Egan Ch 43

What are the causes of atelectasis?

Atelectasis is caused by persistent ventilation with small tidal volumes or by resorption of gas distal to obstructed airways

• Gas Absorption Atelectasis: This occurs when there is a complete interruption of ventilation to a section of the lung, or a significant shift in the ventilation-perfusion (V/Q) ratio. Gas located distal to the obstruction is absorbed by the blood passing through.

  Lobar Atelectasis: This type specifically occurs when ventilation is compromised in a larger airway or bronchus.

  Compression Atelectasis: This happens when the transthoracic pressure (pressure outside the lung) exceeds the transalveolar pressure (pressure across the alveolar wall)

Identify which patients are at the greatest risk for developing atelectasis and needing lung expansion therapy.

Patients at the greatest risk for developing atelectasis and requiring lung expansion therapy commonly include those who have undergone surgery involving the upper abdomen or thorax, as pulmonary complications like atelectasis are frequent after these procedures.

A history of lung disease or significant cigarette smoking increases the risk for atelectasis

Other high-risk patient groups or factors include:

• Obesity

  Neuromuscular disorders

  Heavy sedation

  Surgery near the diaphragm

  Bed rest

  Poor cough ability

  A history of lung disease

  Restrictive chest-wall abnormalities

What type of breathing and RR do patients with atelectasis have?

Rapid, shallow breathing; fine, late-inspiratory crackles; and abnormalities on chest radiograph

Understand how lung expansion therapy can reverse atelectasis.

All modes of lung expansion therapy work to reverse atelectasis by increasing the transalveolar pressure (PAL) gradient. This crucial gradient can be achieved through two primary mechanisms:

• Decreasing the surrounding pleural pressure (Ppl): This is the mechanism behind therapies like Incentive Spirometry (IS), where a sustained maximal inspiratory (SMI) effort decreases Ppl, leading to increased lung volume.

  Increasing the alveolar pressure (Palv): This is achieved by applying positive pressure, as seen in therapies like Intermittent Positive Pressure Breathing (IPPB) and various Positive Airway Pressure (PAP) therapies.

Specifically, Continuous Positive Airway Pressure (CPAP) helps prevent atelectasis by:

• Keeping the airways open

  Improving gas exchange

  Providing positive end-expiratory pressure (PEEP)

Lung expansion therapy corrects atelectasis by increasing the PAL gradient; this can be accomplished by deep spontaneous breaths or by the application of positive pressure

List the indications, hazards, complications, and contraindications associated with general lung expansion therapy?

• Indications: To prevent or correct pulmonary complications such as atelectasis, pneumonia, and acute respiratory failure, especially in the postoperative period. Early patient mobilization is also a key preventive measure for atelectasis.

• General Hazards/Complications (Common to PAP therapies): Barotrauma, hypoventilation, gastric distention, vomiting, and aspiration. System leaks are the most common problem.

  General Contraindications (Common to PAP therapies): Hemodynamic instability and patient hypoventilation.

List the indications, hazards, complications, and contraindications associated with Incentive Spirometry (IS)?

• Indications:

  • Presence of pulmonary atelectasis.

  • Conditions predisposing to atelectasis (e.g., upper abdominal surgery, thoracic surgery, surgery in patients with COPD).

  • Presence of a restrictive lung defect associated with quadriplegia or dysfunctional diaphragm

  Contraindications:

  • Patient cannot be instructed or supervised properly.

  • Patient unable to deep breathe effectively (Vital Capacity < 10 ml/kg or Inspiratory Capacity < predicted).

  Hazards and Complications:

  • Hyperventilation and respiratory alkalosis.

  • Discomfort from inadequate pain control.

  • Pulmonary barotrauma.

  • Exacerbation of bronchospasm.

  • Fatigue.

What is the most common problem associated with lung expansion therapy?

The onset of respiratory alkalosis, which occurs when the patient breathes too quickly

List the indications, hazards, complications, and contraindications associated with Intermittent Positive Pressure Breathing (IPPB)?

• Indications

  • Atelectasis not responsive to other modalities like IS.

  • Patients at high risk for atelectasis who cannot perform IS.

    (Note: No supportive data for IPPB as a primary method for preventing or expanding atelectasis).

  Contraindications:

  • Untreated tension pneumothorax.

  • Intracranial pressure (ICP) > 15 mm Hg.

  • Hemodynamic instability.

  • Active hemoptysis.

  • Tracheoesophageal fistula.

  • Recent esophageal, facial, oral, or skull surgery.

  • Active, untreated tuberculosis.

  • Radiographic evidence of blebs.

  • Hiccups.

• Hazards: Implied by the contraindications; using IPPB in these conditions could lead to complications.

List the indications, hazards, complications, and contraindications associated with Positive Expiratory Pressure (PEP) Therapy (Including Flutter)?

• Indications: Utilized to increase the transalveolar pressure (PAL) gradient and enhance lung expansion, benefiting patients with expiratory airflow limitation.

  Contraindications (General to PAP/Flutter/CPAP):

  • Inability to tolerate increased Work of Breathing (WOB).

  • Intracranial pressure (ICP) > 20 mmHg.

  • Hemodynamic instability.

  • Acute sinusitis.

  • Recent facial, oral, or skull surgery or trauma.

  • Epistaxis.

  • Esophageal surgery.

  • Active hemoptysis.

  • Untreated pneumothorax.

  • Nausea.

  • Known or suspected tympanic membrane rupture or other middle ear pathology.

  Adverse Reactions (General to PAP therapies):

  • Increased WOB (potentially leading to hypoventilation and hypercarbia).

  • Increased intracranial pressure.

  • Cardiovascular compromise (decreased venous return).

  • Air swallowing with increased likelihood of vomiting and aspiration.

  • Claustrophobia, skin breakdown, and mask discomfort.

  • Pulmonary barotrauma.

List the indications, hazards, complications, and contraindications associated with Continuous Positive Airway Pressure (CPAP)?

• Indications:

  • Treatment of atelectasis.

  • Treatment of cardiogenic pulmonary edema.

  Contraindications (Similar to other PAP therapies):

  • Hemodynamic instability.

  • Patient with hypoventilation.

  Hazards and Complications (Similar to other PAP therapies):

  • Barotrauma.

  • Hypoventilation.

  • Gastric distention.

  • Vomiting and aspiration.

What is the goal for EzPAP?

The goal for EzPAP is to treat patients who have expiratory airflow limitation, as they respond best to this therapy. Like other Positive Airway Pressure (PAP) therapies, EzPAP aims to:

• Recruit collapsed alveoli by increasing Functional Residual Capacity (FRC).

  Decrease the work of breathing.

  Improve the distribution of ventilation through collateral channels.

  Increase the efficiency of secretion removal.

EzPAP is intended for intermittent use rather than prolonged periods.

Know when to do I.S. instruction for high-risk surgery patients.

Instruction for Incentive Spirometry (IS) should be given to high-risk surgery patients based on a careful patient assessment to determine the need for IS. IS has been proven effective in these high-risk individuals, which include patients undergoing:

• Upper abdominal surgery

  Thoracic surgery

  Surgery in patients with COPD

Effective patient teaching is crucial and should include demonstration and observation of the patient performing the technique, ensuring they can sustain their maximal inspiratory effort for 5 to 10 seconds.