How to graphically represent lung ultrasound findings after a point of care ultrasound (POCUS)?

Graphical Representation of Lung Ultrasound Findings After POCUS

Use a standardized six-area per hemithorax approach with anatomical landmarks (sternum, anterior and posterior axillary lines) to systematically document lung ultrasound findings, recording specific sonographic patterns (A-lines, B-lines, consolidations, pleural effusions) at each location with their distribution and characteristics. 1

Structured Scanning Protocol

Anatomical Division and Documentation

• Divide each hemithorax into six zones: anterior, lateral, and posterior fields, separated by the sternum, anterior axillary line, and posterior axillary line (marked as reference lines on your documentation). 1

• Use a low-frequency curvilinear or phased-array probe placed with the orientation marker directed cranially for systematic examination. 1

• Document probe position and patient positioning (supine, semi-recumbent, or lateral decubitus) for each image acquired, as this affects interpretation. 1

Key Sonographic Patterns to Record

Normal Lung (A-Pattern)

• Presence of lung sliding: Document as present or absent, noting this represents normal pleural movement synchronized with respiration. 1

• A-lines visible: Horizontal reverberation artifacts indicating normal aeration. 1

Interstitial Syndrome (B-Pattern)

• Count and document B-lines: Multiple B-lines (≥3 per intercostal space) indicate interstitial syndrome. 1

• Semi-quantify severity by recording the number of B-lines per zone, as this directly correlates with disease severity in conditions like cardiogenic pulmonary edema. 1

• Note distribution: Bilateral, diffuse, or focal patterns help differentiate etiologies (cardiogenic edema typically bilateral and symmetric). 1

Consolidation (Tissue-Like Pattern)

• Describe as subpleural echo-poor region or tissue-like echotexture replacing normal aeration. 1

• Document air bronchograms:

  • Dynamic linear-arborescent air bronchograms (moving synchronously with ventilation) are highly specific for pneumonia and indicate patent airways. 1, 2
  • Static air bronchograms suggest atelectasis or pneumonia but are less specific. 1, 2

• Record additional features: Shape, size, margins, presence of "shred sign" (irregular borders), and any associated pleural effusion. 1

• Note the diaphragm as a landmark to distinguish intrathoracic from intra-abdominal structures. 1

Pleural Effusion

• Visualize as anechoic (black) space between parietal and visceral pleura. 1

• Document internal echoes if present, suggesting complicated effusions (exudates, empyema, hemorrhage). 1

• Estimate volume using ultrasound measurements, which correlate well with actual drainage volumes. 1

• Mark optimal drainage site if thoracentesis is indicated. 1

Pneumothorax

• Use a diagnostic algorithm approach: 1

  • Absent lung sliding + absent B-lines + absent lung pulse = pneumothorax
  • Presence of B-lines alone excludes pneumothorax at that location (B-lines originate from visceral pleura)

• Document lung point if identified, as this marks the physical boundary of pneumothorax on the chest wall and helps differentiate small from large pneumothorax. 1

Graphical Documentation Methods

Zone-Based Mapping

• Create a chest diagram with six zones per hemithorax clearly marked. 1

• Use standardized symbols for each pattern:

  • Normal A-pattern: horizontal lines
  • B-lines: vertical lines (number indicated)
  • Consolidation: shaded area with description
  • Pleural effusion: curved line with fluid symbol
  • Pneumothorax: absence markers

Serial Monitoring

• Track changes over time by documenting the same zones at regular intervals, particularly useful for monitoring treatment response in pulmonary edema (decreasing B-lines) or ARDS (changes in consolidation and aeration). 1

• Semi-quantitative scoring can be applied by assigning numerical values to aeration loss at each zone, though this is considered an advanced rather than basic skill. 1

Clinical Integration

Context-Dependent Interpretation

• Always integrate ultrasound findings with clinical context rather than interpreting images in isolation. 1

• Combine lung ultrasound with cardiac and venous ultrasound when evaluating undifferentiated respiratory failure or suspected pulmonary embolism. 1

Common Pitfalls to Avoid

• Do not rely on lung ultrasound alone to rule out pneumonia, as consolidations not reaching the pleura will be missed. 1

• Recognize that lung bullae, contusions, and adhesions can create false-positive findings for pneumothorax. 1

• Use lower-frequency probes for better evaluation of consolidation extent in deeper tissues. 1

• Ensure adequate training before clinical implementation, as operator skill significantly affects diagnostic accuracy. 1