Fluids-and-electrolytes-2.docx

FLUIDS AND ELECTROLYTES Prepared by: Prof. Luth M. Mondano, RN, MAN OBJECTIVES 1. Differentiate between osmosis , diffusion, filtration and active transport. 2. Describe the role of the kidneys, lungs , & endocrine glands in regulating body fluid volume and composition. 3. Discuss the mechanisms and effects of deficits and excess. 4. Describe the mechanisms that maintain acidbase balance. 5. Compare metabolic and respiratory acidosis and alkalosis with regard to causes, clinical manifestations , diagnoses & management. 6. Plan effective care of patients with different fluid volume excess and deficits. 7. Describe the cause, clinical manifestations , management, & nursing interventions of imbalances. 8. Explain the role of the lungs, kidneys and chemical buffers in maintaining acid-base balance 9. Use ABG findings in formulating the care of the patient with an acid-base imbalance. 10. Describe the management of patients with fluid, electrolyte, or acid-base imbalance. FLUID  Serve as a medium for carrying nutrients to and waste products from the cells  Means for carrying the chemical communicators that coordinate activities among cells  Transport substances such as hormones, enzymes, blood platelets, red and white blood cells  Helps maintain normal body temperature  60% or 42 liters of adult’s total body weight  Younger people have a higher % of body fluid than older people o INFANTS – 80% o ELDERLY – less muscle; thirst center diminished  Men have proportionately more body fluid than women o MALES – more muscle (muscle is 80% water) o FEMALES – more adipose tissue (fat is only 15% water) AMOUNT AND COMPOSITION OF BODY FLUIDS INTRACELLULAR FLUIDS ( ICF ) -28L • Inside the cells

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2/3 of body fluid in ICF compartment is located in the skeletal muscle mass • 55% of total body water Extracellular fluid (ECF)-14L • Outside the cells • 45% of total body water Divisions: 1. Intravascular space (the fluid within the blood vessels)  6L of blood volume is made up of plasma  remaining 3L is made up of erythrocytes, leukocytes, and thrombocytes 2. Interstitial space  contains the fluid the surrounds the cell and totals about 11-12L in an adult. Lymph is an interstitial fluid 3. Transcellular fluid space  the smallest division of the ECF compartment and contains approximately 1L  Examples: cerebrospinal, pericardial, synovial, intraocular, and pleural fluids; sweat; and digestive secretions ELECTROLYTES  Are active chemicals in body fluids (have electrical charges)  Potassium and phosphate are the major electrolytes in ICF  Sodium and chloride are the major electrolytes in ECF o Sodium level is the primary determinant of ECF concentration o Electrolyte concentration in the body is expressed in terms of milliequivalents per liter (mEq/L)

APPROXIMATE MAJOR ELECTROLYTE CONTENT IN BODY FLUID Electrolytes mEq/L Extracellular Fluid (Plasma)

Cations Sodium (Na+) Potassium (K+) Calcium (Ca++) Magnesium (Mg ++) Total cations Anions Chloride (Cl -) Bicarbonate (HCO3-) Phosphate (HPO4-) Sulfate (SO4-) Organic acids Protenaite Total anions

Electrolytes

142 5 5 2 154 103 26 2 1 5 17 154

mEq/L

Intracellular Fluid Cations

Potassium (K+) Magnesium (Mg++) Sodium (Na+) Total cations Anions Phosphates and sulfates Bicarbonate (HCO3-) Proteinate Total anions

150 40 10 200 150 10 40 200

Normal Electrolyte Values • Sodium – 135-145 mEq/L • Potassium – 3.5-5 mEq/L • Calcium – 4.5-5.5 mEq/L • Phosphorous – 1.7-2.6 mEq/L • Chloride – 98-108 mEq/L • Magnesium – 1.5-2.5 mEq/L Regulation of Body Fluid Compartments Osmosis – fluid moves across a semipermeable membrane from an area of low to an area of high solute concentration ex: homeostasis Diffusion – is the natural tendency of a substance to move from an area of higher concentration to one of lower concentration - occurs through random movement of ions and molecules

ex: exchange of oxygen and carbon dioxide in between the pulmonary capillaries and alveoli Active transport – physiologic pump that moves fluid from an area of lower concentration to an area of higher concentration - active transport requires adenosine triphosphate for energy ex: sodium potassium o Sodium concentration is greater in the ECF than in the ICF, and because of this, sodium tends to enter the cell by diffusion. o This tendency is offset by the sodiumpotassium pump that is maintained by the cell membrane and actively moves sodium from the cell into the ECF. o Conversely, the high intracellular potassium concentration is maintained by pumping potassium into the cell. Filtration – removal of particles from a solution through movement of fluid across a membrane ex: passage of water and electrolytes from the arterial capillary bed to the interstitial fluid. Sources of normal fluid loss Kidneys • Usual daily urine volume in the adult is 1-2 L • Output is approximately 1 mL of urine per kilogram of body weight per hour (1 mL/kg/h) Skin • Sensible perspiration – visible water and electrolyte loss (sweat) - 0-1,000 ml • The chief solutes in sweat are sodium, chloride, and potassium • Insensible water loss – water loss by evaporation (fever)-600ml/day Lungs • The lungs normally eliminate water vapor (insensible loss) at a rate of 300 mL every day • The loss is much greater with increased respiratory rate or depth, or in a dry climate Gastrointestinal Tract • usual loss through the GI tract is 100-200 mL daily • 8L of fluid circulates through the GI system every 24 hours Laboratory Test for Evaluating Fluid Status 1. Osmolality – measures the solute concentration per kilogram in blood and urine • Serum Osmolality - reflects the concentration of Na - 280-300 mOsm/kg

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Urine Osmolality - is determined by urea, creatinine, and uric acid - is the most reliable indicator of urine concentration - 200-800 mOsm/kg 2. Urine specific gravity - measures the kidney’s ability to excrete or conserve water - Normal range of urine specific gravity is 1.010 to 1.025 - Specific gravity varies inversely with urine volume; normally, the larger the volume of urine, the lower the specific gravity 3. BUN (Blood Urea Nitrogen) - test checks kidney function by measuring how much urea nitrogen is in the blood - Urea nitrogen is a waste product from the breakdown of protein in the body - filtered by the kidneys and leaves the body through urine - The normal BUN is 10-20 mg/dL (3.6-7.2 mmol) 4. Hematocrit - measures the number of blood cells per volume of blood - Ranges from 42% to 52% for males and 35% to 47% for females - Value increases during dehydration & polycythemia while decreased during anemia & overhydration 5. Urine sodium - Used to assess volume status - Useful in diagnosis of hyponatremia and acute renal failure - Range: 75-200 mEq/24 hrs Homeostatic Mechanisms • Keep the composition and volume of body fluid within narrow limits of normal • Organs involved in homeostasis include the kidneys, heart, lungs, pituitary gland, adrenal glands, and parathyroid glands Kidney Functions • Vital to the regulation of fluid and electrolyte balance • normally filter 180 L of plasma every day in the adult while excreting only 1-2 L of urine • Reabsorb bicarbonate (HCO3) secrete hydrogen ions (H+) in proximal and distal tubules, and produce ammonia • Compensate for imbalances more slowly than the lungs

Heart and Blood Vessel Functions • Circulates blood through the kidneys under sufficient pressure to allow for urine formation • Failure of this pumping action interferes with renal perfusion and thus with water and electrolyte regulation • Normal arterial blood gas values reflecting homeostasis include: o pH: 7.35 to 7.45 o Partial pressure of oxygen (PO2): 80 to 100 mm Hg o Partial pressure of carbon dioxide (PCO2): 35-45 mm Hg o HCO3: 22-26 mEq/L Lung Functions • Through exhalation, the lungs remove approximately 300 mL of water daily in the adult • hyperpnea (abnormally deep respiration) and continuous coughing, increase this loss • mechanical ventilation with excessive moisture decreases it • lungs have a major role in maintaining acid— base balance by controlling carbon dioxide (CO2) and carbonic acid (H2CO3) excretion Pituitary Functions • The hypothalamus manufactures ADH, which is stored in the posterior pituitary gland and released as needed • ADH maintain the osmotic pressure of the cells by controlling the retention or excretion of water by the kidneys • regulate blood volume Adrenal Functions • Aldosterone –produced in outer zone of the adrenal cortex that has a profound effect on fluid balance • Increased secretion of aldosterone causes sodium retention (and thus water retention) and potassium loss • decreased secretion of aldosterone causes sodium and water loss and Potassium retention • Cortisol - another adrenocortical hormone, has only a fraction of the mineralocorticoid potency of aldosterone; however when secreted in large quantities, it can produce sodium and fluid retention Parathyroid Functions • The parathyroid glands regulate calcium and phosphate balance by means of parathyroid hormone (PTH)

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PTH influences - bone resorption - calcium absorption from the intestines - calcium reabsorption from the renal tubules

FLUID VOLUME DISTURBANCES 1.) HYPOVOLEMIA - Fluid volume deficit (FVD), or hypovolemia, occurs when loss of ECF volume exceeds the intake of fluid - Excessive loss of water and electrolytes in equal proportion; vascular, cellular, or intracellular dehydration Causes: • abnormal fluid losses, such as those resulting from vomiting, diarrhea, GI suctioning, and sweating • decreased intake, as in nausea or lack of access to fluids • third-space fluid shifts, or the movement of fluid from the vascular system to other body spaces (eg, with edema formation in burns, ascites with liver dysfunction) Clinical Manifestations ; Signs and Symptoms of FVD: • Acute weight loss • Decreased skin turgor • Oliguria • Concentrated urine • Orthostatic hypotension • due to volume depletion • 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 Assessment and Diagnostic Findings • Urine specific gravity is above 1.020-indicating healthy renal conservation of fluid - Measures the kidneys ability to excrete or conserve urine • BUN elevated out of proportion to the serum creatinine (ratio greater than 20:1) - normal BUN 10-20 mg / dL - normal Creatinine - 0.7-1.4 mg/ dL • Hematocrit level -greater than normal

Male-42-52% Female-35-47% Urine sodium level-used to assess volume status, diagnosis of hyponatremia ,and acute renal failure - normal Urine Na level - (75-200mEq/24 hours) - As Na+ intake increases,excretion increases ; as circulating volume decreases, Na+ is conserved • Hypokalemia-occurs with GI & renal losses • Hyperkalemia-occurs with adrenal insufficiency • Hyponatremia-occurs with increased thirst and adrenal release • Hypernatremia-results from insensible losses & diabetes insipidus Medical Management • Correction of fluid loss through oral route if patient can drink • For acute or severe loss, IV route is required - Isotonic electrolyte solutions (e.g., lactated Ringer’s solution, 0.9% NaCl) are used to treat hypotensive patients with FVD - Once normotensive, hypotonic electrolyte solution (e.g., 0.45% NaCl) • Enteral or parental nutrition if oral rehydration are not tolerated Nursing Management • Monitor, measure fluid I&O at least hourly/every 8 hours • Daily body weight monitoring • Observe for weak, rapid pulse and orthostatic hypotension • Observe for body temperature • Assess for other vital signs, level of consciousness, CVP, breath sounds and skin color • Skin and tongue turgor is monitored on a regular basis • Provide frequent oral care -

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2.) HYPERVOLEMIA - Fluid volume excess (FVE), or hypervolemia, refers to an isotonic expansion of the ECF - caused by the abnormal retention of water and sodium in approximately the same proportions in which they normally exist in the ECF - secondary to an increase in total body sodium content , in turn , leads to an increase in total body water Contributing factors: • FVE may be related to simple fluid overload/ excessive fluid intake

Diminished function of the homeostatic mechanisms responsible for regulating fluid balance • Heart failure, renal failure, and cirrhosis of the liver • Consumption of excessive amounts of table or other sodium salts • Excessive administration of Na+-containing fluids in a patient with impaired regulatory mechanism Clinical Manifestations • Clinical manifestations of FVE stem from expansion of the ECF include edema, distended neck veins, and crackles (abnormal lung sounds) • Other manifestations include: o Tachycardia o Increased blood pressure, pulse pressure, and central venous pressure o Increased weight o Increased urine output o Shortness of breath and wheezing Assessment and Diagnostic Findings • BUN and hematocrit levels - decreased because of plasma dilution - Also caused by low protein intake & anemia • Serum osmolality & sodium level are decreased due to excessive retention of water in chronic renal failure • Increased urine sodium level since the kidney is attempting to excrete excess volume • Chest x-ray may reveal pulmonary congestion Management • Symptomatic treatment –administering diuretics restricting fluids and sodium 1. Nutritional Therapy - Treatment of FVE usually involves dietary restriction of sodium o mild restriction to as little as 250 mg of sodium per day o 6-15g of salt average daily diet w/o sodium restriction o Avoid foods high in sodium (canned fruits & vegs, sauces, cured meat & bacon , cheese, instant soups) o Use distilled water if water supply is high in sodium o Salt substitute contain potassium & should not be used at all in advanced renal disease because of potassium retention 2. Pharmacologic Therapy •

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Diuretics are prescribed when dietary restriction of sodium alone is insufficient to reduce edema - choice of diuretic is based on severity of hypervolemic state, degree of renal impairment and the potency of the diuretic Thiazide diuretics - prescribed for mild to moderate hypervolemia - block sodium reabsorption in the distal tubule (5-10% of filtered Na+ ) - -g.HydroDIURIL , spironolactone (Aldactone) Loop diuretics - severe hypervolemia - can cause greater loss of both water and sodium - block reabsorption in ascending limb of the loop of Henle ( 20-30%) - eg.furosemide ( Lasix ) , torsemide ( Demadex

Thiazide diuretics block sodium reabsorption in the distal tubule where only 5-10% of filtered sodium is reabsorbed • Ascending loop of Henle can cause greater loss of both sodium and water (20-30% of filtered sodium is normally reabsorbed) Side effect of diuretics • Electrolyte imbalances-result from the effect of diuretic • Hypokalemia • Hyperkalemia • Hyponatremia • Hypomagnesemia • Azotemia-(increased nitrogen level) • High uric acid levels (hyperuricemia) 3. Dialysis Hemodialysis -to remove nitrogenous wastes and control potassium and acid–base balance , and to remove sodium and fluid. •

Nursing Management • Measure l&O at regular intervals to identify excessive fluid retention • Weigh patient daily to note rapid weight gain (acute weight gain of 1 kg represents a gain of 1L of fluid) • Monitor the degree of edema in the most dependent parts of the body Pitting edema - press the finger into the affected part creating a pit or indentation evaluated on a scale of 1 (minimal) to 4 (severe) - check feet and ankles in ambulatory patients and the sacral region in bedridden patient Peripheral edema - monitored by measuring the circumference of the extremity with a tape marked in mm • Assess breath sounds at regular intervals in at-risk patients, particularly when parenteral fluids are being administered - If pulmonary edema occurs, elevate the head of the bed and have the client turn, cough, and deep-breathe every 2 hrs • Turn the client every 2 hrs to prevent skin breakdown

Nursing Alert When administering fluids to patients with cardiovascular disease, the nurse assesses for signs of circulatory overload. The lungs are auscultated for crackles. • Cough • Dyspnea • puffy eyelids • dependent edema • weight gain in 24 hours ELECTROLYTE IMBALANCES 1.) Sodium Imbalances Sodium is the most abundant electrolyte In ECF - Concentration ranges from 135 to 145 mmol/L - Primary determinant of ECF volume and osmolality - Has a major role in controlling water distribution throughout the body - Regulated by ADH, thirst, and the reninangiotensin-aldosterone system - A loss or gain of sodium is usually accompanied by a loss or gain of water

Necessary for muscle contraction and the transmission of nerve impulses - Syndrome of inappropriate antidiuretic hormone (SIADH) excretion is associated with sodium imbalance Causes of SIADH • Excessive ADH activity • Hyponatremia • Hypernatremia • Conditions affecting the CNS -

HYPONATREMIA (Sodium Deficit) • Sodium level that is below normal (less than 135 mmol/L) • Total sodium concentration represents the ratio of total body sodium to total body water: - Low total body sodium with a lesser reduction in total body water - Normal total body sodium content with excesss of total body water - Excess total body sodium with an even greater excess of total body water • Can be superimposed on an existing FVD or FVE Causes: • Vomiting, diarrhea, diaphoresis, and nasogastric suctioning • Diuretic use • Adrenal insufficiency • Use of certain anticonvulsant medications: carbamazepine (Tegretol ) , levetiracetam (Keppra ) ,fluoxetine ( Sarafem ) • SIADH-abnormal water retention Clinical Manifestations Clinical manifestations of hyponatremia depend on the cause, magnitude, and speed with which the deficit occurs • Poor skin turgor • dry mucosa • decreased saliva production • nausea • vomiting • abdominal cramping • orthostatic fall in blood pressure • Altered mental status • Status epilepticus: epileptic seizures follow one another without recovery of consciousness bet them • Coma • Lethargy • Confusion • Muscle twitching

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Hemiparesis: one-sided muscle weakness or paralysis • seizures ASSESSMENT AND DIAGNOSTIC FINDINGS • Serum osmolality –decreased • Serum sodium –less than 135 mEq/ L ; lower than 100 in SIADH • Hyponatremia due to Sodium loss- Urinary Sodium-less than 20 mEq/ L & low specific gravity (1. 002- 1.004) due to SIADH - Urinary Sodium-greater than 20mEq / L & specific gravity greater than 1.012 • ECF volume increased without any edema • Anorexia • Muscle cramps • Exhaustion  Acute decrease in sodium in less than 24hrsassociated with brain herniation & compression of midbrain structures  Chronic decrease in sodium over 48hrs can occur in status epilepticus Medical Management • IV conivaptan hydrochloride (Vaprisol) for patients with moderate to severe symptomatic hyponatremia • Hypertonic saline for patients with delirium or coma • Lithium ( Eskalith ) to antagonize the osmotic effect of ADH Nursing Management • Monitoring fluid I&O for patients at risk • Daily body weighing to note abnormal losses of sodium or gains of water. • Encourage foods and fluids with a high sodium content, such as beef broth and tomato juice • Prevent injury - Central nervous system (CNS) changes: lethargy, confusion, muscle twitching and seizures • Watch for neurologic sign : - muscle weakness - partial or complete loss of sensation - poor cognitive abilities - decreased alertness - difficulty reading and writing • Watch for increased risk for hyponatremia among elderly - changes in renal function - subsequent decreased ability to excrete excessive water loads - diminished sense of thirst

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loss of access to food or fluids

HYPERNATREMIA (Sodium Excess) - Sodium level higher-than 145 mEq/L or 145 mmol/L - Can occur in patients with normal fluid volume or in those with FVE or FVD Causes:  Gain of sodium in excess of water or by a loss of water in excess of sodium  Fluid deprivation in unconscious patients who cannot perceive, respond to, or communicate their thirst  Administration of hypertonic enteral feedings without adequate water supplements  Watery diarrhea  Insensible water loss (hyperventilation, denuding effects of burns) Clinical Manifestations The clinical manifestations of hypernatremia are primarily neurologic • Restlessness and weakness in moderate hypernatremia • Disorientation, delusions, and hallucinations in severe hypernatremia • In severe hypernatremia, permanent brain damage can happen due to hemorrhages from brain contraction • Dehydration • Thirst ( primary characteristic of hypernatremia) • Central and nephrogenic diabetes insipidus • Less common causes: • Heat stroke • Near drowning in sea water • Malfunction of hemodialysis or peritoneal dialysis system • IV administration of hypertonic saline • Excessive use of sodium bicarbonate: antacid for heartburn and indigestion Other Signs: • dry swollen tongue • sticky mucous membranes • flushed skin • Body temperature may rise mildly • peripheral and pulmonary edema: fluid retention & accumulation • postural hypotension: ↓ blood volume in ECF • increased muscle tone and deep tendon reflexes

Assessment and Diagnostic Findings • In HYPERNATREMIA, the serum sodium level exceeds 145 mEq/L. and the serum osmolality exceeds 300 mmol/L • The urine specific gravity and urine osmolality are increased • Patients with nephrogenic or central diabetes insipidus (caused by insufficient levels of antidiuretic hormone (ADH)/Arginine Vassopressin) produce a dilute urine with a urine osmolality > 250 mmol/kg Medical Management • Hypotonic electrolyte solution (e.g, 0.3% sodium chloride): allows a gradual reduction in the serum sodium level and thereby decreases the risk of cerebral edema • Isotonic non saline solution (e.g. 5% dextrose in water): D5W is indicated when water needs to be replaced without sodium • Diuretics also may be prescribed to treat the sodium gain Nursing Management • Intake and output measurement • Advise client to avoid over-the-counter medications with a high sodium content (such as Alka-Seltzer) • Educate on foods rich in sodium to avoid: - canned fruits & vegetables - processed foods - instant soups - sauces & dressings - cheese - fastfood fries & burgers • Note the patient’s thirst or elevated body temperature • Monitor for changes in behaviour, such as restlessness, disorientation, and lethargy • Provide fluids at regular intervals, particularly in debilitated patients unable to perceive or respond to thirst • Protect client from injury 2.) Potassium Imbalances - Potassium is the major intracellular electrolyte 98% of the body’s potassium is inside the cells. - The remaining 2% is in the ECF that is important in neuromuscular function Potassium influences both skeletal and cardiac muscle activity

Normal serum concentration level- 3.5-5.0 mEq/ L - 80% of the potassium is excreted daily from the body by way of the kidneys - 20% is lost through the bowel & in sweat - Alterations in its concentration change myocardial irritability and rhythm - Potassium imbalances are commonly associated with:  various diseases, injuries  medications (NSAIDs , ACE inhibitors)  special treatments such as parenteral nutrition and chemotherapy Kidneys maintain K+ balanc As serum potassium levels increase, so does the potassium level in the renal tubular cel Aldosterone also increases the excretion of potassium by the kidne Kidneys do not conserve potassium as well as they conserve sodium -

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HYPOKALEMIA (Potassium Deficit) - Hypokalemia (below-normal serum potassium concentration 3.5 mEq/L) - usually indicates an actual deficit in total potassium stores - When alkalosis is present, a temporary shift of serum potassium into the cells occurs Causes: • Use of diuretics • Other medications that can lead to hypokalemia include: corticosteroids, sodium penicillin, carbenicillin, and amphotericin • Vomiting • Diarrhea • Prolonged intestinal & gastric suctioning • Recent ileostomy • Villous adenoma • Alterations in acid—base balance • Respiratory or metabolic alkalosis • Hyperaldosteronism increases renal potassium wasting • Anorexia nervosa • Bulimia Clinical Manifestations • Decreased bowel motility • Anorexia, nausea, and vomiting • Muscle weakness • Leg cramps • Paresthesias(numbness & tinggling) • Polyuria ,nocturia & excessive thirst • Glucose intolerance

• Dysrhythmias • Increased sensitivity to digitalis • Decreased muscle strength & DTRs ASSESMENT and DIAGNOSTIC FINDINGS • ECG changes • Digitalis toxicity • Symptoms of digitalis toxicity:  Confusion  Irregular pulse  Loss of appetite  Nausea, vomiting, diarrhea  Fast heartbeat  Vision changes (unusual), including blind spots, blurred vision, changes in how colors look, or seeing spots) • Metabolic alkalosis • 24-hour urinary potassium excretion test ( to determine between renal and extrarenal loss)

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Changes on an electrocardiogram (ECG) can include flat T waves and/or inverted T waves, suggesting ischemia, and depressed ST segments • An elevated U wave is specific to hypokalemia Medical Management • Conventional measure –increase oral intake • Oral K+ supplements • IV supplements: KCL, potassium acetate , potassium phosphate • Potassium loss must be corrected daily (administration of 40-80 mEq of potassium in the adult) Nursing Management • Monitor for its early presence in patients at risk

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Monitor closely for signs of digitalis toxicity, because hypokalemia potentiates the action of digitalis • Assess for abdominal distention, pain, or GI bleeding (dark tarry stool & coffee ground vomitus) which may indicate bowel lesions • Monitor intake and output accurately • Intake of potassium-rich foods: fruits, fruit juices, dried fruits, fresh or frozen vegetables, legumes. whole grains, milk, eggs, meat, and poultry • Maintain a safe environment NURSING ALERT • Oral potassium can produce small bowel lesions; therefore , the patient must be assessed for and cautioned about abdominal distention • Potassium supplements are extremely dangerous for patients who have impaired renal function and thus decreased ability to excrete potassium. • Intravenous potassium is never administered by IV push or intramuscularly to avoid replacing potassium too quickly • Aged ( stored ) blood should not be administered to patients with impaired renal function because the serum potassium concentration of stored blood increases due to red blood deterioration • Potassium should be administered only after adequate urine flow has been established HYPERKALEMIA (Potassium Excess) - Greater than normal serum potassium concentration 5.0 mEq/L - Cardiac arrest is more frequently associated with high serum potassium levels Causes: • Three major causes: • Decreased renal excretion of potassium • Rapid administration of potassium • Movement of potassium from the ICF compartment to the ECF Other causes: • Infection –use of trimethoprim & pentamidine • Excessive intake of potassium in food or medications • Hypoaldosteronism/ Addison’s Disease • Medications: potassium chloride, heparin, ACE inhibitors, NSAIDs, beta-blockers, and potassium-sparing diuretics

Acidosis: potassium moves out of the cells and into the ECF • Pseudohyperkalemia: the use of a tight tourniquet around an exercising extremity while drawing a blood sample, and producing hemolysis of the sample before analysis Clinical Manifestations • Disturbances in cardiac conduction - Peaked, narrow T-waves; ST-segment depression; and a shortened QT interval • Skeletal muscle weakness and even paralysis: Hyperkalemia can cause ascending muscle weakness that begins with the legs and progresses to the trunk and arms • Flaccid quadriplegia: paralysis caused by illness or injury that results in the partial or total loss of use of all four limbs • Paralysis of respiratory and speech muscles • GI manifestations - nausea, intermittent intestinal colic, and diarrhea Assessment and Diagnostic Findings • Serum potassium levels-elevated • ECG changes –conduction disturbance • Arterial blood gas analysis (reveal both a metabolic and respiratory acidosis) Medical Management • Restriction of dietary potassium • Potassium-containing medications (eg. Kayexalate enema) • IV Calcium gluconate – • IV sodium bicarbonate and hypertonic dextrose • .Lasix • Beta 2 agonist like albuterol ( Ventolin) • Hemodialysis Nursing Management • Observe for signs of muscle weakness and paresthesias • Observe for GI symptoms such as nausea and vomiting • Encourage to adhere to the prescribed potassium restriction • Educate about potassium rich foods that they have to avoid like: - banana - Kiwi - prune juice - Papaya - Honeydew melon - Raisins - orange & juice - Cantaloupe • Salt substitutes should not be administered to patients with renal dysfunction •

3.) Calcium Imbalances

Calcium - Plays a major role in transmitting nerve impulses - Helps regulate muscle contraction, and relaxation, including cardiac muscle - Activates enzymes & plays a role in blood coagulation • More than 99% of the body’s calcium is located in the skeletal system • 1% circulates in the serum, partly bound to protein partly ionized • Normal level- 8.6 to 10.2 mg/dL (2.2 to 2.6 mmol/L) Calcium exists in plasma in three forms: • Ionized o active ionized – important for neuromuscular activity & blood coagulation o normal ionized -4.5-5.1 mg/dL  Bound to protein primarily albumin • Complexed – combined with nonprotein anions: phosphate , citrate & carbonate  Absorbed with foods in the presence of normal gastric acidity & Vitamin D  Excreted primarily in the feces & the remainder excreted in the urine  Serum Ca+ level is controlled by PTH & calcitonin  As ionized serum Ca+ decreases , the parathyroid glands secrete PTH  The increase in Ca+ ion concentration suppresses PTH secretion  When Ca+ increases excessively, the thyroid gland secretes calcitonin which inhibits reabsorption from bone & decreases the serum calcium concentration HYPOCALCEMIA (Calcium Deficit) - Lower than 8.6 mg/dL (2.15 mmol/L) - May have a total body calcium deficit but with a normal serum calcium level - Increased amount of time in bed Causes: • Primary hypoparathyroldism: • Surgical hypoparathyroidism • Radical neck dissection-24 to 48hrs after surgery • Transient hypocalcemia • Pancreatitis • Renal failure • Hyperphosphatemia- causes a reciprocal drop in the serum calcium level

Inadequate vitamin D consumption Alkalosis alcohol abuse Medications predisposing to hypocalcemia include - Aluminum-containing antacids - Aminoglycosides - caffeine - cisplatin: chemotherapy drug - Corticosteroids - Phosphates - Isoniazid - loop diuretic Clinical Manifestations • Tetany- condition marked by intermittent muscular spasms, tingling in fingers ,around the mouth & feet • Trousseau’s sign - can be elicited by inflating a blood pressure cuff on the upper arm to about 20 mm Hg above systolic pressure; within 2 -5 minutes, carpal spasm (an adducted thumb, flexed wrist and metacarpophalangeal joints, extended interphalangeal joints with fingers together) • Chvostek’s sign - consists of twitching of muscles supplied by the facial nerve when the nerve is tapped about 2 cm anterior to the earlobe, just below the zygomatic arch • Seizures • Mental changes - depression, impaired memory, confusion, delirium, and even hallucinations • Osteoporosis • Dyspnea, laryngo & bronchialspasm CHRONIC HYPOCALCEMIA: • Hyperactive bowel sound • Dry brittle hair & nails • Abnormal clotting Assessment And Diagnostic Findings • Serum calcium levels • PTH levels- decreased in hypoparathyroidism • ECG • Magnesium & Phosphorus levels Medical Management • IV administration of calcium - calcium gluconate, calcium chloride, and calcium gluceptate • Vitamin D therapy may be instituted to increase calcium absorption from the GI tract • • • •

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Aluminum hydroxide, calcium acetate, or calcium carbonate antacids may be prescribed to decrease elevated phosphorus levels before treating hypocalcemia for the patient with chronic renal failure Nursing Alert: IV Calcium Administration • dangerous in patients receiving digitalisderived medications • can cause digitalis toxicity, with adverse cardiac effects • Too-rapid administration can cause cardiac arrest, preceded by bradycardia • IV calcium should be diluted in D5W and given as a slow IV bolus or a slow IV infusion using a volumetric Infusion pump • A 0.9% sodium chloride solution should not be used with calcium, because it will increase renal calcium loss • Solutions containing phosphates or bicarbonate should not be used with calcium, as they will cause precipitation when calcium is added • Calcium can cause postural hypotension; monitor blood pressure Nursing Management • Seizure precaution • Health teachings to avoid the following: - Caffeine in high doses- inhibit calcium absorption - Cigarette smoking- increases urinary calcium excretion - overuse of laxatives and antacidsdecreases calcium absorption • Increase dietary intake of calcium: 1500mg/day - Foods rich in calcium: milk products, green leafy vegetables, fresh oysters • Instruct client on the value of regular exercise- decreases bone loss • Calcium supplements should be taken in divided doses with meals • Caution to avoid overuse of laxatives & antacids that contain Phosphorus • Check BP • Auscultate lungs HYPERCALCEMIA (Calcium Excess) - Greater than 10.2 mg/dL (2.6 mmol/L) - has a mortality rate as high as 50% if not treated promptly Causes: • Hyperparathyroidism • Malignant tumors

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Prolonged immobilization Thiazide diuretics Vitamin A and D intoxication, as well as the use of lithium Clinical Manifestation • Anorexia, nausea, vomiting • Constipation • Dehydration • Abdominal and bone pain • Abdominal distention and paralytic ileus • Excessive urination • Severe thirst • Altered level of consciousness - Slurred speech, confusion, lethargy, coma • Hypercalcemic crisis- an acute rise in the serum calcium level to 17 mg/dL (4.3 mmol/L) or higher Assessment and Diagnostic Finding • Serum calcium level greater than 10.2 mg/dL (2.6 mmol/L) - Dysrhthmias- shortening of the QT interval, and ST segment • Double antibody PTH test- to differentiate between primary hyperthyroidism and malignancy as a cause of hypercalcemia • X-rays reveal bone changes • Sulkowitch urine test- analyzes amount of calcium in the urine Medical Management • IV administration 0.9% sodium chloride solution • Administering IV phosphate • Furosemide (Lasix) is often used in conjunction with administration of saline solution • Calcitonin • Surgery, chemotherapy, or radiation therapy for patients with cancer • Corticosteroids • Mithramycin • Inorganic phosphate salts ( Phospho-soda or Neutra-Phos), rectally (as retention enemas), or intravenously • IV phosphate therapy Nursing Alert: Calcitonin • Skin testing for allergy to salmon calcitonin is necessary before the hormone is administered • Systemic allergic reactions are possible since this hormone is a protein - Resistance to the medication may develop later because of antibody formation

Administered by intramuscular injection rather than subcutaneously Nursing Management • Institute injury prevention measures for mental confusion - Keep bedside rails up - Keep bed brakes locked • Increasing patient mobility and encouraging fluids can help prevent hypercalcemia or at least minimize its severity • Fluids containing sodium should he administered unless contraindicated • Patients are encouraged to drink 3 to 4 quarts of fluid daily • Adequate fiber should be provided • Assess for signs and symptoms of digitalis toxicity • Monitor cardiac rate and rhythm for any abnormalities- ECG changes can occur •

4.) Magnesium Imbalances - Next to potassium, magnesium is the most abundant intracellular cation - acts as an activator for many intracellular enzyme systems - plays a role in both carbohydrate and protein metabolism - Normal serum magnesium level is 1.3 to 2.3 mg/dL (0.62 to 0.95mmol/L) • Magnesium balance is important in neuromuscular function • Approximately one third is bound to protein ;the remaining two thirds exists as free cations • Excess of Mg++ diminishes excitability of muscle cells • Deficit increases neuromuscular irritability & contractility • Mg status depends on 3 organs: uptake in the intestine, storage in the bone and excretion in the kidneys. Hypermagnesemia is therefore often due to problems in these organs, mostly intestine or kidney. • Mg++ produces sedative effect at neuromuscular junction - It stimulates threshold in nerve fibers - Affects the cardiovascular system to produce vasodilation & decreased peripheral resistance - Found in bone & soft tissues - Eliminated by the kidney HYPOMAGNESEMIA (Magnesium Deficit)

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Below normal serum magnesium concentration- 1.3 mg/dL (0.62 mmol/L) Magnesium is similar to calcium in two ways:  Ionized Mg++ involved in neuromuscular activity and other physiologic processes  Magnesium levels should be evaluated in combination with albumin level About 30% of magnesium is protein bound, principally to albumin A decreased albumin level can reduce the measured total magnesium concentration

Causes: • *An important route of Mg++ loss is the GI tract • Loss of magnesium from the GI tract may occur with nasogastric suction, diarrhea, or fistulas • Disruption in small bowel function (eg. intestinal resection or inflammatory bowel disease) • Withdrawal from alcohol and administration of tube feedings or parenteral nutrition • Enteral or parenteral feeding deficient in Mg++ • Other causes include: - Administration of aminoglycosides, cyclosporine, cisplatin, diuretics, digitalis, and amphotericin - Rapid administration of citrated blood, especially to patients with renal or hepatic disease • Diabetic ketoacidosis: serious complication of diabetes that occurs when your body produces high levels of blood acids called ketones • Other contributing causes: pregnancy, lactation, sepsis, burns, and hypothermia Clinical Manifestations • Symptoms do not usually occur until the serum magnesium level is less than 1 mEq/L (0.5 mmol/L) • Manifestations are largely confined to the neuromuscular system • Hyperexcitability with muscle weakness, tremors, and athetoid movements (slow, involuntary twisting ) • Others include:  Tetany  Nystagmus: involuntary, rapid and repetitive movement of the eye

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Vertigo: sensation of spinning that is related to problems with the inner ear  Generalized tonic-clonic or focal seizures - Tonic-clonic seizure A person loses consciousness, muscles stiffen, and jerking movements are seen.Involves the whole body These types of seizures usually last 1 to 3 minutes and take much longer for a person to recover - Partial (focal) seizures occur when this electrical activity remains in a limited area of the brain  laryngeal stridor  Positive Chvostek’s and Trousseau’s signs  Cardiac dysrhythmias  Marked alterations in mood-apathy ,depression , ataxia , confusion  Insomnia  Dysphagia Assessment and Diagnostic Findings • Serum magnesium level- less than 1.3 mg/dL (0.62 mmol/L) • Urine magnesium after a loading dose of magnesium sulphate • Two newer diagnostic techniques: - nuclear magnetic resonance spectroscopy - ion-selective electrode Medical Management • Diet for mild magnesium deficiency - Sources: green leafy vegetables, nuts, legumes, whole grains, peanut butter, cocoa, and seafoods • Mg++ oral salts in oxide or gluconate forms • IV parenteral administration with magnesium sulfate not to exceed 150 mg/min or 67mEq over 8 hours by infusion pump Nursing Alert: Magnesium IV injection given slowly • Rate: not to exceed 150 mg/min, or 67 mEq over 8 hours • Can produce alterations in cardiac conduction • Assess vital signs frequently- hypotension, respiratory distress • Monitoring urine output is done before, during, and after magnesium administration • Calcium gluconate must be readily available to treat hypocalcemic tetany or hypermagnesemia