From the Guidelines
Minor atelectasis is primarily caused by intraoperative factors, including general anesthesia, which can lead to decreased functional residual capacity, increased heterogeneity of lung expansion, and cyclic lung overstress, as seen in roughly 90% of patients undergoing general anesthesia 1.
Causes of Minor Atelectasis
The causes of minor atelectasis can be multifactorial, including:
- Airway obstruction due to mucus plugs, foreign bodies, tumors, or bronchospasm
- Compression of lung tissue from pleural effusion, pneumothorax, enlarged heart, tumors, or abdominal distention
- Surfactant deficiency, which can occur in premature infants or with lung injury
- Post-surgical atelectasis, especially after abdominal or thoracic procedures, due to shallow breathing from pain and anesthesia effects
- Prolonged bed rest or immobility, preventing normal lung expansion and mucus clearance
- Other factors such as obesity, smoking, and chronic respiratory conditions that impair normal breathing mechanics
Importance of Intraoperative Ventilation
Intraoperative ventilation strategies that avoid derecruitment without causing over-distension of alveoli may decrease postoperative pulmonary risk by improving perioperative oxygenation and respiratory mechanics, and reducing oxidative stress, inflammatory response, and lung injury 1. Individualized PEEP can prevent progressive alveolar collapse, and recruitment maneuvers can reverse alveolar collapse, but have limited benefit without sufficient PEEP 1. It is essential to address the underlying cause of atelectasis, encourage deep breathing exercises, incentive spirometry, early mobilization, and proper pain management to resolve minor atelectasis. Persistent cases may require bronchoscopy to remove obstructions or respiratory therapy to improve airway clearance.
From the Research
Causes of Minor Atelectasis
The causes of minor atelectasis, also known as partial lung collapse, can be attributed to several factors, including:
- Airway obstruction 2
- Compression of parenchyma by extrathoracic, intrathoracic, chest wall processes 2
- Increased surface tension in alveoli and bronchioli 2
- Mucus plugging, which can be caused by various conditions such as pneumonia 3, 4
- Airway damage and inflammation resulting from mechanical ventilation and endotracheal intubation, leading to excessive mucus secretions 4
Mechanisms of Atelectasis
Atelectasis can occur through different mechanisms, including:
- Obstruction of the airways by mucus plugs or foreign bodies 5, 3
- Compression of the lung parenchoa by extrathoracic or intrathoracic processes 2
- Increased surface tension in the alveoli and bronchioli, leading to collapse of the lung tissue 2
Clinical Presentations
Atelectasis can present in various ways, including: