Cardiovascular III PDF

Cardiovascular III Chapters 25, 29, 54 Chapter 25 Antidysrhythmic Drugs Copyright © 2020 Elsevier Inc. All Rights Reserved. Antidysrhythmics  Dysrhythmia  Any deviation from the normal rhythm of the heart  Arrhythmia  “No rhythm” which implies asystole  Terms dysrhythmia and arrhythmia are use...

Cardiovascular III Chapters 25, 29, 54 Chapter 25 Antidysrhythmic Drugs Copyright © 2020 Elsevier Inc. All Rights Reserved. Antidysrhythmics  Dysrhythmia  Any deviation from the normal rhythm of the heart  Arrhythmia  “No rhythm” which implies asystole  Terms dysrhythmia and arrhythmia are used interchangeably with the term arrhythmia being most commonly used.  Antidysrhythmics  Used for:_____________________________________________________ Copyright © 2020 Elsevier Inc. All Rights Reserved. 3 Dysrhythmia  Can develop in association with many conditions After MI, cardiac surgery, or as a result of CAD  Usually serious and may require treatment with antidysrhythmic drug or nonpharmacological therapies  Disturbances of cardiac rhythm are the result of: __________________________________________. Copyright © 2020 Elsevier Inc. All Rights Reserved. 4 Cardiac Cell  Inside the resting cardiac cell, there is a net negative charge relative to the outside of the cell.  This difference in electronegative charge exists in all cardiac cells and is called the resting membrane potential (RMP) Copyright © 2020 Elsevier Inc. All Rights Reserved. 5 Resting Membrane Potential  An energy-requiring pump is needed to maintain this uneven distribution of ions. Sodium-potassium ATPase pump  The RMP results from an uneven distribution of ions (sodium, potassium, calcium) across the cell membrane. This is called Polarization Copyright © 2020 Elsevier Inc. All Rights Reserved. 6 Action Potential  A change in the distribution of ions causes cardiac cells to become excited.  The movement of ions across the cardiac cell’s membrane results in an electrical impulse spreading across the cardiac cells.  This electrical impulse leads to _____________ of the myocardial muscle. Copyright © 2020 Elsevier Inc. All Rights Reserved. 7 Action Potential (Cont.)  Five phases  Phase 0: upstroke Resting cardiac cell membrane suddenly becomes highly permeable to sodium ions; movement through sodium channels Depolarization (temporary equalization of pos. and neg. charges)  Phase 1 Begins a rapid process of repolarization that continues through Phases 2 and 3 to Phase 4, which is the RMP Copyright © 2020 Elsevier Inc. All Rights Reserved. 8 Action Potential Duration  Interval between Phase 0 and Phase 4  Absolute or effective refractory period—cardiac cell cannot be restimulated  Relative refractory period—the cardiac cell could be depolarized again if it received a powerful enough impulse (by a medication or pacemaker).  Threshold potential—a certain critical voltage which causes depolarization.  Automaticity or pacemaker activity—spontaneous depolarization. It is normal when it occurs in the SA node. Otherwise, dysrhythmias can occur. Copyright © 2020 Elsevier Inc. All Rights Reserved. 9 Aspects of Action Potential  SA node, AV node, and His-Purkinje cells all possess the property of automaticity.  SA node is the natural pacemaker of the heart.  SA node has an intrinsic rate of ___ to ___ bpm.  AV node has an intrinsic rate of ___ to ___bpm.  Ventricular Purkinje fibers have an intrinsic rate of ___ or fewer beats per minute. Copyright © 2020 Elsevier Inc. All Rights Reserved. 10 Electrocardiography  ECG or EKG  P wave  PR interval  QRS complex  ST segment  T wave Copyright © 2020 Elsevier Inc. All Rights Reserved. 11 Common Dysrhythmias  Supraventricular dysrhythmias  Originate above the ventricles in SA or AV node or atrial myocardium  Ventricular dysrhythmias  Originate below the AV node in the His-Purkinje system or ventricular myocardium  Ectopic foci  Outside the conduction system  Conduction blocks  Dysrhythmias that involve the disruption of impulse conduction between the atria and ventricles Copyright © 2020 Elsevier Inc. All Rights Reserved. 12 Common Dysrhythmias (Cont.)  Atrial fibrillation  AV nodal reentrant tachycardia (AVNRT)—gives rise to:  Paroxysmal (sudden) supraventricular tachycardia (PSVT)  Varying degrees of AV block (1st, 2nd, 3rd degree)  Premature ventricular contractions (PVC)  Ventricular fibrillation  Ventricular tachycardia Copyright © 2020 Elsevier Inc. All Rights Reserved. 13 Antidysrhythmic Drugs  Categorized according to where and how they affect cardiac cells  Vaughan Williams classification System commonly used to classify antidysrhythmic drugs Based on the electrophysiologic effect of particular drugs on the action potential Copyright © 2020 Elsevier Inc. All Rights Reserved. 14 Vaughan Williams Classification: Mechanism of Action and Indications  Class I—Sodium channel blockers  Class Ia  Class Ib  Class Ic  Class II—Beta blockers  Class III—Drugs that increase action potential duration (Amiodarone)  Class IV—Calcium channel blockers Copyright © 2020 Elsevier Inc. All Rights Reserved. 15 Vaughan Williams Classification: Mechanism of Action and Indications (Cont.)  Class Ia: procainamide, quinidine, and disopyramide Block sodium (fast) channels Delay repolarization Increase APD (action potential duration) Used for atrial fibrillation, premature atrial contractions, premature ventricular contractions, ventricular tachycardia, WolffParkinson-White syndrome Copyright © 2020 Elsevier Inc. All Rights Reserved. 16 Vaughan Williams Classification: Mechanism of Action and Indications (Cont.)  Class Ib: phenytoin, lidocaine  Block sodium channels  Accelerate repolarization  Increase or decrease APD  Lidocaine is used for ventricular dysrhythmias only.  Phenytoin is used for atrial and ventricular tachydysrhythmias caused by digitalis toxicity or long QT syndrome. Copyright © 2020 Elsevier Inc. All Rights Reserved. 17 Vaughan Williams Classification: Mechanism of Action and Indications (Cont.) Class Ic: flecainide, propafenone  Block sodium channels (more pronounced effect)  Little effect on APD or repolarization  Used for severe ventricular dysrhythmias  May be used in atrial fibrillation or flutter, WolffParkinson-White syndrome, supraventricular tachycardia dysrhythmias Copyright © 2020 Elsevier Inc. All Rights Reserved. 18 Vaughan Williams Classification: Mechanism of Action and Indications (Cont.)  Class II: beta blockers Reduce or block sympathetic nervous system stimulation, thus reducing transmission of impulses in the heart’s conduction system (slows heart rate) Depress Phase 4 depolarization General myocardial depressants for both supraventricular and ventricular dysrhythmias Also used as antianginal and antihypertensive drugs Copyright © 2020 Elsevier Inc. All Rights Reserved. 19 Vaughan Williams Classification: Mechanism of Action and Indications (Cont.)  Class III: amiodarone, dronedarone, dofetilide, sotalol, ibutilide Increase APD Prolong repolarization in Phase 3 Used for dysrhythmias that are difficult to treat Life-threatening ventricular tachycardia or fibrillation, atrial fibrillation or flutter that is resistant to other drugs Copyright © 2020 Elsevier Inc. All Rights Reserved. 20 Vaughan Williams Classification: Mechanism of Action and Indications (Cont.)  Class IV:  Calcium channel blockers Inhibit slow-channel (calcium-dependent) pathways  Depress Phase 4 depolarization  Reduce AV node conduction  Used for paroxysmal supraventricular tachycardia (PSVT); rate control for atrial fibrillation and flutter Copyright © 2020 Elsevier Inc. All Rights Reserved. 21 Contraindications to the Use of Antidysrhythmic Drugs Known drug allergy Second- or third-degree AV block, bundle branch block, cardiogenic shock, sick sinus syndrome, and any other ECG changes depending on the clinical judgment of a cardiologist. Other antidysrhythmic drugs Copyright © 2020 Elsevier Inc. All Rights Reserved. 22 Antidysrhythmics: Adverse Effects  ALL antidysrhythmics can cause ____________! Hypersensitivity reactions Nausea, vomiting, and diarrhea Dizziness Headache and blurred vision Prolongation of the QT interval Copyright © 2020 Elsevier Inc. All Rights Reserved. 23 Antidysrhythmics: Drug Interactions  warfarin: monitor international normalized ratio (INR)— Amiodarone can cause increase in bleeding time.  Grapefruit juice: amiodarone, disopyramide, and quinidine Copyright © 2020 Elsevier Inc. All Rights Reserved. 24 Procainamide (Pronestyl)  Class Ia  Uses: atrial and ventricular tachydysrhythmias  Significant adverse effects: include ventricular dysrhythmias, blood disorders, systemic lupus erythematosus (SLE)–like syndrome, nausea, vomiting, diarrhea, fever, leukopenia, maculopapular rash, flushing, and torsades de pointes (type of V-tach) resulting from prolongation of the QT interval  Contraindications: known hypersensitivity, heart block, and SLE Copyright © 2020 Elsevier Inc. All Rights Reserved. 25 Lidocaine (Xylocaine)  Class Ib  Action: raises the ventricular fibrillation threshold  Significant adverse effects: twitching, convulsions, confusion, respiratory depression or arrest, hypotension, bradycardia, and dysrhythmias  Contraindications: hypersensitive, severe SA or atrioventricular (AV) intraventricular block, or Stokes-Adams or Wolff-Parkinson-White syndrome Copyright © 2020 Elsevier Inc. All Rights Reserved. 26 Flecainide (Tambocor)  Class Ic  First-line drug in the treatment of atrial fibrillation  Negative inotropic effect and depresses left ventricular function  Adverse effects: dizziness, visual disturbances, and dyspnea  Contraindications: hypersensitivity, cardiogenic shock, second- or third-degree AV block, and non–life-threatening dysrhythmias Copyright © 2020 Elsevier Inc. All Rights Reserved. 27 Propafenone (Rythmol)  Class Ib  Similar action to flecainamide  Mild beta-blocking effects  Use: life-threatening ventricular dysrhythmias, atrial fibrillation  Most common reported adverse reaction: dizziness  Others: metallic taste, constipation, headache, nausea, and vomiting Copyright © 2020 Elsevier Inc. All Rights Reserved. 28 Atenolol (Tenormin)  Class II  Cardioselective beta blocker; preferentially blocks the beta1-adrenergic receptors that are located primarily in the heart.  Noncardioselective beta blockers block not only the beta1-adrenergic receptors in the heart but also the beta2-adrenergic receptors in the lungs and therefore can exacerbate pre-existing asthma or chronic obstructive pulmonary disease.  Uses: antidysrhythmic, hypertension, and _________  Contraindications: severe bradycardia, second- or third-degree heart block, heart failure, cardiogenic shock, or a known hypersensitivity Copyright © 2020 Elsevier Inc. All Rights Reserved. 29 Esmolol (Brevibloc)  Ultrashort-acting beta blocker  Cardioselective, blocks beta1-adrenergic receptors  Use: acute treatment of supraventricular tachydysrhythmias; hypertension; post-MI tachydysrhythmias Metoprolol (Lopressor) Class II Another cardioselective beta blocker commonly given after an MI to reduce risk of sudden cardiac death Treatment of hypertension and angina Copyright © 2020 Elsevier Inc. All Rights Reserved. 30 Amiodarone (Cordarone, Pacerone)  Class III  Prolongs the action potential duration and the effective refractory period in all cardiac tissues  Blocks both the alpha- and beta-adrenergic receptors of the sympathetic nervous system  Uses: one of the most effective antidysrhythmic drugs for controlling both supraventricular and ventricular dysrhythmias  Management of sustained ventricular tachycardia, ventricular fibrillation, and nonsustained ventricular tachycardia  Drug of choice for ventricular dysrhythmias according to the Advanced Cardiac Life Support guidelines  Adverse effects: corneal microdeposits, which may cause visual halos, photophobia, and dry eyes; photosensitivity; pulmonary toxicity Copyright © 2020 Elsevier Inc. All Rights Reserved. 31 Amiodarone (Cordarone, Pacerone) (Cont.)  Drug interactions: digoxin and warfarin  (Amiodarone may affect digoxin levels)  If taking Amiodarone and warfarin, may have unusual/excess bleeding  Contraindications: hypersensitivity, severe sinus bradycardia or second- or third-degree heart block Copyright © 2020 Elsevier Inc. All Rights Reserved. 32 Diltiazem (Cardizem, Others)  Class IV  Temporary control of a rapid ventricular response in patients with atrial fibrillation or flutter and PSVT  Contraindications: hypersensitivity, acute myocardial infarction, pulmonary congestion, Wolff-Parkinson-White syndrome, severe hypotension, cardiogenic shock, sick sinus syndrome, or second- or third-degree AV block Copyright © 2020 Elsevier Inc. All Rights Reserved. 33 Verapamil (Calan)  Class IV  Inhibits calcium ion influx across the slow calcium channels in cardiac conduction time Results in dramatic effects on the AV node  Used to prevent and convert recurrent PSVT and control ventricular response in atrial flutter or fibrillation  Other uses: treat angina, hypertension, and hypertrophic cardiomyopathy Copyright © 2020 Elsevier Inc. All Rights Reserved. 34 Unclassified Antidysrhythmic  Adenosine (Adenocard)  Slows conduction through the AV node  Used to convert PSVT to sinus rhythm  Very short half-life—less than ___________  Only administered as fast intravenous (IV) push  May cause asystole for a few seconds  Other adverse effects are minimal.  Teach patient: this medication will reduce your heart rate; may feel discomfort for a few seconds Copyright © 2020 Elsevier Inc. All Rights Reserved. 35 Nursing Implications—related to all Antidysrythmics  Obtain a thorough drug and medical history.  Measure baseline blood pressure (BP), pulse, input and output, and cardiac rhythm.  Measure serum potassium levels before initiating therapy.  Assess for conditions that may be contraindications for use of specific drugs.  Assess for potential drug interactions.  Instruct patients to report dosing schedules and adverse effects to physician. Copyright © 2020 Elsevier Inc. All Rights Reserved. 36 Nursing Implications (Cont.)  During therapy, monitor cardiac rhythm, heart rate, BP, general well-being, skin color, temperature, and heart and lung sounds.  Assess plasma drug levels as indicated.  Monitor for toxic effects. Copyright © 2020 Elsevier Inc. All Rights Reserved. 37 Nursing Implications  Instruct patients to take medications as scheduled and not to skip doses or double up for missed doses.  Instruct patients to contact their physicians for instructions if a dose is missed.  Instruct patients not to crush or chew oral sustainedrelease preparations.  Monitor ECG for prolonged QT interval with use of antidysrhythmics, including amiodarone, procainamide,  Administer IV infusions with an IV pump.  Solutions of lidocaine that contain epinephrine should not be given IV; they are to be used ONLY as local anesthetics. Copyright © 2020 Elsevier Inc. All Rights Reserved. 38 Nursing Implications (Cont.)  Ensure that the patient knows to notify health care provider of any worsening of dysrhythmia or toxic effects  Shortness of breath  Edema  Dizziness  Syncope  Chest pain  Gastrointestinal distress  Blurred vision Copyright © 2020 Elsevier Inc. All Rights Reserved. 39 Nursing Implications (Cont.)  Teach patients taking beta blockers, digoxin, and other drugs how to take their own radial pulse for 1 full minute  Teach patients to notify their physicians before taking the next dose if the pulse is less than 60 beats/min.  Monitor for therapeutic response:  Decreased BP in hypertensive patients  Decreased edema  Decreased fatigue  Regular pulse rate  Pulse rate without major irregularities  Improved regularity of rhythm  Improved cardiac output Copyright © 2020 Elsevier Inc. All Rights Reserved. 40 Small Group Activity  Develop a plan of care for your patient (see rhythm strip).  Focus on cardiac sequence of drugs used to eliminate the dysrhythmia and care for the patient post-dysrhythmia. Break Questions? Chapter 29 Fluids and Electrolytes Copyright © 2020 Elsevier Inc. All Rights Reserved. Overview  Fluid and electrolyte management is one of the cornerstones of patient care.  Affected by most disease processes, tissue injuries, and surgical procedures  Provide transportation of nutrients to cells and transports waste products away from cells Copyright © 2020 Elsevier Inc. All Rights Reserved. 44 Fluid Balance Total body water Composed of: Intracellular fluid (ICF)—2/3 of our fluid Extracellular fluid (ECF)—1/3 of our fluid  Interstitial fluid (ISF)—around the cells  Intravascular fluid (IVF)—inside vessels/circulatory system 60% of adult human body is water. Copyright © 2020 Elsevier Inc. All Rights Reserved. 45 Fluid Balance (Cont.) Plasma proteins (like albumin) exert constant osmotic pressure. Colloid oncotic pressure (COP)—pulls fluid toward it Normally 24 mm Hg ISF (interstitial fluid) exerts hydrostatic pressure. Normally 17 mm Hg Copyright © 2020 Elsevier Inc. All Rights Reserved. 46 Acid-Base Balance  Important bodily function  Regulated by respiratory system and kidney  Acid  Base  pH-7.35 to 7.45 Copyright © 2020 Elsevier Inc. All Rights Reserved. 47 Crystalloids Solutions containing fluids and electrolytes that are normally found in the body Maintains the osmotic gradient between extravascular and intravascular compartments Do not contain proteins (colloids) No risk for viral transmission, anaphylaxis, or alteration in coagulation profile Copyright © 2020 Elsevier Inc. All Rights Reserved. 48 Crystalloids (Cont.) Better for treating dehydration rather than expanding plasma volume Used as maintenance fluids to: Compensate for insensible fluid losses Replace fluids Manage specific fluid and electrolyte disturbances Promote urinary flow Question: what will vital signs look like with dehydration? Copyright © 2020 Elsevier Inc. All Rights Reserved. 49 Crystalloids (Cont.) Normal saline (NS; 0.9% sodium chloride) Half NS (0.45% sodium chloride) Hypertonic saline (3% sodium chloride) Lactated Ringer’s solution Dextrose 5% in water (D5W) Copyright © 2020 Elsevier Inc. All Rights Reserved. 50 Crystalloids (Cont.)  Indications include:  Acute liver failure  Acute nephrosis  Adult respiratory distress syndrome  Burns  Cardiopulmonary bypass  Hypoproteinemia  Renal dialysis  Reduction of the risk for deep vein thrombosis  Shock Copyright © 2020 Elsevier Inc. All Rights Reserved. 51 Crystalloids (Cont.) Adverse effects May cause edema, especially peripheral or pulmonary May dilute plasma proteins, reducing COP Effects may be short-lived. Prolonged infusions may worsen alkalosis or acidosis. Copyright © 2020 Elsevier Inc. All Rights Reserved. 52 Crystalloids: Sodium Chloride Concentrations 0.9%: physiologically normal concentration of sodium chloride (isotonic), and it is referred to as NS. 0.45% (“half-normal”)-hypotonic 0.25% (“quarter-normal”)-hypotonic 3% (hypertonic saline) 5% (hypertonic saline) Copyright © 2020 Elsevier Inc. All Rights Reserved. 53 Colloids Protein substances (like albumin and dextran) Increase COP (colloid oncotic pressure) Move fluid from interstitial compartment to plasma compartment in vessels (when plasma protein levels are low) Albumin 5% and 25% (from human donors) Dextran 40, 70, or 75 (a glucose solution) Hetastarch (synthetic, derived from cornstarch) Copyright © 2020 Elsevier Inc. All Rights Reserved. 54 Colloids: Indications Used to treat wide variety of conditions when patient requires plasma volume expansion Shock Burns Copyright © 2020 Elsevier Inc. All Rights Reserved. 55 Colloids: Adverse Effects Adverse effects 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. Copyright © 2020 Elsevier Inc. All Rights Reserved. 56 Colloids: Albumin Natural protein that is normally produced by the liver Responsible for generating approximately 70% of the COP Sterile solution of serum albumin that is prepared from pooled blood, plasma, serum, or placentas obtained from healthy human donors Pasteurized to destroy any contaminants Copyright © 2020 Elsevier Inc. All Rights Reserved. 57 Dextran Solution of glucose Actions similar to those of human albumin in that it expands the plasma volume by drawing fluid from the interstitial space to the intravascular space Contraindications: Hypersensitivity HF Renal insufficiency Extreme dehydration Copyright © 2020 Elsevier Inc. All Rights Reserved. 58 Blood Products Only class of fluids that are able to carry oxygen Increase tissue oxygenation Increase plasma volume (PV) Most expensive and least available fluid because they require human donors Copyright © 2020 Elsevier Inc. All Rights Reserved. 59 Blood Products (Cont.) Increase colloid osmotic pressure and PV Pull fluid from extravascular space into intravascular space (plasma expanders) Red blood cell products also carry _________. Increase body’s supply of various products (e.g., clotting factors, hemoglobin) Copyright © 2020 Elsevier Inc. All Rights Reserved. 60 Blood Products (Cont.) Use depends on the specific indication Indications—part 1  Cryoprecipitate and plasma protein factors 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 Copyright © 2020 Elsevier Inc. All Rights Reserved. 61 Blood Products (Cont.) Indications—part 2 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 Copyright © 2020 Elsevier Inc. All Rights Reserved. 62 Blood Products Adverse effects Incompatibility with recipient’s immune system Crossmatch testing Transfusion reaction Anaphylaxis Transmission of pathogens to recipient (hepatitis, human immunodeficiency virus) Copyright © 2020 Elsevier Inc. All Rights Reserved. 63 Physiology of Electrolyte Balance Work in conjunction with fluids to keep the body in balance Measured in milliequivalent (mEq) Positively charged cations Sodium, potassium, calcium, magnesium Negatively charged ions Chloride, phosphate, bicarbonate Copyright © 2020 Elsevier Inc. All Rights Reserved. 64 Electrolytes Principal extracellular fluids (ECF) electrolytes Sodium cations (Na+) Chloride anions (Cl−) Principal intracellular fluids (ICF) electrolyte Potassium (K+) Others Calcium, magnesium, phosphorus Copyright © 2020 Elsevier Inc. All Rights Reserved. 65 Control of Electrolytes Renin-angiotensin-aldosterone system Antidiuretic hormone system Sympathetic nervous system Copyright © 2020 Elsevier Inc. All Rights Reserved. 66 Potassium Most abundant positively charged electrolyte inside cells 95% of body’s potassium is intracellular. Potassium content outside of cells ranges from 3.5 to 5 mEq/L. Potassium levels are critical to normal body function. Copyright © 2020 Elsevier Inc. All Rights Reserved. 67 Potassium (Cont.) Potassium obtained from foods Fruit and fruit juices (bananas, oranges, apricots, dates, raisins, broccoli, green beans, potatoes, tomatoes), meats, fish, wheat bread, and legumes & kiwis Excess dietary potassium excreted via kidneys Impaired kidney function leads to higher serum levels, possibly toxicity. Hypokalemia: deficiency of potassium; serum potassium level less than _____ mEq/L Copyright © 2020 Elsevier Inc. All Rights Reserved. 68 Potassium (Cont.)  Excessive potassium loss (rather than poor dietary intake)        Alkalosis Corticosteroids Diarrhea Ketoacidosis Laxative misuse Hyperaldosteronism Increased secretion of mineralocorticoids Copyright © 2020 Elsevier Inc. All Rights Reserved.  Burns  Thiazide, thiazide-like, and _____ diuretics  Vomiting  Malabsorption  Others 69 Potassium (Cont.) Hypokalemia, in the presence of digoxin therapy, can cause ___________, resulting in serious ventricular dysrhythmias. Symptoms of hypokalemia: Constipation Heart palpitations Extreme tiredness (fatigue) Muscle weakness and spasms Tingling and numbness Copyright © 2020 Elsevier Inc. All Rights Reserved. 70 Potassium (Cont.) Hyperkalemia: excessive serum potassium; serum potassium level over _______mEq/L          Potassium supplements ACE inhibitors Renal failure Excessive loss from cells Potassium-sparing diuretics Burns Trauma Metabolic acidosis Infections Copyright © 2020 Elsevier Inc. All Rights Reserved. 71 Potassium (Cont.) Potassium is responsible for: Muscle contraction Transmission of nerve impulses Regulation of heartbeat Maintenance of acid-base balance Isotonicity Copyright © 2020 Elsevier Inc. All Rights Reserved. 72 Potassium Main indication Treatment or prevention of potassium depletion when dietary means are inadequate Other therapeutic uses Stop irregular heartbeats Management of tachydysrhythmias that can occur after cardiac surgery Copyright © 2020 Elsevier Inc. All Rights Reserved. 73 74 Potassium (Cont.) Adverse effects  Oral preparations Diarrhea, nausea, vomiting, GI bleeding, ulceration  IV administration Pain at injection site Phlebitis Rate of administration  Excessive administration Hyperkalemia Toxic effects Copyright © 2020 Elsevier Inc. All Rights Reserved. Potassium (Cont.) Hyperkalemia manifestations Muscle weakness, paresthesia, paralysis, cardiac rhythm irregularities (leading to possible ventricular fibrillation and cardiac arrest) Treatment of severe hyperkalemia IV sodium bicarbonate, calcium gluconate or calcium chloride, dextrose with insulin Sodium polystyrene sulfonate (Kayexalate) or hemodialysis to remove excess potassium Copyright © 2020 Elsevier Inc. All Rights Reserved. 75 Sodium Polystyrene Sulfonate (Potassium Exchange Resin)  Kayexalate  Cation exchange resin used to treat hyperkalemia  Oral, nasogastric tubal, or as enema  Works in intestine  Closely monitor electrolytes  Do not give to patient who do not have normal bowel function Copyright © 2020 Elsevier Inc. All Rights Reserved. 76 Patiromer (Veltassa)  New oral drug to treat hyperkalemia  Non-absorbed cation exchange polymer  Increases fecal potassium excretion  Delayed onset of action therefore not indicated for emergent, life-threatening hyperkalemia  Do not give within 6 hours of other oral meds  Adverse effects: hypomagnesemia, hypokalemia, constipation, diarrhea, nausea  Dilute and give with food Copyright © 2020 Elsevier Inc. All Rights Reserved. 77 Sodium Most abundant positively charged electrolyte outside cells Normal concentration outside cells is 135 to 145 mEq/L Maintained through dietary intake of sodium chloride Salt, fish, meats, foods flavored or preserved with salt Copyright © 2020 Elsevier Inc. All Rights Reserved. 78 Sodium (Cont.) Hyponatremia: sodium loss or deficiency; serum levels below 135 mEq/L  Symptoms Lethargy, stomach cramps, hypotension, vomiting, diarrhea, seizures  Causes Same causes as hypokalemia; prolonged diarrhea or vomiting, or renal disorders; diuretic use Copyright © 2020 Elsevier Inc. All Rights Reserved. 79 Sodium (Cont.) Hypernatremia: sodium excess; serum levels over 145 mEq/L  Symptoms Water retention (edema), hypertension Red, flushed skin; dry, sticky mucous membranes; increased thirst; elevated temperature; decreased urine output  Causes Poor renal excretion stemming from kidney malfunction; inadequate water consumption and dehydration Copyright © 2020 Elsevier Inc. All Rights Reserved. 80 Sodium (Cont.) Sodium is responsible for: Control of water distribution Fluid and electrolyte balance Osmotic pressure of body fluids Participation in acid-base balance Copyright © 2020 Elsevier Inc. All Rights Reserved. 81 Sodium (Cont.) Main indication Treatment or prevention of sodium depletion when dietary measures are inadequate Mild Treated with oral sodium chloride and/or fluid restriction Severe Treated with IV NS or lactated Ringer’s solution Copyright © 2020 Elsevier Inc. All Rights Reserved. 82 Sodium (Cont.) Adverse effects Oral administration Nausea, vomiting, cramps IV administration Venous phlebitis Copyright © 2020 Elsevier Inc. All Rights Reserved. 83 Nursing Implications  Assess baseline fluid volume and electrolyte status.  Assess baseline vital signs.  Assess skin, mucous membranes, daily weights, and input and output.  Before giving potassium, assess electrocardiogram.  Assess for contraindications to therapy.  Assess transfusion history.  Establish venous access as needed. Copyright © 2020 Elsevier Inc. All Rights Reserved. 84 Nursing Implications (Cont.) Monitor serum electrolyte levels during therapy. Monitor infusion rate, appearance of fluid or solution, and infusion site. Observe for infiltration and other complications of IV therapy. Copyright © 2020 Elsevier Inc. All Rights Reserved. 85 Nursing Implications (Cont.) Parenteral infusions of potassium must be monitored closely. IV potassium must not be given at a rate faster than 10 mEq/hour to patients who are not on cardiac monitors. For critically ill patients on cardiac monitors, rates of 20 mEq/hour or more may be used. Never give as an IV bolus or undiluted potassium Copyright © 2020 Elsevier Inc. All Rights Reserved. 86 Nursing Implications (Cont.) Oral forms of potassium Must be diluted in water or fruit juice to minimize GI distress or irritation Monitor for complaints of nausea, vomiting, GI pain, and GI bleeding Copyright © 2020 Elsevier Inc. All Rights Reserved. 87 Nursing Implications 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. Copyright © 2020 Elsevier Inc. All Rights Reserved. 88 Nursing Implications: Fluids and Electrolytes Monitor for therapeutic response. After transfusion of packed red blood cells: increase in O2 and cardiac output Normal lab values Red blood cells, white blood cells, electrolyte levels Improved fluid volume status Increased tolerance to activities Monitor for adverse effects. Copyright © 2020 Elsevier Inc. All Rights Reserved. 89 Activity Break Questions? Chapter 54 Anemia Drugs Copyright © 2020 Elsevier Inc. All Rights Reserved. Hematopoiesis Formation of new blood cells Red blood cells (RBCs) Erythropoiesis White blood cells (WBCs) Platelets Copyright © 2020 Elsevier Inc. All Rights Reserved. 93 Hematopoiesis (Cont.) RBCs Manufactured in bone marrow Immature RBCs are reticulocytes. Lifespan is 120 days. More than one third of an RBC is made of hemoglobin. Heme: red pigment, contains iron Globin: protein chain Copyright © 2020 Elsevier Inc. All Rights Reserved. 94 Anemias  1. Maturation defects Cytoplasmic Nuclear  2. Excessive destruction of RBCs (hemolytic anemias) Intrinsic RBC abnormalities Extrinsic mechanisms  Underlying causes of anemia are red blood cell (RBC) maturation defects and factors secondary to excessive RBC destruction. Copyright © 2020 Elsevier Inc. All Rights Reserved. 95 Erythropoiesis-Stimulating Agents  Epoetin alfa (Epogen)  Biosynthetic form of the natural hormone erythropoietin  Used for treatment of anemia associated with endstage renal disease, chemotherapy-induced anemia, and anemia associated with zidovudine therapy  Medication is ineffective without adequate body iron stores and bone marrow function.  Most patients receiving epoetin alfa need to also receive an oral or intravenous (IV) iron preparation. Copyright © 2020 Elsevier Inc. All Rights Reserved. 96 Erythropoiesis-Stimulating Agents  Epoetin alfa (Epogen) Longer acting form of epoetin called darbepoetin (Aranesp) Contraindications: drug allergy, uncontrolled hypertension, hemoglobin levels are above 10 g/dL for cancer patients and 11 g/dL for renal patients, head and neck cancers, risk of thrombosis. Most frequent adverse effects: hypertension, fever, headache, pruritus, rash, nausea, vomiting, arthralgia, and injection site reaction 97 Iron Essential mineral in the body Oxygen carrier in hemoglobin and myoglobin Stored in the liver, spleen, and bone marrow Iron deficiency results in anemia. Copyright © 2020 Elsevier Inc. All Rights Reserved. 98 Iron Dietary sources: __________, __________and _______ Dietary iron must be converted by gastric juices before it can be absorbed. Copyright © 2020 Elsevier Inc. All Rights Reserved. 99 Iron (Cont.)  Some foods enhance iron absorption:  Orange juice  Veal  Fish  Ascorbic acid  Some foods impair iron absorption:  Eggs*  Corn  Beans*  Cereal products containing phytates * Also common dietary sources of iron. Copyright © 2020 Elsevier Inc. All Rights Reserved. 100 Iron (Cont.) Oral supplemental iron may be given as a single drug or as part of a multivitamin preparation. Parenteral Iron dextran (INFeD) Iron sucrose (Venofer) Ferric gluconate (Ferrlecit, Nulecit) Ferumoxytol (Feraheme) Copyright © 2020 Elsevier Inc. All Rights Reserved. 101 Iron: Indications Prevention and treatment of iron-deficiency syndromes Administration of iron alleviates the symptoms of iron-deficiency anemia, but the underlying cause of the anemia should be corrected. Copyright © 2020 Elsevier Inc. All Rights Reserved. 102 Iron: Adverse Effects Most common cause of pediatric poisoning deaths Causes nausea, vomiting, diarrhea, constipation, and stomach cramps and pain Causes black, tarry stools Liquid oral preparations may stain teeth. Injectable forms cause pain upon injection. Copyright © 2020 Elsevier Inc. All Rights Reserved. 103 Ferrous Sulfate 104 Most frequently used oral iron 300 mg BID or TID for adults Each tablet contains 65 mg of elemental iron. Copyright © 2020 Elsevier Inc. All Rights Reserved. Parenteral Iron 105 Iron dextran (INFeD, Dexferrum) May cause anaphylactic reactions, including major orthostatic hypotension A test dose of 25 mg of iron dextran is administered before injection of the full dose, and then the remainder of dose is given after 1 hour. Used less frequently now; replaced by newer products ferric gluconate and iron sucrose Copyright © 2020 Elsevier Inc. All Rights Reserved. Folic Acid (Folate) Water-soluble, B-complex vitamin Essential for erythropoiesis Primary uses Folic acid deficiency During pregnancy to prevent neural tube defects Malabsorption syndromes are the most common causes of deficiency. Copyright © 2020 Elsevier Inc. All Rights Reserved. 106 Folic Acid (Cont.) Should not be used until actual cause of anemia is determined May mask symptoms of pernicious anemia, which requires treatment other than folic acid Untreated pernicious anemia progresses to neurologic damage. 107 Copyright © 2020 Elsevier Inc. All Rights Reserved. 108 Other Anemia Drugs: Cyanocobalamin (Vitamin B12)  Used to treat pernicious anemia and other megaloblastic anemias  Administered orally or intranasally to treat vitamin B12 deficiency  Usually administered by deep intramuscular injection Copyright © 2020 Elsevier Inc. All Rights Reserved. Nursing Implications  Assess patient history and medication history, including drug allergies.  Assess baseline laboratory values, especially hemoglobin, hematocrit, reticulocytes, and others.  Obtain nutritional assessment.  Oral forms of iron should be taken between meals for maximum absorption, but may be taken with meals if GI distress occurs.  Oral forms should be given with juice but not with milk or antacids. 109 Nursing Implications (Cont.) Patients should remain upright for 15 to 30 minutes after oral iron doses to avoid esophageal corrosion. Patients should be encouraged to eat foods high in iron and folic acid. Keep away from children because oral forms may look like candy. Copyright © 2020 Elsevier Inc. All Rights Reserved. 110 Nursing Implications (Cont.) For iron dextran, a small test dose should be given. After 1 hour, if no reaction, the remainder of the dose can be given. Administer deeply into a large muscle mass using the Z-track method. Copyright © 2020 Elsevier Inc. All Rights Reserved. 111 Nursing Implications (Cont.) Monitor for therapeutic responses: Improved nutritional status Increased weight, activity tolerance, well-being Absence of fatigue Monitor for adverse effects. Copyright © 2020 Elsevier Inc. All Rights Reserved. 112 Questions? Reach out with questions, meet with tutors, and use all resources available to you. Have a great week!