Drugs for Fluid and Electrolyte Imbalances and Acid-Base Disorders PDF

Restricted and Non- Sensitive Drugs for Fluid and Electrolyte Imbalances, and Acid–Base Disorders This Photo by Unknown Author...

Restricted and Non- Sensitive Drugs for Fluid and Electrolyte Imbalances, and Acid–Base Disorders This Photo by Unknown Author is licensed under CC Restricted and Non- Sensitive Learning outcomes 1. Describe conditions for which intravenous fluid therapy is indicated. 2. Explain the pharmacotherapy of sodium and potassium replacement therapy. 3. Discuss common causes of acidosis and alkalosis and the medications used to treat these conditions. 4. Describe the nurse’s role in the pharmacologic management of fluid balance, electrolyte, and acid-base disorders Restricted and Non- Sensitive Case study Sandy, a 16-year-old student, is brought to the clinic by her mother, who says that Sandy has been on ‘some sort of fad diet’. The mother is concerned because Sandy is weak and tired. During the nurse’s assessment, Sandy admits that she has been using laxatives and eating very little during the past few weeks. Her sodium level is 136 mEq/L, and potassium level is 2.8 mEq/L. What electrolyte imbalance is Sandy experiencing? How can it be corrected? Restricted and Non- Sensitive Fluid Balance This Photo by Unknown Author is licensed under CC Restricted and Non- Sensitive Body Fluid Compartments Water is responsible for about 60% of the total body weight in a middle-age adult Continuous exchange of fluids across semipermeable membranes between intracellular and extracellular fluid compartments Large molecules and those that are ionized less able to cross membranes Restricted and Non- Sensitive Major Fluid Compartments in the Body Restricted and Non- Sensitive Control of Water Balance Essential for homeostasis Frequent indications for IV therapy include imbalances of Body fluids Electrolytes Acid–base Restricted and Non- Sensitive Osmolality A measure of the number of dissolved solutes in 1 kg (1 L) of fluid Usually sodium, glucose, or urea Normal osmolality is 275–295 mOsm/kg Changes in osmolality can cause water to move to different compartments Greatest contributor is sodium Sodium controlled by hormone aldosterone Restricted and Non- Sensitive Tonicity The ability of a solution to cause a change in water movement across a membrane due to osmotic forces Tonicity of the plasma is used as a reference point when administering IV solutions Restricted and Non- Sensitive Osmosis Movement of water from area of low osmolality to areas of high osmolality Hypertonic intravenous fluid Water moves from interstitial space to plasma Hypotonic intravenous fluid Water moves from plasma to interstitial space Isotonic intravenous fluid No fluid shift Restricted and Non- Sensitive Movement of Fluids and Solution Tonicity Restricted and Non- Sensitive Regulation of fluid intake & output Achieved through complex mechanisms Most important regulator of fluid intake is thirst mechanism Primary regulators of fluid output: kidneys Renin–angiotensin-aldosterone system Antidiuretic hormone (ADH) Restricted and Non- Sensitive Fluid Balance Disorders Deficient fluid balance disorders Can cause dehydration or shock Treated with oral or intravenous fluids Excess fluid balance disorders Treated with diuretics The goal is to diagnose and correct the cause of the disorder Restricted and Non- Sensitive Fluid Replacement Agents Net loss of fluid from the body  dehydration & shock IV fluid therapy to maintain blood volume and support blood pressure Restricted and Non- Sensitive Intravenous Fluid Therapy Replaces fluids and electrolytes Uses crystalloids and colloids Causes of water and electrolyte loss Loss of GI fluids due to vomiting, diarrhea, chronic laxative use or GI suctioning Excessive sweating during hot weather, athletic activities or prolonged fever Sever burns, Haemorrhage Excessive diuresis due to diuretic therapy or uncontrolled diabetic ketoacidosis Restricted and Non- Sensitive Types of IV replacement fluid Crystalloids Colloids Restricted and Non- Sensitive Crystalloids IV solutions with electrolytes Closely mimic the body’s ECF Used to replace depleted fluids and promote urine output Capable of leaving plasma and moving to interstitial spaces and intracellular fluid Compartment entered depends on tonicity of intravenous fluid Restricted and Non- Sensitive Selected Crystalloid IV Solutions Drug Tonicity Normal saline(0.9% 0.9%NaCl) NACL Isotonic (3% Hypertonic saline 3%NaCl) NACL Hypertonic (0.45% Hypotonic saline NaCl) 0.45% NACL Hypotonic Lactated Ringer’s Isotonic Plasma-Lyte 148 Isotonic Plasma-Lyte 56 Hypotonic Dextrose Solutions Blank (D5DW) 5% dextrose in water sub 5 W Isotonic 5% dextrose in normal saline Hypertonic 5% dextrose in 0.2% normal saline Isotonic 5% dextrose in lactated Ringer’s Hypertonic 5% dextrose in Plasma-Lyte 56 Hypertonic Note: Because dextrose is metabolized quickly, the solution is sometimes considered hypotonic. Restricted and Non- Sensitive Isotonic crystalloids Expand the plasma volume without major fluid shifts between compartments Indications Treatment of fluid loss due to vomiting, diarrhoea or surgical procedures especially when there is low BP Normal saline is used Restricted and Non- Sensitive Hypertonic crystalloids Expand the plasma volume by drawing water from the cells and tissue Indications To relieve cellular oedema especially cerebral oedema Restricted and Non- Sensitive Hypotonic crystalloids Cause water to move out of plasma to the cells and tissues Not for plasma volume expansion Indications Treatment of hypernatremia and cellular dehydration Restricted and Non- Sensitive Adverse effects of crystalloids Isotonic and hypertonic solutions Excessive expansion of intravascular compartment and can cause fluid overload Hypotonic solutions Depletion of the intravascular compartment and can cause hypotension Too much expansion of intracellular compartment andcan cause peripheral oedema Restricted and Non- Sensitive Colloids Proteins, starches or other large molecules Molecules too large to easily cross capillary membrane Stay in intravascular space Rapidly expand plasma volume Draw water from intracellular fluid and interstitial spaces into plasma Increase osmotic pressure Used in the treating hypovolemic shock due to burns, hameorrhage or surgery Restricted and Non- Sensitive Selected Colloid Solutions (Plasma Volume Expanders) Drug Tonicity 5% albumin Isotonic Dextran 40 in normal Isotonic saline (D W) 5 Dextran 40 in Isotonic Dextran 70 in normal Isotonic saline Hetastarch 6% in normal Isotonic saline Plasma protein fraction Isotonic Restricted and Non- Sensitive Selected colloid solutions Normal serum albumin The most commonly used colloid Dextran ( a synthetic polysaccharide) infusions can double the plasma volume in within few minutes Hetastarch A synthetic colloid similar to 5% albumin with extended duration of action Restricted and Non- Sensitive Adverse effects of colloids Usually, safe May cause altered coagulation, resulting in bleeding Have no clotting factors or oxygen- carrying capacity Rarely, dextran therapy causes anaphylaxis or renal failure Restricted and Non- Sensitive Blood Products Only class of fluids that are able to carry oxygen Increase tissue oxygenation Increase plasma volume Most expensive and least available fluid because they require human donors Restricted and Non- Sensitive Indications for Blood Products Cryoprecipitate and plasma protein factors (PPF) Management of acute bleeding (greater than 50% slow blood loss or 20% acutely) Fresh frozen plasma (FFP) Increase clotting factor levels in patients with demonstrated deficiency Restricted and Non- Sensitive Indications for Blood Products (Contd.) Packed red blood cells (PRBCs) To increase oxygen-carrying capacity in patients with anemia, in patients with substantial hemoglobin deficits, and in patients who have lost up to 25% of their total blood volume Whole blood Same as for PRBCs, except that whole blood is more beneficial in cases of extreme (greater than 25%) loss of blood volume because whole blood also contains plasma Contains plasma proteins, which help draw fluid back into blood vessels from surrounding tissues Restricted and Non- Sensitive Adverse effects of Blood Products Incompatibility with recipient’s immune system Crossmatch testing Transfusion reaction Anaphylaxis Transmission of pathogens to recipient (hepatitis, HIV) Restricted and Non- Sensitive Electrolyte Balance This Photo by Unknown Author is licensed under CC BY-NC Restricted and Non- Sensitive Electrolytes Positively or negatively charged inorganic molecules Essential to Nerve conduction membrane permeability Water balance other critical body functions Restricted and Non- Sensitive Electrolytes Important to Human Physiology Compound Formula Cation Anion Calcium chloride CaCl C A C2 L 2 C Ca A 22+plus 2 C2Cl- L minus Disodium N Na A 2 HPO HPO4 2Na 2N + A plus HPO 2- 2 4 4 H P O sub 4, super 2 phosphate minus KCl K+ Cl- Potassium KCL K plus C L minus NaHCO3 Na + HPO3 - chloride NaCl HCl - NAHCO3 Na + PO3 Sodium N A plus bicarbonate Na2SO4 2Na+ SO4 2- Sodium chloride NACL N A plus C L minus Sodium sulfate NA2SO4 2 N A plus S O sub 4, super 2 minus Restricted and Non- Sensitive Electrolyte imbalance A sign of an underlying medical condition Associated with many disorders such as Renal impairment (the most common) Adverse effects of drugs (e.g. loop diuretics such as furosemide Therapeutic goal 1. Correct the electrolyte imbalance 2. Diagnose and treat the underlying cause Restricted and Non- Sensitive Electrolyte Imbalances Ion Condition Abnormal Serum Supportive Treatment* Value (mEq/L) Calcium Hypercalcemia Greater than 11 Hypotonic fluids or calcitonin Hypocalcemia Less than 4 Calcium supplements or vitamin D Chloride Hyperchloremia Greater than 112 Hypotonic fluid Hypochloremia Less than 95 Hypertonic salt solution Magnesium Hypermagnesemi Greater than 4 Hypotonic fluid a Less than 0.8 Magnesium supplements Hypomagnesemia Phosphate Hyperphosphatem Greater than 6 Dietary phosphate restriction ia Less than 1 Phosphate supplements Hypophosphatemi a Potassium Hyperkalemia Greater than 5 Hypotonic fluid, buffers, or dietary potassium Hypokalemia Less than 3.5 restriction Potassium supplements Sodium Hypernatremia Greater than 145 Hypotonic fluid or dietary sodium restriction Hyponatremia Less than 135 Hypertonic salt solution or sodium supplement *For all electrolyte imbalances, the primary therapeutic goal is to identify and correct the cause of the imbalance. Restricted and Non- Sensitive Sodium A major electrolyte in extracellular fluid Essential for maintaining osmolality, water balance, acid–base balance Water travels with or toward sodium Sodium movement is link between water retention, blood volume, and blood pressure Regulated by kidneys and aldosterone Restricted and Non- Sensitive Renal Regulation of Sodium and Potassium Balance Restricted and Non- Sensitive Hypernatremia Definition: Serum sodium level >145mEq/L Causes 1. Renal diseases (the most common) 2. ↑intake from dietary consumption or overtreatment with IV fluids containing NaCl or NaHCO3 3. High net water losses from inadequate water intake, watery diarrhoea, fever, burns 4. High doses of corticosteroids Restricted and Non- Sensitive Hypernatremia (Contd.) Pathophysiology ↑ serum Na  ↑ osmolality of the plasma  draw fluid from the interstitial space and cells  ↑ cellular dehydration Clinical features o Thirst o Fatigue, weakness o muscle twitching o Convulsions, altered mental status, decreased level of consciousness Restricted and Non- Sensitive Hypernatremia (Contd.) o Management A low-salt diet for mild hypernatremia Acute hypernatremia IV infusion of hypotonic fluids such as 5% dextrose or 0.45% NaCl if the patient is hypovolemic Diuretics if the patient is hypervolemic Restricted and Non- Sensitive Hyponatremia Definition: Serum sodium level < 135mEq/L Causes 1. ↑sodium loss from the kidneys (diuretic use and advanced kidney disease) GIT (vomiting, diarrhoea, suctioning) Skin (burns, excessive sweating or prolonged fever) 2. Excessive dilution of the plasma Excessive ADH secretion IV infusion of hypotonic solution Restricted and Non- Sensitive Hyponatremia (Contd.) Clinical features Early symptoms Nausea, vomiting, anorexia, abdominal cramping Later signs Altered neurologic function such as confusion, lethargy, convulsions, coma, muscle twitching, tremors Restricted and Non- Sensitive Hyponatremia (Contd.) o Management Hyponatremia caused by excessive dilution loop diuretics to cause an isotonic diuresis Hyponatremia caused by sodium loss oral sodium chloride or intravenous fluids containing salt Normal saline Lactated Ringer's Restricted and Non- Sensitive Potassium Balance Most abundant intracellular cation Essential for proper nerve and muscle function Maintaining acid–base balance Influenced by aldosterone For each sodium ion reabsorbed, one potassium ion secreted into renal tubules Imbalances can be serious, even fatal from dysrhythmias Restricted and Non- Sensitive Hyperkalemia Definition: Serum potassium level > 5mEq/L Causes 1. Renal diseases (the most common) 2. ↑intake from dietary consumption especially while patients on potassium sparing diuretics Restricted and Non- Sensitive Hyperkalemia (Contd.) Clinical features Most serious are dysrhythmias and heart block Other symptoms muscle twitching, fatigue, paresthesia, dyspnea, cramping, and diarrhea Restricted and Non- Sensitive Hyperkalemia (Contd.) o Management Mild cases Restrict dietary sources e.g., bananas, citrus & dried fruits If a patient is taking a potassium-sparing diuretics, lower the dose or substitute with a thiazide or loop diuretics Severe cases Administer IV glucose and insulin Administer albuterol nebulizer Administer calcium gluconate to counteract potassium toxicity on heart Restricted and Non- Sensitive Hypokalemia Definition: Serum potassium level < 3.5mEq/L Causes 1. High doses of loop diuretics 2. Strenuous muscle activity 3. Severe vomiting or diarrhea Restricted and Non- Sensitive Hypokalemia (Contd.) Clinical features Neurons and muscles are most sensitive to K loss Muscle weakness, lethargy, anorexia, dysrhythmias, cardiac arrest Restricted and Non- Sensitive Hypokalemia (Contd.) o Management Mild hypokalemia Increase dietary intake e.g., dried fruits, nuts, avocados Severe hypokalemia oral or parenteral potassium supplements Liquid preparation must be diluted with water or fruit juices Restricted and Non- Sensitive Acid-Base Disorders This Photo by Unknown Author is licensed under CC BY-NC-ND Restricted and Non- Sensitive Alkalosis and Acidosis Acidosis is excess acid (pH below 7.35) Alkalosis is excess base (pH above 7.45) Symptoms of underlying disorder May be fatal if not treated rapidly Treatment of underlying cause is the uttermost important Restricted and Non- Sensitive Regulation of acid-base balances Buffers Chemicals help to maintain normal body pH by neutralizing strong acids and bases Bicarbonates and phosphate ions Two mechanisms to remove acid 1. Removal of CO2 through the lungs 2. Removal of H+ ions through the kidneys Restricted and Non- Sensitive Acid–base imbalances Restricted and Non- Sensitive Causes of Alkalosis and Acidosis Acidosis Alkalosis Respiratory Origins of Acidosis Respiratory Origins of Alkalosis Hypoventilation or shallow breathing Hyperventilation due to asthma, anxiety, or high altitude Airway constriction Damage to respiratory center in medulla Metabolic Origins of Acidosis Metabolic Origins of Alkalosis Severe diarrhea Constipation for prolonged periods Kidney failure Ingestion of excess sodium bicarbonate Diabetes mellitus Diuretics that cause potassium depletion Excess alcohol ingestion Severe vomiting Starvation Restricted and Non- Sensitive Pharmacotherapy of Acidosis Symptoms affect central nervous system depression Lethargy, confusion, coma Deep, rapid respirations in attempt to blow off excess acid (Kussmaul breathing) in metabolic acidosis Watch this video https://www.youtube.com/watch?v=TG0vpKa e3Js Treatment of metabolic acidosis to quickly reverse effects of excess acid in blood Administration of sodium bicarbonate infusion Restricted and Non- Sensitive Pharmacotherapy of Alkalosis Symptoms are due to central nervous system stimulation Nervousness, hyperactive reflexes, convulsions Slow, shallow respirations in attempt to retain acid in metabolic alkalosis Treatment Administration of sodium chloride with potassium chloride (mild cases) Administration of ammonium chloride (severe cases) Restricted and Non- Sensitive Nursing implications Restricted and Non- Sensitive Nursing Implications (Assessment) Assess baseline fluid volume and electrolyte status Assess baseline vital signs Assess skin, mucous membranes, daily weights, I&O Before giving potassium, assess ECG Assess for contraindications to therapy Assess transfusion history Establish venous access as needed Restricted and Non- Sensitive Nursing Implications (Monitor) Monitor serum electrolyte levels during therapy Monitor infusion rate, appearance of fluid or solution, infusion site Observe for infiltration, other complications of IV therapy Monitor for therapeutic response Normal lab values RBCs, WBC, H&H, electrolyte levels Improved fluid volume status Increased tolerance to activities Monitor for adverse effects Restricted and Non- Sensitive Nursing Implications (Fluid replacement) Administer colloids slowly Monitor for fluid overload and possible heart failure For blood products, follow administration procedures closely Monitor closely for signs of transfusion reactions Restricted and Non- Sensitive Nursing implication (Sodium Replacement Therapy) Assess sodium and electrolyte balance Be alert for signs of hyponatremia or hypernatremia Monitor serum sodium levels, urine specific gravity, serum and urine osmolarity Teach patient To report symptoms that may relate to fluid overload To drink water or balanced sports drinks to replenish lost fluids and electrolytes Restricted and Non- Sensitive Nursing Implications (Potassium infusion) IV potassium must not be given at a rate faster than 10 mEq/hr to patients who are not on cardiac monitors. For critically ill patients on cardiac monitors, rates of 20 mEq/hr or more may be used. NEVER give as an IV bolus or undiluted Restricted and Non- Sensitive Nursing Implications (Oral potassium) Must be diluted in water or fruit juice to minimize GI distress or irritation Monitor for complaints of nausea, vomiting, GI pain, or GI bleeding Restricted and Non- Sensitive Nursing implications (Acid-Base agents) Monitor arterial blood gas reports Sodium bicarbonate therapy Use cautiously in patients with cardiac disease or renal impairment Ammonium chloride therapy Contraindicated in presence of liver disease Infuse slowly to avoid ammonium toxicity and decrease irritation to veins Restricted and Non- Sensitive Case study (Refer to the recorded lecture for the answers) Sandy, a 16-year-old student, is brought to the clinic by her mother, who says that Sandy has been on ‘some sort of fad diet’. The mother is concerned because Sandy is weak and tired. During the nurse’s assessment, Sandy admits that she has been using laxatives and eating very little during the past few weeks. Her sodium level is 136 mEq/L, and potassium level is 2.8 mEq/L. What electrolyte imbalance is Sandy experiencing? How can it be corrected? Restricted and Non- Sensitive Key Terms Dehydration Shock Intravenous fluid therapy Crystalloids Colloids Hypernatraemia Hyponatraemia Hyperkalaemia Hypokalaemia Acidosis Alkalosis Restricted and Non- Sensitive Review Question 1. After studying this lesson, students should answer three multiple choice questions. 2. Scan the QR code or use the link to get access to the question. Link : https://forms.office.com/r/xEAus7eHmn Restricted and Non- Sensitive References 1. Adams & Michael (2017), Pharmacology for nurses: a pathophysiologic approach, 5th Edition 2. Lilley & Lane (2014), Pharmacology and the nursing process, 7th Edition