Inhaled Medications

Inhaled Medications

Respiratory Assessment

• Key Components of Assessment:

  • History

  • Lung Sounds

  • Respiratory Effort

  • Respiratory Rate

  • Pulse Oximetry

  • Arterial Blood Gas (ABG) Analysis

  • Diagnostics (Bronchoscopy, X-ray, CT, MRI, Biopsy)

Lung Problems

• Pneumonia: Fluid buildup and infection (can be bacterial or viral)

• Pulmonary Edema: Fluid in the alveoli; often a result of heart failure, treated with medications such as Lasix, Morphine, and Nitrates.

• Pleural Effusion: Fluid in pleural spaces, reduces lung volume, leads to shortness of breath (shob), may occur due to infection; treated with chest tubes or catheter for fluid removal.

• Pulmonary Embolus: Blood clot in the lungs, typically from DVT in legs or arms that gets dislodged; treatment includes Heparin drip and oxygen; can be difficult to treat once lodged in the lung.

• Asthma: Constricted airways and airway inflammation, consolidated lung spaces, decreases air movement and gas exchange in the lungs.

• COPD: Involves chronic bronchitis (airway inflammation) and emphysema (consolidated lung space).

Gas Movement and Gas Exchange

• Key Structures Involved:

  • Airways (Trachea, Bronchial tubes)

  • Alveoli (Oxygen exchange occurs here)

  • Impact of excess mucus compared to healthy bronchiole and alveoli.

Inhaled Drugs

• Two Basic Classes:

  • Bronchodilators

  • Anti-inflammatory Agents

Bronchodilators

• Xanthines (Older Class): Caffeine, Theophylline

• Sympathomimetics and Anticholinergics (Most Common):

  • Uses: Class of choice for acute shortness of breath, dilates bronchial passages, increases respiratory rate (RR) and depth, opens up the airways.

  • Examples:

    • Albuterol (first option, sympathetic agonist, intended for lighter short-term use)

    • Epinephrine (non-selective, used in emergent situations)

      • Relaxes the airway and helps the patient move air adequately

      • affects beta one (heart) and alpha one receptors

More Examples of Bronchodilators

• Long-Acting Beta Agonists (LABA): Salmeterol, Formoterol

• Short-Acting Beta Agonist (SABA): Levalbuterol

  • Affects Beta 1 (heart) and Beta 2 (lungs) receptors

Effects of Sympathomimetics

• Physiological Responses:

  • Sympathetic stimulation

  • Increased heart rate

  • Increased blood pressure

  • Decreased renal and GI perfusion

  • Bronchodilation

  • Increased RR

  • Sweating

  • By using an inhaler, you limit the systemic side effects

Other Bronchodilators: Anticholinergics

• Ipratropium: Less effective than Albuterol, commonly used with it for chronic conditions, does not cause sympathetic stimulation.

  • Parasympathetic Antagonist

  • Commonly used in conjunction with albuterol for chronic use

  • Counteracts parasympathetic nervous system for bronchodilation

  • No Sympathetic Stimulation

  • Disrupts vagus enervation

• Mechanism: Disrupts vagal enervation, acts as a parasympathetic antagonist for bronchial dilation.

Anticholinergic Effects

• Reduced systemic effects when using inhalers:

  • Smooth muscle dilation of bronchi

  • Side effects: Dry mouth, urinary retention

Anti-Inflammatories

• Glucocorticoids:

  • Budesonide: for long-term prophylaxis.

  • Inhalation decreases systemic side effects; all steroids must be weaned off especially after prolonged use.

  • Inhaled steroids for long term use and daily maintenance to avoid systemic side effects.

Anti-Inflammatory Use

• To note: Not for acute exacerbations; takes 2-3 weeks to reach effective levels.

• Post-use recommendation: Rinse mouth with water post inhalation to avoid development of thrush.

Steroid Side Effects

• Common Side Effects:

  • Hyperglycemia

  • Thrush

  • Osteoporosis

  • Immunocompromise

  • Increased risk of glaucoma (particularly with long-term use).

  • Effects are more likely to happen with systemic use and are less likely with inhaled medications.

Inhaling Advantages

• Three Key Advantages:

  • Increased therapeutic effect at the site of action.

  • Decreased systemic side effects.

  • Rapid onset of action; works quickly.

Metered Dose Inhalers (MDI)

• Administration Tips:

  • Requires coordination: inhale before activation.

  • Only 10% reaches the lungs; spacers can increase this to about 20%, allowing more medication to reach the lungs.

  • Steps for MDI Use:

    • Prime 4 times before first use.

    • Shake inhaler.

    • Inhale deeply before activation, hold breath, and rinse mouth after use.

    • Ensure to wait 1-5 minuted between each dose.

Dry Powder Inhalers (DPI)

• Advantages:

  • Less coordination needed, activated by inhalation.

  • Approximately 20% of medication reaches the lungs; do not breathe it back out.

  • The quality of inspiration affects the drug delivery

Nebulizers

• How It Works: Drug is mistified and inhaled over several minutes, very simple, and uses equipment.

• Benefit: More drug reaches the lungs compared to other forms of inhalation.