Drugs Affecting the Lower Respiratory System

Gas Exchange/Oxygenation: Lower Respiratory System Oxygen Transport: http://www.youtube.com/watch?v=WXOBJEXxNEo

Lower Respiratory Tract

Physiology The lower respiratory tract is almost sterile because of various defense mechanisms in the upper respiratory system. Protective mechanisms All the tubes in the lower airway contain goblet cells, which secrete mucus to entrap any particles. Microorganisms and other foreign bodies are removed from the air by tiny hair-like structures called cilia. Gas exchange, perfusion, and respiration Lung tissue receives its blood supply from the bronchial artery, which branches directly off the thoracic aorta. Ventilation The act of breathing is controlled by the central nervous system (CNS).

Lower Respiratory Disorders COPD – chronic obstructive pulmonary disorder Airway obstruction with increased resistance of airflow to lung tissues Four major lung disorders: Chronic bronchitis Bronchiectasis – irreversible damage to bronchioles Emphysema – irreversible damage to alveoli Asthma – reversible, common in childhood Restrictive pulmonary disease Decrease in total lung capacity from fluid accumulation or loss of elasticity of the lung Examples: Pulmonary edema Pulmonary Fibrosis, genetic e.g. Cystic Fibrosis Lung tumors Thoracic deformities (scoliosis) Thoracic muscular disorders e.g. Myasthenia Gravis

Pathophysiology Acute bronchitis is caused most frequently by viruses. Chronic bronchitis is long-standing, largely irreversible inflammation of the bronchial tree. Asthma is a disorder characterized by recurrent episodes of bronchospasm, bronchial muscle spasm that leads to narrowed or obstructed airways. Instructor Notes: Physiology The lower respiratory tract is virtually sterile because of the various defense mechanisms in the upper respiratory system. Protective mechanisms All the tubes in the lower airway contain goblet cells, which secrete mucus to entrap any particles. Microorganisms and other foreign bodies are removed from the air by tiny hair-like structures called cilia. Gas exchange, perfusion, and respiration Lung tissue receives its blood supply from the bronchial artery, which branches directly off the thoracic aorta. Ventilation The act of breathing is controlled by the central nervous system (CNS).

Pathophysiology (cont’d) Emphysema is an abnormal distention of the lungs with air characterized by loss or degeneration of elastic tissue, disappearance of capillary walls, and breakdown of the alveolar walls. Pneumonia is an inflammation of the lungs. It can be caused by bacterial or viral invasion of the tissue or by aspiration of foreign substances into the lower respiratory tract. Cystic fibrosis is a hereditary disease that affects the functioning of the body’s exocrine glands: the mucus-secreting and sweat glands.

Pathophysiology of Asthma Primary response is chronic inflammation from exposure to allergens or irritants. This leads to airway hyper-responsiveness and acute airflow limitations Inflammatory mediators cause early-phase response. Inflammatory mediators cause early-phase response. Vascular congestion Edema formation Production of thick, tenacious mucus Bronchial muscle spasm Thickening of airway walls

Pathophysiology of Allergic Asthma Asthma is triggered when an irritant cross-links antigen receptors on mast cells. Histamine and other inflammatory responses are triggered

Factors Causing Obstruction in Asthma Bronchioles become occluded by muscle spasms, swollen mucosa, and mucus in the lumen.

Clinical Manifestations of Asthma Unpredictable and variable Recurrent episodes of wheezing, breathlessness, cough, and tight chest May be abrupt or gradual Lasts minutes to hours Expiration may be prolonged. Inspiration-expiration ratio of 1:2-4 Bronchospasm, edema, and mucus in bronchioles narrow the airways. Air takes longer to move out.

Clinical Manifestations Signs of hypoxemia ↑ pulse and blood pressure Restlessness ↑ anxiety Inappropriate behavior Pulsus paradoxus (drop in systolic BP during inspiratory cycle >10 mm Hg)

Complications Life-threatening asthma pO2 levels drop Too short of breath (dyspneic) to speak Perspiring profusely Drowsy/confused Require hospital care and often admitted to ICU

Mucolytic Drugs Prototype drug: acetylcysteine (Mucomyst) Mucolytics break down mucus. The drugs can be administered by a nebulizer or by direct instillation into the trachea. Mucolytics usually are reserved for patients who have major difficulty mobilizing and coughing up secretions. Prototype drug: acetylcysteine (Mucomyst)

Acetylcysteine: Core Drug Knowledge Pharmacotherapeutics Used to liquefy the thick, tenacious secretions. Pharmacodynamics It splits disulfide bonds that are responsible for holding the mucous material together. Contraindications and precautions Hypersensitive Adverse effects Bronchospasm, bronchoconstriction, chest tightness, a burning feeling in the upper airway, and rhinorrhea Unpleasant (sulfur, rotten egg) smell with

Acetylcysteine: Planning and Interventions Maximizing therapeutic effects Administer an inhaled beta-agonist before administering acetylcysteine. Minimizing adverse effects Inform the patient that nebulization may produce an initially disagreeable odor, but that this odor is transient.

Bronchodilators Prototype drug: albuterol (Proventil, Ventolin) Bronchodilators are drugs used to dilate the airways. Inhalation is the most frequent method using metered-dose inhalers (MDIs) or dry-powder inhalers (DPIs). Beta-agonists (sympathomimetics) One of the actions of beta stimulation in the sympathetic nervous system is dilation of the bronchi and increased rate and depth of respiration. Prototype drug: albuterol (Proventil, Ventolin)

Metered Dose Inhalers

Nebulizers

Albuterol: Core Drug Knowledge Pharmacotherapeutics Bronchodilator in managing Chronic Airway Limitation disease and asthma Pharmacodynamics It selectively stimulates receptors of the smooth muscle in the lungs, the uterus, and the vasculature that supplies the skeletal muscle. Side effects Tachycardia, palpitations, anxiety, tremors, headache, insomnia, muscle cramps, and upset stomach.

Albuterol: Nursing Diagnoses and Outcomes Anxiety related to sympathomimetic effects of albuterol administration Ineffective Tissue Perfusion: Cardiopulmonary related to rebound bronchoconstriction caused by overuse of albuterol

Albuterol: Teaching, Assessment, and Evaluation Patient and family education Teach patients that inhaled albuterol is a “rescue drug.” Teach patients how to use an MDI. Explain the importance of limiting caffeine intake.

Anticholinergic Agents Inhaled anticholinergic drugs are considered first-line treatment for patients with Chronic Airway Limitation (CAL). Anticholinergic agents diminish the effect of acetylcholine. In the respiratory system, use of inhaled anticholinergic drugs stops bronchoconstriction. Prototype drug: ipratropium bromide (Atrovent)

Ipratropium Bromide: Core Drug Knowledge Pharmacotherapeutics Used for maintenance treatment of bronchospasm Pharmacodynamics Antagonizes the action of acetylcholine by blocking muscarinic cholinergic receptors Side effects Cough, hoarseness, throat irritation Adverse effects Paradoxic acute bronchospasm

Ipratropium Bromide: Nursing Concerns Risk for Injury (anaphylactic reactions) related to allergies to soybeans, legumes, or soya lecithin.

Ipratropium Bromide: Teaching, Assessment, and Evaluation Patient and family education Advise patients that ipratropium is used prophylactically (prevention). Remind patients that overuse of ipratropium may induce adverse effects.

Xanthine Derivatives Prototype drug: *theophylline (Theodur) The xanthine derivatives, including theophylline, aminophylline, and caffeine, come from a variety of naturally occurring sources. They are excellent bronchodilators but do not work as rapidly as beta-adrenergic agonist drugs. Prototype drug: *theophylline (Theodur) *Not on drug list

Theophylline: Core Drug Knowledge Pharmacotherapeutics Indicated for the symptomatic relief or prevention of bronchial asthma and reversal of bronchospasm Administered orally and on a routine basis for maintenance Pharmacodynamics It is believed that bronchodilation is caused by inhibition of phosphodiesterase. Adverse effects Adverse effects related to theophylline use are related directly to serum levels of the drug.

Theophylline: Nursing Concerns Disturbed Sensory Perception: CNS effects of irritability, insomnia, and dizziness. Ineffective Tissue Perfusion: Cardiopulmonary related to cardiac effects of the drug. Risk for Injury related to headache, GI effects, and CNS effects.

Anti-Inflammatory In addition to bronchodilators, anti- inflammatory agents are used to manage respiratory disorders, especially asthma. Inhaled glucocorticoid steroids Glucocorticoid steroids are the most effective anti-inflammatory drugs available for managing respiratory disorders. Inhaled corticosteroid (ICS) agents have become first-line treatment for persistent asthma. Prototype drug: fluticasone/salmeterol (Advair), beclomethasone (Q-var)

fluticasone/salmeterol: Core Drug Knowledge Pharmacotherapeutics Used to prevent bronchospasm Used for maintenance (routine – not PRN) Pharmacodynamics Inhibit the production of leukotrienes and prostaglandins through interference with arachidonic acid metabolism. Side/Adverse effects Sore throat, hoarseness, coughing, dry mouth, and pharyngeal and laryngeal fungal infections

fluticasone/salmeterol: Nursing Concerns Impaired Verbal Communication related to dysphonia and cough Risk for oral infection related to immunosuppression

fluticasone/salmeterol: Core Drug Knowledge Patient and family education Patient education is important for inhaled steroid therapy. Importance of daily use, regardless of the absence of symptoms Rinse mouth after use of fluticasone/salmeterol (Advair)

Leukotriene Receptor Antagonist Leukotrienes are inflammatory mediators that are powerful bronchoconstrictors and vasodilators. Leukotrienes have been identified as important mediators in the pathology and symptomatology of asthma. They are used for prevention of asthma attacks. Prototype drugs: *montelukast (Singulair) *Not on drug list

Montelukast : Core Drug Knowledge Pharmacotherapeutics Prophylaxis or treatment of chronic asthma Pharmacodynamics Blocks receptors for the leukotrienes bound to the amino acid cysteine Side/Adverse effects Headache, gastritis, pharyngitis, and rhinitis Numerous drug interactions

Montelukast : Teaching, Assessment, and Evaluation Patient and family education Explain that montelukast is used in maintenance therapy. Encourage patients to take nonnarcotic analgesics if headache occurs.

Challenge Question Acetylcysteine (Mucomyst) for respiratory use is administered by: A. Inhalation B. SC C. Oral D. IV Inhalation. Oral use is indicated for acetominophen overdose.

Challenge Question Albuterol is given for acute exacerbation of Chronic Airway Limitation (CAL) or asthma. A. True B. False

Challenge Question Patients using inhaled steroids are at a high risk for developing Oral bacterial infection Oral viral infection Oral fungal infection C. Oral fungal infection

Question Montelukast is used for A. Prophylaxis – prevention of attacks B. Acute attack C. Infection D. All of the above

Match Drug + Administration Routine PRN Ipratroprium (Atrovent) Fluticasone/ salmeterol (Advair) Albuterol (Proventil)

Homework Activity - 1: Orientation to Shadow Health Digital Clinical Experience (DCE) You will need to be in a private place or use head phones for this activity due to the audio/video component. CLASS PIN:  February2016-4444-1603-7874-2405 1. Log in and create an account. There is no cost to you for this activity.  2. Use Class PIN above to find our class account. 3. Complete the Shadow Health DCE Orientation (Due by March 11th)

Homework Activity – 2 Quiz #6: The Respiratory System