chapter 43

Understanding Atelectasis

  • Atelectasis: Collapse of the lung parenchyma, primarily involving alveoli. Occurs due to various factors including shallow breathing, obstruction, or post-operative conditions.

    • Alveolar Recruitment: Process of reopening collapsed alveoli.

Importance of Lung Expansion Therapy

  • Goal: To prevent or correct atelectasis through lung expansion therapy or hyperinflation.

  • Emphasis on Restrictive Lung Diseases: Such as atelectasis; not typically beneficial for patients with COPD due to their already inflated lungs.

Mechanisms of Atelectasis

  • Types of Atelectasis:

    • Passive Atelectasis: Common with post-operative patients; results from shallow breathing.

    • Resorption/Gas Absorption Atelectasis: Occurs when an airway is obstructed (e.g., mucus plug), preventing ventilation to affected alveoli and causing gas absorption into the bloodstream.

    • Compression Atelectasis: Due to external pressure on the lung, such as pneumothorax (air in the pleural space) or pleural effusion (fluid in the pleural space).

Risk Factors for Atelectasis

  • Post-operative Patients: Common due to factors such as:

    • General anesthesia impacts mucociliary function and humidity.

    • Shallow breathing due to pain from surgery.

    • Decreased surfactant production, leading to increased surface tension and alveolar collapse.

    • Bedridden patients or those with obesity affecting diaphragm movement.

  • High-risk Groups:

    • Patients with a history of mucus-producing diseases, neuromuscular disorders, morbid obesity, or upper abdominal surgery.

Physiological Concepts

  • Minute Ventilation (MV): Refers to the total volume of air entering or leaving the lungs per minute, calculated as:

    • Formula: MV = Tidal Volume (TV) x Respiratory Rate (RR)

  • Alveolar Ventilation (AV): Refers to how much fresh air reaches the alveoli; more critical for effective gas exchange:

    • Formula: AV = (TV - Dead Space) x RR

Signs of Atelectasis

  • Increased respiratory rate (often shallow).

  • Possible symptoms overlapping with pneumonia, but typically without fever and purulent sputum.

  • Physical examination may reveal diminished breath sounds or late inspiratory crackles.

  • Trachea deviation and hyperinflation may occur on chest imaging.

Lung Expansion Therapy Techniques

  • Deep Breathing Exercises: Teaching patients the importance of taking deeper breaths to avoid atelectasis.

    • Example: Slow deep inhalation through the nose, holding it briefly, then exhaling slowly.

  • Incentive Spirometer (IS): A device to encourage deep breathing by having patients achieve specific volume goals. Ideal for post-operative care to prevent atelectasis.

    • Sustained Maximal Inspiration (SMI): Patients are taught to breathe in deeply and sustain the breath to allow lung expansion.

    • Indicated for patients who can cooperate and understand instructions.

  • Diaphragmatic Breathing: Teaching patients to use their diaphragm effectively to improve breathing mechanics, increase lung volumes, and provide relaxation benefits.

Key Volume and Capacity Measurements in Pulmonary Function Tests

  • Volumes:

    • Tidal Volume (TV): Air inspired/expired with each breath.

    • Inspiratory Reserve Volume (IRV): Additional air that can be inhaled after a normal tidal inhalation.

    • Expiratory Reserve Volume (ERV): Additional air that can be exhaled after a normal tidal exhalation.

    • Residual Volume (RV): Air remaining in the lungs after complete exhalation.

  • Capacities:

    • Total Lung Capacity (TLC): Maximum amount of air the lungs can hold.

    • Functional Residual Capacity (FRC): Volume of air remaining after normal expiration. Critical in assessing lung health, especially in restrictive diseases.

Contraindications and Hazards of Incentive Spirometry

  • Not Recommended When:

    • Patients can't cooperate or follow instructions.

    • Vital capacity is < 10mL/kg of ideal body weight.

    • Significant pain from deep breathing.

  • Hazards: Include hyperventilation, fatigue, and potential hypoxemia due to interruptions in oxygen therapy.

Summary of Key Teaching Points

  • Reinforcing the importance of regular deep breathing and lung expansion exercises post-surgery.

  • Emphasizing patient comfort and understanding to facilitate compliance with lung expansion therapies.

  • Reminder of the role of diaphragmatic breathing and incentive spirometry in promoting effective lung function.

During a huff cough, the epiglottis is typically open. This allows air to flow out of the lungs without obstruction, helping to effectively clear mucus from the airways while minimizing the risk of airway irritation or damage that can occur with a forceful, traditional cough.

During a huff cough, the epiglottis is typically open. This allows air to flow out of the lungs without obstruction, helping to effectively clear mucus from the airways while minimizing the risk of airway irritation or damage that can occur with a forceful, traditional cough.

Restrictive lung defects refer to conditions that cause a reduction in lung volume and restrict airflow. These defects can be due to intrinsic factors like lung diseases (e.g., pulmonary fibrosis), which involve stiffening of lung tissue, or extrinsic factors such as obesity or diseases affecting the chest wall (e.g., scoliosis) that restrict lung expansion.

Key characteristics of restrictive lung defects include:

  • Decreased total lung capacity (TLC)

  • Reduced forced vital capacity (FVC)

  • Normal or increased forced expiratory volume in 1 second (FEV1) to FVC ratios

Common examples of restrictive lung diseases:

  • Pulmonary fibrosis

  • Interstitial lung disease

  • Pleural effusion

  • Neuromuscular disorders (e.g., Amyotrophic Lateral Sclerosis)

Treatment often involves addressing the underlying cause, pulmonary rehabilitation, and in some cases, oxygen therapy.