Chapter 11 Intensive Care Unit

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SECTION 1 • Techniques and Methods in Critical Care

Lung Abscess

Empyema

FIGURE 11-9. Top: Large right upper lobe lung abscess with thick cavity wall and air–fluid level indicating communication with the airway. Bottom: Loculated empyema of the right posterior pleural space. The lateral view demonstrates that the opacity is not rounded, abuts the ribs, and is not entirely encapsulated by aerated lung.

intrapulmonary collections are usually smaller, more dense, and rounded. Lung abscesses and liquid-filled bullae tend to project similar diameters on both AP and lateral films (Fig. 11-9 Top panels). The air–fluid level of pleural fluid collections must abut the chest wall on either AP or lateral film (Fig. 11-9 Bottom panels). Fluid collections that cross a fissure line on upright films are located within the pleural space. Lung abscesses generally have distinct, thick, shaggy walls with irregular contours, unlike most liquid- filled bullae and pleural fluid collections. As body

position is altered, pleural fluid collections frequently undergo marked changes in shape or contour. CT scanning reliably differentiates the two conditions. Postthoracotomy Changes After pneumonectomy, fluid accumulates in the vacant hemithorax over days to months. Whereas the absolute fluid level is of little significance, changes in the level of fluid are important. A rapid decline in the fluid level should prompt concern for a