What is the diagnosis and treatment for lung atelectasis (partial lung collapse)?

From the Guidelines

Lung atelectasis should be managed with higher PEEP levels in adult patients with moderate or severe acute respiratory distress syndrome (ARDS) to reduce atelectasis and improve oxygenation, as evidenced by a conditional recommendation with moderate confidence in effect estimates 1.

Causes and Consequences of Atelectasis

Atelectasis is the collapse or closure of a lung or part of a lung, resulting in reduced or absent gas exchange. It occurs when the alveoli (air sacs) become deflated or filled with fluid. If left untreated, atelectasis can lead to hypoxemia, pneumonia, and respiratory failure, making prompt recognition and management essential. Atelectasis can result from various causes, including airway obstruction, external compression of lung tissue, surfactant deficiency, or as a complication of various respiratory conditions.

Treatment and Management

Treatment of atelectasis depends on the cause and severity but typically includes addressing the underlying condition, encouraging deep breathing exercises, incentive spirometry, chest physiotherapy, and early mobilization. For significant atelectasis, bronchoscopy may be necessary to remove mucus plugs or foreign bodies obstructing airways. Supplemental oxygen therapy is often provided to maintain adequate oxygenation. Patients should be positioned with the good lung down to improve ventilation to the affected area.

Prevention Strategies

Prevention strategies include early ambulation after surgery, adequate pain control to allow for deep breathing, regular position changes for bedridden patients, and smoking cessation. Atelectasis occurs commonly after surgery, particularly abdominal or thoracic procedures, due to shallow breathing from pain or anesthesia effects.

Evidence-Based Recommendation

The use of higher PEEP levels in adult patients with moderate or severe ARDS is supported by evidence from an individual patient data meta-analysis (IPDMA) of three large randomized controlled trials (RCTs), which showed a significant reduction in mortality with higher PEEP 1. Additionally, recruitment maneuvers (RMs) have been shown to be associated with lower mortality and improved oxygenation in patients with ARDS, although the evidence is based on a single trial without cointervention 1.

Key Considerations

• Higher PEEP levels can improve alveolar recruitment, reduce lung stress and strain, and prevent atelectrauma in patients with ARDS.
• RMs can reduce atelectasis and increase end-expiratory lung volume, but may be associated with complications such as hemodynamic compromise and barotrauma.
• The choice of treatment should be individualized based on the patient's specific condition and response to therapy.

From the FDA Drug Label

Acetylcysteine is indicated as adjuvant therapy for patients with abnormal, viscid, or inspissated mucous secretions in such conditions as: ... Atelectasis due to mucous obstruction N-acetylcysteine (INH) may be used as adjuvant therapy for atelectasis due to mucous obstruction 2.

• Key indication: Atelectasis due to mucous obstruction
• Main use: Adjuvant therapy to help relieve abnormal, viscid, or inspissated mucous secretions

From the Research

Definition and Causes of Lung Atelectasis

• Lung atelectasis is a state of collapsed and non-aerated region of the lung parenchyma, which is otherwise normal 3.
• Atelectasis may occur in three ways: (i) airway obstruction; (ii) compression of parenchyma by extrathoracic, intrathoracic, chest wall processes; and (iii) increased surface tension in alveoli and bronchioli 3.
• Pulmonary atelectasis is mainly caused by 3 factors: compression, gas absorption, and lack of surfactant, with compression and gas absorption being the 2 most commonly implicated factors 4.

Diagnosis and Treatment of Lung Atelectasis

• Chest radiographs using both the anterior-posterior and lateral projections are mandatory to document the presence of atelectasis 3.
• Differentiation from lobar consolidation may be a clinical dilemma 3.
• The treatment of atelectasis varies depending on duration and severity of the causal disease, and may include chest physiotherapy, postural drainage, bronchodilator and anti-inflammatory therapy, and removal of persistent mucous plugs by bronchoscopy 3, 5.
• Alveolar recruitment strategies, such as using positive end-expiratory pressure or a high tidal volume, may be used to prevent atelectasis or to reopen collapsed lung tissue 4.

Management of Lung Atelectasis in Specific Contexts

• In postoperative patients, mechanical ventilation and endotracheal intubation can cause airway damage and inflammation, resulting in excessive mucus secretions and increasing the risk of respiratory failure post extubation 5.
• Conservative oxygen therapy (COT) may be associated with decreased radiological evidence of atelectasis, earlier weaning from mandatory ventilation modes, and earlier first trial of spontaneous ventilation in mechanically ventilated intensive care unit patients 6.
• Bronchoscopic aspiration and lavage, as well as chest physiotherapy, may be effective in removing retained secretions or mucus plugs and preventing lung collapse in postoperative cases 5.