From the Guidelines
On lateral decubitus films in cases of suspected aspiration, you will typically see a layering effect of fluid in the dependent portion of the pleural space, allowing for the detection of even small amounts of fluid. This positioning allows free-flowing pleural fluid to shift with gravity, making it visible as a layer along the dependent lateral chest wall. The key features to look for include:
- A homogeneous opacity with a horizontal upper border, indicative of free-flowing pleural fluid
- Infiltrates or consolidation in the dependent lung segments, which can be seen in aspiration cases
- The ability to differentiate between free-flowing pleural effusion and loculated fluid or parenchymal consolidation, as free fluid will move with position changes while fixed abnormalities will not, as noted in the investigation of pleural effusions 1. In the context of suspected aspiration, the lateral decubitus view is particularly valuable for detecting small effusions that may not be visible on standard upright chest radiographs, and for guiding further diagnostic and therapeutic interventions, such as thoracentesis, as discussed in the diagnosis and treatment of ventilator-associated pneumonia 1.
From the Research
Lateral Decubitus Films in Aspiration
- Lateral decubitus films are used to diagnose aspiration-related pulmonary syndromes, including aspiration pneumonitis and pneumonia 2.
- In cases of suspected aspiration, lateral decubitus films can show signs of pneumonia, such as infiltrates or consolidation, in the dependent lung 3.
- The use of lateral decubitus positioning can also help to improve ventilation-perfusion coupling in patients with mono-lateral pneumonia, although it may also cause derecruitment of the dependent lung 4.
- The diagnosis of aspiration pneumonitis or pneumonia can be challenging, and lateral decubitus films can be a valuable tool in conjunction with other diagnostic modalities, such as auscultation and laboratory tests 5.
- Aspiration is a significant risk factor for acute respiratory distress syndrome (ARDS) and can lead to increased morbidity and mortality, making accurate diagnosis and treatment crucial 6.
Findings on Lateral Decubitus Films
- Inspiratory crackles, squeaks, or wheezes may be heard on auscultation of the dependent lung in lateral decubitus positions, indicating pneumonia or other aspiration-related syndromes 3.
- Lateral decubitus films may show increased density or consolidation in the dependent lung, suggesting aspiration pneumonitis or pneumonia 2.
- The films may also show signs of airway obstruction, such as atelectasis or air trapping, in cases of large airway obstruction with a foreign body 2.
- In some cases, lateral decubitus films may be normal, even in the presence of aspiration-related syndromes, highlighting the importance of clinical correlation and other diagnostic modalities 5.