Fluid and Electrolytes 172022 1 Compartments Intracellular fluid

Fluid and Electrolytes ( 1/7/2022 1

Compartments Intracellular fluid (ICF) ¡ Extracellular fluid (ECF) ¡ Intravascular (plasma) ¡ Interstitial ¡ ¡ Transcellular See Figure 16 -2 in Lewis 6 th ed. 1/7/2022 2

Intracellular Fluid (ICF) l Fluid located within cells l 42% of body weight l Potassium (K+) is the most prevalent cation inside the cell l Phosphate (PO 4 -) is the most prevalent anion 1/7/2022 3

Extracellular Fluid (ECF) (between cells; in the plasma space) ¡ Interstitial (between cells) l l 1/7/2022 (Cl-) is most prevalent anion (Na+) is most prevalent cation expands and contracts 2/3 of ECF is in interstitial 4

Extracellular Fluid (ECF) ¡ Intravascular (IV) Within vascular space ¡ Measured with blood tests ¡ 1/3 of ECF ¡ ¡ Transcellular Small but important fluid compartment ¡ Approximately 1 Litre ¡ 1/7/2022 5

Transcellular Fluid ¡ Includes fluid in the: ¡ Cerebrospinal fluid ¡ Gastrointestinal (GI) tract ¡ Pleural spaces ¡ Synovial spaces ¡ Peritoneal fluid spaces 1/7/2022 6

Mechanisms Controlling Fluid and Electrolyte Movement ¡ Diffusion l ¡ Facilitated diffusion l ¡ molecules move from high to low concentration involves carrier molecules Active transport l 1/7/2022 movement against concentration gradient; requires energy 7

Mechanisms Controlling Fluid and Electrolyte Movement ¡ Osmosis l ¡ Hydrostatic pressure l ¡ H 2 o movement between compartments separated by membrane from area of high solute concentration to low solute concentration; permeable to water, but not solutes force within fluid compartment Oncotic pressure l 1/7/2022 osmotic pressure exerted by colloids [e. g. , protein] n solution; “pulls” fluid into vascular space 8

Fluid Shifts: Plasma to interstitial space ¡ ¡ Results in edema Due to: l Elevated venous hydrostatic pressure ¡ l Decreased plasma oncotic pressure ¡ l e. g. , low plasma protein r/t malnutrition Elevated interstitial oncotic pressure ¡ 1/7/2022 e. g. , CHF, varicose veins plasma proteins accumulated in interstitium, pulling water - e. g. , burns 9

Fluid Movement Between Extracellular and Intracellular ¡ ¡ ¡ Excess water in ECF: Water moves into cells → Cells swell Water deficit in ECF : water is pulled from cells → Cells shrink Both of above cause neurological symptoms 1/7/2022 10

Fluid Spacing ¡ First spacing l ¡ Second spacing l ¡ Abnormal accumulation of interstitial fluid (i. e. , edema) Third spacing l 1/7/2022 Normal distribution of fluid in ICF and ECF Fluid accumulation in part of body where it is not easily exchanged with rest of ECF (e. g. , edema due to burns, ascites) 11

Regulation of Water Balance Hypothalamic regulation ¡ Pituitary regulation (ADH) ¡ Adrenal cortical regulation ¡ Renal regulation ¡ Cardiac regulation ¡ Gastrointestinal regulation ¡ Insensible water loss ¡ 1/7/2022 12

Insensible Water Loss ¡ Invisible vaporization from lungs and skin ¡ Approximately 900 ml per day is lost ¡ No electrolytes are lost with insensible water loss l 1/7/2022 Excessive sweating is not an insensible loss. Diaphoresis leads to loss of water and electrolytes. 13

Sodium 1/7/2022 ¡ Plays major role in maintaining ECF concentration (osmolality) and volume ¡ Main cation in ECF; primary determinant of osmolality (a measure of solute concentration) ¡ Important in generation and transmission of nerve impulses ¡ Important acid-base balance 14

Hypernatremia ¡ Elevated serum sodium occurs with water loss or sodium gain ¡ Causes hyperosmolality → water shifts out of cells → cellular dehydration ¡ Primary protection is thirst from hypothalamus 1/7/2022 15

Hypernatremia ¡ ¡ ¡ 1/7/2022 Manifestations include thirst, lethargy, agitation, seizures, and coma Hypernatremia secondary to water deficiency often due to impaired LOC or inability to get fluids Also due to deficiency in ADH 16

Hypernatremia ¡ Management includes: l l l ¡ 1/7/2022 Treating the underlying cause IV solution of 5% dextrose in water or hypotonic saline, if oral fluids cannot be ingested Administering diuretics (promotes excretion of sodium) Serum sodium levels must be reduced gradually to avoid cerebral edema 17

Hyponatremia ¡ Due to: l l 1/7/2022 loss of Na-containing fluids, or water excess (dilutional hyponatremia) ¡ Hyponatremia → hypoosmolality → water moves into cells ¡ Clinical manifestations include confusion, nausea, vomiting, seizures, and coma 18

Hyponatremia ¡ ¡ 1/7/2022 If caused by water excess, fluid restriction is needed If severe symptoms (seizures) occur, small amount of intravenous hypertonic saline solution (3% Na. Cl) is given 19

Hyponatremia ¡ If associated with abnormal fluid loss (diarrhea, polyuria, etc. ): Ø fluid replacement with Nacontaining solution (eg. Normal saline [0. 9% Na. Cl]) 1/7/2022 20

Potassium ¡ Potassium major ICF cation ¡ Potassium is necessary for l l 1/7/2022 Transmission and conduction of nerve impulses Maintenance of normal cardiac rhythms Skeletal muscle contraction Acid-base balance 21

Potassium ¡ Critical to action membrane potential l 1/7/2022 Sources ¡ Fruits and vegetables (bananas and oranges) ¡ Salt substitutes ¡ Potassium medications (PO, IV) ¡ Stored blood 22

Hyperkalemia ¡ Causes l l l 1/7/2022 Increased retention ¡ Renal failure ¡ Potassium sparing diuretics Increased intake Mobilization from ICF ¡ Tissue destruction ¡ Acidosis 23

Hyperkalemia Clinical Manifestations ¡ ¡ ¡ 1/7/2022 Skeletal muscles weak or paralyzed Ventricular fibrillation or cardiac standstill Abdominal cramping or diarrhea 24

Nursing Management Nursing Implementation Eliminate oral and parenteral K intake ¡ Increase elimination of K (diuretics, dialysis, Kayexalate) ¡ Force K from ECF to ICF with IV insulin or sodium bicarbonate ¡ 1/7/2022 25

Hypokalemia ¡ Causes l Increased loss ¡ Certain diuretics ¡ GI losses ¡ Associated with Mg deficiency ¡ Movement into cells 1/7/2022 26

Hypokalemia Clinical Manifestations Potentially lethal ventricular arrhythmias ¡ Increased digoxin toxicity in those taking the drug ¡ Skeletal muscle weakness and paralysis ¡ Muscle cell breakdown ¡ l 1/7/2022 Leads to presence of myoglobin in plasma and urine 27

Hypokalemia Clinical Manifestations ¡ Decreased GI motility ¡ Altered airway responsiveness ¡ 1/7/2022 Impaired regulation of arterial blood flow ¡ Diuresis ¡ Hyperglycemia 28

Nursing Management Nursing Implementation ¡ Replacement PO or IV l l l ¡ 1/7/2022 Never push IV Painful in peripheral veins Never give with anuric renal failure Teach prevention methods 29

Electrolyte Disorders Summary Signs and Symptoms 1/7/2022 Electrolyte Excess Deficit Sodium (Na) Hypernatremia Thirst CNS deterioration Increased interstitial fluid Hyponatremia CNS deterioration Potassium (K) Hyperkalemia Ventricular fibrillation ECG changes CNS changes Hypokalemia Bradycardia ECG changes CNS changes 30

Electrolyte Disorders Signs and Symptoms Electrolyte Excess Deficit Calcium (Ca) Hypernatremia Thirst CNS deterioration Increased interstitial fluid Hypocalcemia Tetany Chvostek’s, Trousseau’s Muscle twitching CNS changes EKG changes Magnesium (Mg) Hypermagnesemia Loss of deep tendon reflexes (DTRs) Depression of CNS Depression of neuromuscular function Hypomagnesemia Hyperactive deep tendon reflexes CNS changes EKG changes 1/7/2022 31

Protein Imbalances ¡ ¡ 1/7/2022 Plasma proteins, particularly albumin, are significant determinants of plasma volume Hyperproteinemia is rare, but occurs with dehydration-induced hemoconcentration 32

Hypoproteinemia ¡ Caused by l l l 1/7/2022 Anorexia Malnutrition Starvation Fad dieting Poorly balanced vegetarian diets 33

Hypoproteinemia ¡ ¡ ¡ 1/7/2022 Poor absorption can occur in certain GI malabsorptive diseases Protein can shift out of intravascular space with inflammation Hemorrhage 34

Clinical Manifestations of Hypoproteinemia Edema ¡ Slow healing ¡ Anorexia ¡ Fatigue ¡ Anemia ¡ Muscle loss ¡ Ascites ¡ 1/7/2022 35

Hypoproteinemia ¡ 1/7/2022 Management l High-carbohydrate, high-protein diet l Dietary protein supplements l Enteral nutrition or total parenteral nutrition 36

Extracellular Fluid Volume Imbalances ¡ ¡ 1/7/2022 Hypovolemia can occur with loss of normal body fluids (diarrhea, fistula drainage, hemorrhage), decreased intake, or plasma-to-interstitial fluid shift Hypervolemia may result from excessive intake of fluids, abnormal retention of fluids (CHF), or interstitial-to-plasma fluid shift 37

Extracellular Fluid Volume Imbalances ¡ ¡ 1/7/2022 Treatment for hypovolemia is balanced IV solutions, isotonic chloride, or blood Treatment for hypervolemia is use of diuretics, fluid restriction, and sodium restriction 38

Nursing Management Nursing Diagnoses: Hypervolemia l l l 1/7/2022 Excess fluid volume Ineffective airway clearance Risk for impaired skin integrity Disturbed body image PC: pulmonary edema, ascites 39

Nursing Management Nursing Diagnoses: Hypovolemia 1/7/2022 l Fluid volume deficit l Decreased cardiac output l PC: hypovolemic shock 40

Nursing Implementation for Volume Imbalances 1/7/2022 ¡ I&O ¡ Cardiovascular status (BP, pulse strength, JVD, HR, orthostatic hypotension) ¡ Respiratory status (crackles, RR) ¡ Neurological function ¡ Daily weights (1 kg = 1000 ml) ¡ Skin assessment (turgor, edema) 41

Nursing Implementation for Volume Imbalances ¡ Neurologic function l l l 1/7/2022 LOC PERLA Voluntary movement of extremities Muscle strength Reflexes 42

IV Fluids Purposes 1. Maintenance ¡ 2. Replacement ¡ 1/7/2022 When oral intake is not adequate When losses have occurred 43

Solution Types ¡ Hypotonic l l l 1/7/2022 Provides more water than electrolytes Dilutes ECF, thus water moves from ECF → ICF Examples: 0. 45 Na. Cl 44

Solution Types ¡ Isotonic l l l 1/7/2022 Same osmolality as ECF Expands only ECF (what goes in ECF stays in ECF; no shifting to ICF) Examples: Normal saline (0. 9% Na. Cl), Lactated Ringers (Ringer’s Lactate) 45

Solution Types ¡ Hypertonic l l l 1/7/2022 More concentrated than ECF Expands ECF volume Increased osmolality draws water from cells into ECF 46

D 5 W ¡ Isotonic (Hypotonic after dextrose is metabolized) ¡ A source of calories ¡ Free water l l 1/7/2022 Moves into ICF Increases renal solute excretion 47

D 5 W ¡ ¡ 1/7/2022 Prevents ketosis Supports edema formation –Do not use in clients with cerebral edema! Decreased chance of IV fluid overload Usually compatible with medications 48

Normal Saline (NS; 0. 9% Na. Cl) 1/7/2022 ¡ Isotonic ¡ No calories ¡ More Na. Cl than ECF 49

Normal Saline (NS; 0. 9% Na. Cl) ¡ Expands IV volume l l 1/7/2022 Preferred fluid for immediate response Risk for fluid overload higher ¡ Does not change ICF Volume ¡ Blood products ¡ Compatible with most medications 50

Lactated Ringer’s ¡ Isotonic ¡ More similar to plasma than NS (b/c has electrolytes) l 1/7/2022 Commonly used postoperatively ¡ Expands ECF, IV ¡ Common replacement fluid 51

D 5 ½ NS ¡ ¡ ¡ 1/7/2022 Hypertonic (becomes Hypotonic in body after dextose is absorbed) Common maintenance fluid KCl added for maintenance or replacement 52

D 5 ½ NS (Hypertonic) ¡ Provides calories l 1/7/2022 Prevents ketosis ¡ Moves into ICF ¡ Usually compatible with medications 53

Plasma Expanders (Hypertonic) Pull fluid from interstitium into vascular space ¡ Colloids ¡ l l l 1/7/2022 Packed RBCs Albumin Plasma 54