Pathophysiology of Asthma HYPERRESPONSIVENESS OF AIRWAYS that results in: Usually, reversible constriction of bronchial smooth muscle (bronchoconstriction). Hypersecretion of mucus Mucosal inflammation and edema (Considered more a disease of inflammation than obstruction: obstruction occurs secondarily)
Emphysema IRREVERSIBLE destruction of alveolar walls which decreases surface area for gas exchange. Loss of lung elasticity: “springs” that hold open alveolar walls are “sprung” and collapse. Air becomes trapped and distal airways hyperinflate and rupture.
Medications that Treat Respiratory Disease Steroids –REDUCE INFLAMMATION. –CONSIDERED A DRUG OF PREVENTION –Not used acutely –Best to use spacer (aerochamber) to decrease systemic effects. –Rinse & spit after use. –Commonly ends in “sone,” “olone”
Bronchodilators Fast acting USED ACUTELY. Open airways. Most bronchodilators are given via nebulizer, MDI or DPI. Beta adrenergic agonists (erol, enol) Common side effects are palpitations &, tachycardia. Note: If patients are using more than one canister a month (200puffs), their disease is in poor control. Don’t use as “fire extinguisher.” Ask why is fire breaking out?
Bronchodilators Bronchodilators (fast or slow acting) work by relaxing muscle walls and thereby making the air passage larger.
Bronchodilators –Methylxanthines: theophylline Aminophylline second line drug given when extra treatment is needed. Given IV or PO. Most common side effects of aminophylline are tachycardia, shakiness, and palpitations. –Anticholinergics: relax bronchial smooth muscle but less effective than beta agonists. –http://www.use-inhalers.com/http://www.use-inhalers.com/
Respiratory Preventatives Mast Cell Stabilizers Not used acutely. Used to prevent an exacerbation of asthma. Examples of mast cell stabilizers: Cromolyn (Intal) Nedocromil (Tilade) Inhibit histamine release from mast cells thus decreasing immune response.
Respiratory Preventatives Leukotriene Modifiers –Not used acutely. Used to prevent an exacerbation of asthma –Leukotriene Modifiers: interfere with synthesis or block the action of leukotrienes which cause inflammation. Examples are: “lukast Montelukast (Singulair)
Nutritional Therapy Weight loss and malnutrition are common Pressure on diaphragm from a full stomach causes dyspnea Difficulty breathing while eating leads to inadequate consumption Drink fluids in between meals Rest at least 30 minutes prior to eating Frequent small meals (high calorie and protein) Prepare foods in advance
Respiratory Therapy Aerosol nebulization therapy –Deliver suspension of fine particles of liquid (medication) in a gas –Easy to use –Must be kept clean at home to prevent bacterial growth
Managing Oxygen Liter Flow Outdated information: Never exceed 2 liters of oxygen per nasal cannula for patients with chronic lung disease because can knock out drive to breath. This can occur but is rare. New standard is to use oxygen saturation level as guide to how much oxygen to deliver. Increase oxygen level to maintain therapeutic oximetry. If Sp02 ↓ with ↑ O2, stop. Hinkle, MD, SIU Chief of Pulmonary Medicine