratio of sodium to water Imbalances are typically associated with fluid volume problems Sodium (135 - 145)

19. Hypernatremia (high sodium) • What causes it? What can you do?

20. What causes it? Hyponatremia (low sodium) • What can you do?

21. Major cation of ICF Sodium-potassium pump requires magnesium Moves into cells during formation of new tissues and leaves the cell during tissue breakdown Diet is the source of potassium Kidneys are primary route of loss Potassium (3.5 - 5.0)

22. Hyperkalemia (high potassium) • What causes it? • What can you do?

23. Hypokalemia (low potassium) • What causes it? • What can you do?

24. Primary source is bones Regulated by parathyroid hormone, calcitonin, and vitamin D Affects transmission of nerve impulses, heart and muscle contractions, blood clotting, and forming of teeth and bone Calcium (8.6 – 10.2)

25. Hypercalcemia (high calcium) • What causes it? • What are the symptoms? • What can you do?

26. Hyp0calcemia (Low calcium)

27. Hyperphosphatemia • Cause - renal failure • S/S – calcium deposits in joints, skin, kidneys, eyes; hypocalcemia, tetany, neuromuscular irritability • Tx – decrease intake of dairy products, good hydration, fix hypocalcemia • Hypophosphatemia • Cause – malnutrition, malabsorption syndrome, alcohol withdrawal • S/S – CNS depression, confusion, muscle weakness, dysrhythmias • Tx – oral supplements (Neutra-Phos), lots of dairy products, IV phosphate (but this can cause sudden hypocalcemia) Phosphate Imbalances

28. Hypermagnesemia • Cause – increased intake (ie. MOM, Maalox) with chronic kidney disease • S/S – lethargy, n/v, loss of DTRs, can have respiratory and cardiac arrest • Tx – avoid magnesium-containing drugs, IV calcium, increased fluid intake, may need dialysis • Hypomagnesemia • Cause – prolonged fasting or starvation, chronic alcoholism, diuretics • S/S – confusion, hyperactive DTRs, tremors, seizures, cardiac dysrhythmias • Tx – oral supplements, increase green veggies, nuts, bananas, oranges, peanut butter, chocolate; IV or IM magnesium (if given too rapidly can cause cardiac or respiratory arrest) Magnesium Imbalances

29. Medications • Loop diuretics • Thiazide diuretics • Potassium sparing diuretics • Electrolytes • Kayexolate

30. Acid Base Balance

31. Regulation of Acid-Base Balance • Buffer system (immediate) • Primary regulator • Won’t work without good functioning respiratory and renal symptoms • Respiratory system (minutes, max in hours) • Excretes CO2 and water • Renal system (2-3 days to max respond) • Reabsorbs HCO3

32. Arterial Blood Gas • pH (7.35 – 7.45) • CO2 (35 – 45) • HCO3 (22 – 26) • Base excess (+2 to -2) • If high, metabolic alkalosis • If low, metabolic acidosis

33. Determining Acid–Base Balance • Is pH acid, base or normal? • Is CO2 acid, base or normal? • Is HCO3 acid, base or normal? • Which of the components match? • Is there compensation? Is non-matching reading abnormal? – partial compensation Is non-matching reading normal? – no compensation

36. Respiratory Alkalosis

37. Respiratory Alkalosis • Causes • Hyperventilation • Pulmonary disease • High altitudes • Signs/symptoms • Hyperventilation • Feels “light-headed” • Arrhythmias • Anxiety • Treatment • Breathe into paper bag • Rebreather mask • Anti-anxiety medicine • Relaxation techniques • Reduce stimulation • Treat pain/fever • Assess: • Resp rate/depth • HR & BP • Serum K levels • Hydration status • Check for digitalis toxicity

38. Respiratory acidosis

39. Respiratory Acidosis • Causes • CNS depression • Loss of lung surface • Neuromuscular disease • Immobility • Mechanical ventilation • Signs/symptoms • Dyspnea • Hypoxia • Drowsiness • Tachycardia • Seizures • Diaphoresis • Treatment • Turn, cough, deep breathe • Semi-Fowler’s position • Suction • Incentive spirometer • Seizure precautions • Decrease use of sedatives • Bronchodilators • May need ventilator • Assess: • Resp rate/depth • HR & BP • Patiency of airway

40. Metabolic alkalosis

41. Metabolic Alkalosis • Causes • NG suctioning • Prolonged vomiting • Diuretic use • Multiple blood transfusions • CPR (given bicarb) • Signs/symptoms • Dizziness • Dysrhythmias • Convulsions • Confusion • Muscle cramps (late sign) • Treatment • Identify and treat the cause! • IV fluids • Stop giving bicarbonate • Give antiemetics • Give Diamox • Assess: • Resp rate/depth • HR & BP • Serum K levels (usually low) • Hydration status (tend to be dehydrated) • Check for digitalis toxicity • Parasthesias

42. Metabolic acidosis

43. Metabolic acidosis • Causes • Diabetic ketoacidosis • Renal or liver failure • Severe diarrhea • Vomiting • Starvation • Signs/symptoms • Kussmaul respirations • Hypotension • Arrythmias • Warm to hot ,flushed skin • Confusion • Treatment • Identify and treat the cause! • Administer insulin (if due to ketoacidosis) • Give antiemetics • IV fluids • IV bicarbonate • Assess: • Renal function (BUN, creatinine) • Serum K levels (tends to go up but down once insulin given) • Hydration status

44. IV Fluids • Isotonic • NS • D5W • LR • Hypertonic • 3% NS • D51/2NS • D10W • Hypotonic • 1/2NS • Plasma Expanders

45. Centrally inserted catheters (CVCs) • Peripherally inserted central catheters (PICCs) • Implanted infusion ports Central Venous access devices

46. Inspect site for redness, edema, warmth, drainage, pain Dressing change/cleaning with sterile technique using chlorhexidine (back and forth scrub to generate friction) Maintain transparent dressing c/d/I Change injection caps using sterile technique Teach pt to turn head away from insertion site during cleaning and cap change Have patient Valsalva during cap change if unable to clamp Use push-pause method to flush (creates turbulence) Removal of non-tunneled CVCs and PICCs may be done by a trained nurse (have pt Valsalva as last of catheter is withdrawn, apply pressure immediately, inspect catheter tip) Nursing care of CVADs