Fundamentals of Fluid and Electrolyte Balance Parenteral Solutions

1. Fundamentals of Fluid and Electrolyte BalanceParenteral Solutions ADN136 Fall 09

2. Fluid Balance • Body fluid is body water in which electrolytes are dissolved • Bodywater makes up • 60% of Total Body weight in young men • 50-55% in women • 70-80% in infants

3. Fluid Balance

4. Fluid Balance (cont) • Homeostasis- Dependent on fluid and electrolyte intake physiologic factors, disease state factors, external environmental factors and pharmacologic intervention. • Intracellular fluid (ICF) water in the cells = 40% • Extractracellular fluid (ECF) fluid out side the cells = 20% • 15% in tissue space (interstitial) outside the blood vessel, between cells • 5% in plasma (intravascular space)

5. Percentage of Body Fluid

6. Fluid Balance • Normal intake 1-3 L/day • 200-300 ml produced by oxidation • Normal intake and output will balance approximately every 72 hours

7. Fluid Balance • Elimination of fluids is considered • Sensible (measurable) loss • Skin, Kidneys, Bowels, lungs lose fluid • 300-500ml lost through lungs every 24 hrs. • 500ml lost with perspiration • Insensible (not measurable) loss • Considered to be 500-1000ml/day • Lost through GI tract only 100-200 ml/day

8. Fluid Balance (cont) • Loss from Diarrhea or intestinal fistula • Significant sweat loss when body temp >101F-38.3C or room temp > 90F • When respirations > 20/min • Formula to calculate insensible loss • 300-400ml/m2/day

9. Fluid Function The fluid in the body has the following function: • Maintains blood volume • Regulates body temperature • Transports material to and from cells • Serves as an aqueous medium for cellular metabloism • Assists digestion of food through hydrolysis • Acts as a solvent in which solutes are available for cell function • Serves as a medium for the excretion of waste

10. Fluid Transport • 4 transport mechanisms • Passive transport • Passive diffusion- • Osmosis • Filtration • Active transport

11. Fluid Transport • Passive transport- non carrier mediated transport- Fluid moves through membranes with out the expenditure of energy • Passive diffusion - movement of water and other elements in all directions from high concentration to low concentration • Osmosis – passage of water from low particle concentration toward one of higher particle concentration • Normal osmolarity – 280-295 mOsm/L • Osmolarity of ICF and ECF is always equal

12. Fluid Transport (cont) • Filtration – the transfer of water and a dissolved substance from a region of high pressure to a region of low pressure. Force behind it is hydrostatic pressure (the pressure of water at rest) • Pumping heat provides hydrostatic pressure in the movement of water and electrolytes from the arterial capillary bed to the interstitial fluid.

13. Fluid Transport (cont) • Plasma protein creates and osmotic pressure at the capillary membrane, preventing fluid from plasma leaking into interstitial spaces • Osmotic pressure (created within the plasma) keeps water in the vascular system

14. Fluid Transport (cont) • Starling’s law of capillaries • Under normal circumstances fluid filtered out of the arterial end of a capillary bed and reabsorbed at the venous end is exactly the same, creating a state of near equilibrium

15. Fluid Transport (cont) • Active Transport – acts as a concentration gradient • ATP – released from the cell to enable substances to acquire the energy needed to pass through the cell membrane • Active Transport is vital for maintaining the unique composition of both the intracellular and intracellular compartments

16. Tonicity of Solution • Isotonic - .9% saline, 5% dextrose • same as body fluids • Osmolarity of 250-375mOsm/L • Remains within the ECF space • Used to expand ECF compartment

17. Isotonic Solution

18. Tonicity of Solution • Hypotonic – contains less salt than the intracellular space 2.5% DW • Osmolarity below 250mOsm/L • Hydrates cells • Depletes the circulatory system

19. Hypotonic Solution

20. Tonicity of Solution • Hypertonic – causes water from within a cell to move to the ECF compartment • Osmolarity of 375mOsm/l or greater • Used to replace electrolytes • Used to shift EDF from interstitial tissue to plasma • D5W, .9 Normal Saline

21. Hypertonic Solution

22. Homeostatic Mechanism • Regulation of body water is maintained • Exogenous sources - Intake of food & Fluids (nurse’s responsibility) • Endogenous sources – produce with in the body through chemical exidation process (various body systems responsible)

23. Homeostatic Mechanisms • Renal System – Kidneys filter 170L l of plasma/day and excrete 1.5L of urine • Regulation of fluid volume and osmolarity by selective retention and secretion of body fluid • Regulation of electrolyte levels by selective retention of needed substances and excretion of unneeded substances • Regulation of pH of ECF by excretion or retention of hydrogen ions • Excretion of metabolic wastes (primarily acids) and toxic substances

24. Homeostatic Mechanism • Cardiovascular System – • Pumping action of the heartprovides circulation of blood through the kidneys under pressure • Allow urine to form • Renal perfusion makes renal function possible

25. Homeostatic Mechanism • Lymphatic system – • Serves as an adjunct to the cardio vascular system by removing excess interstitial fluid (lymph) and returning it to the circulatory system • Prevents fluid overload

26. Homeostatic Mechanism • Respiratory System • Lungs are vital for maintaining homeostasis and constitute one of the main regulatory orgnas of fluid and acid base balance • Functions of the lungs • Regulation of metabolic alkalosis by compensatory hypoventilation • Regulation of metabolic acidosis by causing compensatory hyperventilation • Removal of 300-500 ml of water daily through exhalation

27. Homeostatic Mechanism • Nervous system • Master controller in fluid and electrolyte balance through the regulation of sodium and water • Endocrine system • Responsible for aiding homeostasis through production of various hormones • Antidiuretic hormones (ADH) • Parathyroid Hormones • Aldosterone • Epinephrine

28. Physical Assessment • Vital signs, infusion rate of IV fluids, intake and output. • Neurological - Changes in orientation, irritability, lethargy, confusion, seizures or coma • Cardiovascular – • Quality and rate of pulse • Peripheral vein filling • Orthostatic hypertension • Distended or Flat neck veins

29. Physical Assessment

30. Physical Assessment • Respiratory • Changes in respiratory rate • Tachypnea > 20/min or dysphnea indicate excess Fluid Volume (FVE) • Moist crackles (FVE) • Shallow Slow breathing- Metabolic Acidosis • Deep rapid Breathing – Metabolic Alkalosis

31. Physical Assessment • Skin Appearance & Temperature • Access skin turgor • Appearance of the tongue

32. Physical Assessment • Body Weight • Weigh Daily – better indicator than I&O records • Loss or gain of 1 kg indicates a loss or gain of 1 L of body fluid • 15% flucation is considered sever

33. Fluid Volume Imbalance • Fluid Volume Deficit • Common Causes of Isotonic Dehydration • Hemorrhage resulting in loss of fluid, electrolytes, proteins and blood cells resulting in inadequate vascular volume • Gastrointestinal losses • Fever, environmental heat, profuse sweating • Burns • Diuretics • Third spaced fluids

34. Fluid Volume Imbalance • Causes of Hypertonic Fluid Dehydration • Inadequate fluid intake • Decreased water intake results in ECF solute concentration and leads to cellular dehydration

35. Fluid Volume Imbalance • Fluid Volume Excess • Primary cause – Cardiovascular dysfunction secondary to an increase in total body sodium content • Causes of isotonic over hydration • Renal failure leading to decrease excretion of water and sodium • Heart failure leading to stasis of blood • Excess fluid intake of isotonic IV solution • High corticosteroid levels • High Aldosterone levels

36. Fluid Volume Imbalance • Common causes of Hypotonic Over hydration (Water intoxication) • More fluid is gained than solute • Serum osmolality falls causing cells to swell • Repeated water enemas • Overuse of hypotonic IV fluids • Ingestion of inappropriately prepared formula • SIADH causes kidneys to retain large amounts of water without sodium • Treatment- sodium and fluid restriction, diuretics, treat underlying cause.

37. Electrolyte Balance • Major electrolytes in body fluid are sodium, potassium, calcium, magnesium, chloride, phosphorus and bicarb • Expressed in meq/liter. Measures chemical activity or combining power rather than weight • Each water compartment of the body contains electrolytes • Concentration and composition vary from compartment to compartment

38. Electrolyte Balance (cont) • Physiological role of electrolytes • Maintaining electroneutrality in fluid compartments • Mediating enzyme reactions • Altering cell membrane permeability • Regulating muscle contraction and relaxation • Regulating nerve impulse transmission • Influencing blood clotting time

39. Electrolyte Balance (cont) • Sodium- 135 -145 mEq/L • Physiologic role of sodium: • Regulation of fluid distribution in body: water follows sodium • Maintenance of body fluid osmolarity • Promotion of neuromuscular response: Transmission of nerve and muscle impulses depends on sodium, gradient between ECF and ICF • Regulation of acid-base balance: Sodium combines with chloride and bicarbonate to alter pH

40. Electrolyte Balance (cont) • Sodium represents 90% of the extracellular cations • Serum plasma levels of electrolytes are important in the assessment and management of patients with electrolyte imbalances • Normal daily requirement 100mEq • Hyponatermia is a common complication of adrenal insufficiency • Hypernatermia – Serum Sodium excess great that 145mEq/L can occur with deprivation of water

41. Electrolyte Balance (cont) • Signs and Symptoms - Marked thirst, elevated body temperature, swollen tongue. • Chronic Hyponatremia: impaired sensation of taste, anorexia, muscle cramps, feeling of exhaustion, apprehension, feeling of impending doom and focal weakness. • Treatment: Gradually lower seum sodium level by infusion of hypotonic electrolyte solution .45 Normal Saline or D5W. Level lowered no more than 15 mEq/L in 8 hr.

42. Electrolyte Balance (cont) • Potassium: Physiological role • Regulation of fluid volume within the cell • Promotion of nerve impulse transmission • Contraction of skeletal smooth and cardiac muscle • Control of hydrogen ion concentration, acid-base balance • Role of enzyme action for cellular energy production.

43. Electrolyte Balance (cont) • Potassium is an intracellular electrolyte with 98% in ICF and 2% in the ECF • Acquired thru diet and must be ingested daily • Daily requirement is 40 mEq • Involved in muscle activity and transmission of nerve impulses.

44. Electrolyte Balance (cont) • Hypokalemia (cont)– Can cause alkalosis • S&S fatigue, muscle weakness, anorexia, nausea and vomiting, irregularity • Treatment – at level less than 3.5mEq/L replacement must be slow to prevent hyperkalemia

45. Electrolyte Balance (cont) • Hyperkalemia- Serum plasma level greater than 5.5mEq/L • Increased intake of potassium • Decreased urinary excretion • Movement out of cells into extra cellular space. • Signs & Symptoms • Changes shown on ECG • Vague muscle weakness • Flaccid paralysis • Anxiety • Nausea and vomiting • Cramping and diaherrea

46. Electrolyte Balance (cont) • Calcium: Physiological role • Maintaining skeletal elements; calcium is needed for strong bones and teeth • Regulating neuromuscular activity • Influencing enzyme activity • Converting prothrombin to thrombin, a necessary part of clotting. • 99% resides in bones and teeth

47. Electrolyte Balance (cont) • Hypocalcemia: reduction in total body calcium levels • Because of increase calcium loss, reduced intake secondary to altered intestinal absorption, altered regulation hypoparathyroidism • S & S: • Numbness of fingers, muscle cramps, hyperactive deep tendon reflexes, positive Trousseaus’s sign and Chevostek’s sign • Treatment with Calcium Gluconate oral or IV

48. Electrolyte Balance (cont) • Hyperclacemia: Excessive release of calcium from bone • S & S Neuromuscular symptoms, lethargy, bone pain, flank pain, pathological fractures, constipation, anorexia, N & V, Stone formation.

49. Electrolyte Balance (cont) • Magnesium: Physiological role • Enzyme action • Regulation of neuromuscular activity • Regulation of electrolyte balance, including facilitating transport of sodium and potassium across cell membranes, influencing the utilization of calcium, potassium, and protein. • A major intracellular electrolyte

50. Electrolyte Balance (cont) • Hypomagnesemia: often overlooked in critically ill patients • Results from: • Chronic alcoholism • Malabsorption syndrome • Prolonged malnutrition or starvation • Prolonged diarrhea • Acute pancreatitis • Administration of magnesium-free solutions for more than one week • Prolonged NG tube suctioning