Fluid and Electrolytes: Balance and Disturbance Dr. Abdul-Monim Batiha

1. Fluid and Electrolytes: Balance and DisturbanceDr. Abdul-Monim Batiha

2. Fluid and Electrolyte Balance • Necessary for life, homeostasis • Nursing role: help prevent, treat fluid, electrolyte disturbances

3. Fluid • Approximately 60% of typical adult is fluid • Varies with age, body size, gender • Intracellular fluid • Extracellular fluid • Intravascular: the fluid within the blood vessels e.g. plazma • Interstitial: fluid surrounds the cell (e.g. lymph • Transcellular: cerebrospinal, pericardial, synovial, intraocular, pleural, sweat and digestive secretion • “Third spacing”: loss of ECF into space that does not contribute to equilibrium

6. Electrolytes • Active chemicals that carry positive (cations), negative (anions) electrical charges • Major cations: sodium, potassium, calcium, magnesium, hydrogen ions • Major anions: chloride, bicarbonate, phosphate, sulfate, and proteinate ions • Electrolyte concentrations differ in fluid compartments

7. Regulation of Fluid • Movement of fluid through capillary walls depends on • Hydrostatic pressure: exerted on walls of blood vessels • Osmotic pressure: exerted by protein in plasma • Direction of fluid movement depends on differences of hydrostatic, osmotic pressure

8. Regulation of Fluid • Osmosis: area of low solute concentration to area of high solute concentration • Diffusion: solutes move from area of higher concentration to one of lower concentration • Filtration: movement of water, solutes occurs from area of high hydrostatic pressure to area of low hydrostatic pressure • Active transport: physiologic pump that moves fluid from area of lower concentration of one of higher concentration

11. Active Transport • Physiologic pump that moves fluid from area of lower concentration to one of higher concentration • Movement against concentration gradient • Sodium-potassium pump: maintains higher concentration of extracellular sodium, intracellular potassium • Requires adenosine (ATP) for energy

13. Question • Tell whether the following statement is true or false: • Osmosis is the movement of a substance from an area of higher concentration to one of lower concentration.

14. Answer • False. • Rationale: Diffusion is the movement of a substance from an area of higher concentration to one of lower concentration. The concentration of dissolved substances draws fluid in that direction. Osmosis is the movement of fluid, through a semipermeable membrane, from an area of low solute concentration to an area of high solute concentration until the solutions are of equal concentration.

15. Routes of Gains and Losses • Gain • Dietary intake of fluid, food or enteral feedingIngested fluid (60%) and solid food (30%) • Metabolic water or water of oxidation (10%) • Parenteral fluids

16. Routes of Gains and Losses (cont’d) • Loss • Kidney: urine output • Skin loss: sensible, insensible losses • Lungs • GI tract • Other • Urine (60%) and feces (4%) • Insensible losses (28%), sweat (8%)

17. Chapter 26: Fluid, Electrolyte, and Acid-Base Balance Water Intake and Output Figure 26.4

18. Question • What is the average daily urinary output in an adult? • 0.5 L • 1.0 L • 1.5 L • 2.5 L

19. Answer • C. 1.5 L • Rationale: Vital to the regulation of fluid and electrolyte balance, the kidneys normal filter 170 L of plasma every day in the adult, while excreting only 1.5 L of urine.

20. Regulation of Water Intake • The hypothalamic thirst center is stimulated: • By a decline in plasma volume of 10%–15% • By increases in plasma osmolality of 1–2% • Via baroreceptor input, angiotensin II, and other stimuli

21. Thirst is reduced as soon as we begin to drink water • Feedback signals that inhibit the thirst centers include: • Moistening of the mucosa of the mouth and throat • Activation of stomach and intestinal stretch receptors

22. Regulation of Water Output • Obligatory water losses include: • Insensible water losses from lungs and skin • Water that accompanies undigested food residues in feces • Obligatory water loss reflects the fact that: • Kidneys excrete 900-1200 mOsm of solutes to maintain blood homeostasis • Urine solutes must be flushed out of the body in water

23. Influence and Regulation of ADH • Water reabsorption in collecting ducts is proportional to ADH release • Low ADH levels produce dilute urine and reduced volume of body fluids • High ADH levels produce concentrated urine • Hypothalamic osmoreceptors trigger or inhibit ADH release • Factors that specifically trigger ADH release include prolonged fever; excessive sweating, vomiting, or diarrhea; severe blood loss; and traumatic burns

24. Mechanisms and Consequences of ADH Release Figure 26.6

26. Fluid Volume Imbalances • Fluid volume deficit (FVD): hypovolemia • Fluid volume excess (FVE): hypervolemia

27. Fluid Volume Deficit • Loss of extracellular fluid exceeds intake ratio of water • Electrolytes lost in same proportion as they exist in normal body fluids • Dehydration: loss of water along with increased serum sodium level • May occur in combination with other imbalances

28. Fluid Volume Deficit (cont’d) • Dehydration • Causes: fluid loss from vomiting, diarrhea, GI suctioning, sweating, decreased intake, inability to gain access to fluid • Risk factors: diabetes insipidus, adrenal insufficiency, osmotic diuresis, hemorrhage, coma,

29. Fluid Volume Deficit (cont’d) • Manifestations: rapid weight loss, decreased skin turgor, oliguria, concentrated urine, postural hypotension, rapid weak pulse, increased temperature, cool clammy skin due to vasoconstriction, lethargy, thirst, nausea, muscle weakness, cramps • Laboratory data: elevated BUN in relation to serum creatinine, increased hematocrit • Serum electrolyte changes may occur

30. Fluid Volume Deficit (cont’d) • Medical management: provide fluids to meet body needs • Oral fluids • IV solutions (isotonic electrolytes solution; e.g. ringer lactate solution or 0.9 sodium chloride)

31. Fluid Volume Deficit - Nursing Management • I&O, VS • Monitor for symptoms: skin and tongue turgor, mucosa, UO, mental status • Measures to minimize fluid loss • Oral care • Administration of oral fluids • Administration of parenteral fluids

32. Question • What is a major indicator of extracellular FVD? • Full and bounding pulse • Drop in postural blood pressure • Elevated temperature • Pitting edema of lower extremities

33. Answer • B. Drop in postural blood pressure • Rationale: FVD signs and symptoms include acute weight loss; decreased skin turgor; oliguria; concentrated urine; orthostatic hypotension due to volume depletion; a weak, rapid heart rate; flattened neck veins; increased temperature; thirst; decreased or delayed capillary refill; decreased central venous pressure; cool, clammy, pale skin related to peripheral vasoconstriction; anorexia; nausea; lassitude; muscle weakness; and cramps. Clinical manifestations of FVE result from expansion of the ECF and include edema, distended neck veins, and crackles (abnormal lung sounds).

34. Fluid Volume Excess • Due to fluid overload or diminished homeostatic mechanisms • Risk factors: heart failure, renal failure, cirrhosis of liver • Contributing factors: excessive dietary sodium or sodium-containing IV solutions • Manifestations: edema, distended neck veins, abnormal lung sounds (crackles), tachycardia, increased BP, pulse pressure and CVP, increased weight, increased UO, shortness of breath and wheezing • Medical management: directed at cause, restriction of fluids and sodium, administration of diuretics

36. Disorders of Water Balance: Edema • Atypical accumulation of fluid in the interstitial space, leading to tissue swelling • Caused by anything that increases flow of fluids out of the bloodstream or hinders their return • Factors that accelerate fluid loss include: • Increased blood pressure, capillary permeability • Incompetent venous valves, localized blood vessel blockage • Congestive heart failure, hypertension, high blood volume

37. Edema • Hindered fluid return usually reflects an imbalance in colloid osmotic pressures • Hypoproteinemia – low levels of plasma proteins • Forces fluids out of capillary beds at the arterial ends • Fluids fail to return at the venous ends • Results from protein malnutrition, liver disease, or glomerulonephritis

38. Chapter 26: Fluid, Electrolyte, and Acid-Base Balance Edema • Blocked (or surgically removed) lymph vessels: • Cause leaked proteins to accumulate in interstitial fluid • Exert increasing colloid osmotic pressure, which draws fluid from the blood • Interstitial fluid accumulation results in low blood pressure and severely impaired circulation

39. Fluid Volume Excess - Nursing Management • I&O and daily weights; assess lung sounds, edema, other symptoms; monitor responses to medications- diuretics • Promote adherence to fluid restrictions, patient teaching related to sodium and fluid restrictions • Monitor, avoid sources of excessive sodium, including medications • Promote rest • Semi-Fowler’s position for orthopnea • Skin care, positioning/turning

40. Electrolyte Imbalances • Sodium: hyponatremia, hypernatremia • Potassium: hypokalemia, hyperkalemia • Calcium: hypocalcemia, hypercalcemia • Magnesium: hypomagnesemia, hypermagnesemia • Phosphorus: hypophosphatemia, hyperphosphatemia • Chloride: hypochloremia, hyperchloremia

41. Hyponatremia • Serum sodium less than 135 mEq/L • Causes: adrenal insufficiency, water intoxication, SIADH (Syndrome of inappropriate ADH secretion) or losses by vomiting, diarrhea, sweating, diuretics • Manifestations: poor skin turgor, dry mucosa, headache, decreased salivation, decreased BP, nausea, abdominal cramping, neurologic changes • Medical management: water restriction, sodium replacement • Nursing management: assessment and prevention, dietary sodium and fluid intake, identify and monitor at-risk patients, effects of medications (diuretics, lithium)

42. Hypernatremia • Serum sodium greater than 145mEq/L • Causes: excess water loss, excess sodium administration, diabetes insipidus, heat stroke, hypertonic IV solutions • Manifestations: thirst; elevated temperature; dry, swollen tongue; sticky mucosa; neurologic symptoms; restlessness; weakness • Note: thirst may be impaired in elderly or the ill • Medical management: hypotonic electrolyte solution or D5W • Nursing management: assessment and prevention, assess for OTC (Over the counter drugs) sources of sodium, offer and encourage fluids to meet patient needs, provide sufficient water with tube feedings

44. Hypokalemia • Below-normal serum potassium (<3.5 mEq/L), may occur with normal potassium levels with alkalosis due to shift of serum potassium into cells • Causes: GI losses, medications, alterations of acid-base balance, hyperaldosterism, poor dietary intake • Manifestations: fatigue, anorexia, nausea, vomiting, dysrhythmias, muscle weakness and cramps, paresthesias, glucose intolerance, decreased muscle strength and DTRs • Medical management: increased dietary potassium, potassium replacement, IV for severe deficit • Nursing management: assessment, severe hypokalemia is life-threatening, monitor ECG and ABGs, dietary potassium, nursing care related to IV potassium administration

45. Hyperkalemia • Serum potassium greater than 5.0 mEq/L • Causes: usually treatment related, impaired renal function, hypoaldosteronism, tissue trauma, acidosis • Manifestations: cardiac changes and dysrhythmias, muscle weakness with potential respiratory impairment, paresthesias, anxiety, GI manifestations • Medical management: monitor ECG, limitation of dietary potassium, cation-exchange resin (Kayexalate), IV sodium bicarbonate , IV calcium gluconate, regular insulin and hypertonic dextrose IV, -2 agonists, dialysis

46. Hyperkalemia (cont’d) • Nursing management: assessment of serum potassium levels, mix IVs containing K+ well, monitor medication affects, dietary potassium restriction/dietary teaching for patients at risk • Hemolysis of blood specimen or drawing of blood above IV site may result in false laboratory result • Salt substitutes, medications may contain potassium • Potassium-sparing diuretics may cause elevation of potassium • Should not be used in patients with renal dysfunction

47. Question • Tell whether the following statement is true or false: • The ECG change that is specific to hyperkalemia is a peaked T wave.

48. Answer • True. • Rationale: The ECG changes that are specific to hyperkalemia are peaked T wave; wide, flat P wave; and wide QRS complex. The ECG changes that are specific to hypokalemia are flatted T wave and the appearance of a U wave.

49. Hypocalcemia • Serum level less than 8.5 mg/dL, must be considered in conjunction with serum albumin level • Causes: hypoparathyroidism, malabsorption, pancreatitis, alkalosis, massive transfusion of citrated blood, renal failure, medications, other • Manifestations: tetany, circumoral numbness, paresthesias, hyperactive DTRs, Trousseau’s sign, Chovstek's sign, seizures, respiratory symptoms of dyspnea and laryngospasm, abnormal clotting, anxiety

50. Hypocalcemia (cont’d) • Medical management: IV of calcium gluconate, calcium and vitamin D supplements; diet • Nursing management: assessment, severe hypocalcemia is life-threatening, weight-bearing exercises to decrease bone calcium loss, patient teaching related to diet and medications, and nursing care related to IV calcium administration