Point of Care Lung Ultrasound Recommendations
Article: Volpicelli G, Elbarbary M, Blaivas M, et al. International evidence-based recommendations for point-of-care lung ultrasound. Intensive Care Med. 2012;38(4):577-591. doi:10.1007/s00134-012-2513-4
The Idea: Lung ultrasound is applied in a variety of medical settings and thus has produced differences in approaches, techniques utilized, and nomenclature. To better standardize its application internationally and across clinical contexts, it was decided that a collection of guidelines/consensus statements were necessary. The aim was to construct a unified approach to lung POCUS with these evidence-based guidelines and thereby guide implementation, development, and training on use of lung ultrasound in all of its relevant settings.
The Guideline Process: The key components of guideline construction involved 1) determining the level of quality of evidence, and 2) developing the recommendation. An international, multidisciplinary panel of 28 experts was responsible for literature review, guideline construction, guideline grading, and the creation of the final consensus recommendations.
The Guideline Results: A total of 320 references were individually appraised. A total of 73 proposed statements were examined by the panel, with 6 statements going unadopted, 2 statements given weak/conditional recommendations, and strong recommendations given to the remaining 65 statements.
The Key Takeaways:
1. Pneumothorax: The four sonographic signs of pneumothorax include the presence of lung point(s), absence of lung sliding, absence of B-lines, and absence of lung pulse. Finding the lung point is not necessary to diagnose pneumothorax if there is both absence of pleural line movement (sliding or pulse) and absence of B-lines. Lung ultrasound is more accurate than CXR, particularly in ruling out pneumothorax.
2. Interstitial Syndrome: There is a tight correlation between interstitial involvement of lung diseases and B-lines using an eight-region sonographic technique. A positive region is defined by the presence of three or more B-lines between two ribs. A positive exam is two or more positive regions. B-line patterns can differentiate focal and diffuse interstitial involvement and when paired with other findings can differentiate cardiac from parenchymal lung disease. For more precise quantification of interstitial disease, a 28-scanning site technique can be utilized.
3. Lung Consolidation: A subpleural, echo-poor region or one with a tissue-like echotexture are the sonographic signs of lung consolidation. The specific cause of the lung consolidation (infection, PE, lung cancer, atelectasis, contusion etc.) can be determined using a variety of sonographic features of the lesion (i.e. Air bronchograms). Lung ultrasound has good accuracy compared to CXR and in pleuritic pain is superior to CXR due to its ability to identify radio-occult pulmonary conditions. In mechanically ventilated patients, LUS is more accurate than CXR in detecting and distinguishing various consolidation types.
4. Monitoring Lung Diseases: LUS is able to semi-quantify cardiogenic pulmonary edema disease severity and track therapeutic response by evaluating the number and character of B-lines. LUS can also evaluate and track aeration changes in acute lung parenchymal diseases (ARDS, pneumonia, ALI) using progressive sonographic changes: normal pattern, multiple spaced B-lines, coalescent B-lines, consolidation.
5. Neonatology and Pediatrics: Lung US allows diagnosis of respiratory distress syndrome and pneumonia in newborns with accuracy similar to CXR. In contrast to the nonspecific findings of CXR, LUS has unique findings in transient tachypnea of the newborn, which are bilateral confluent B-lines in the dependent areas of the lung and normal/near-normal appearance of the lungs in the superior fields. Pediatric LUS signs are similar to those found in adults.
6. Pleural Effusion: Pleural effusion is visualized as an anechoic space between the visceral and parietal pleura. Visualization of internal echoes is highly suggestive of exudative effusion or hemothorax. If the effusion is anechoic, then a thoracentesis or clinical correlation is required to differentiate between exudate and transudate. LUS accuracy is higher than CXR for effusion, particularly with an AP view in a supine patient. LUS performance is almost equivalent to CT scan in diagnosing effusion.
The Big Picture: LUS in the emergency setting is advantageous, especially in terms of decreasing radiation exposure, efficiency and time saved, and as imaging guidance for certain life-saving therapies.
Post by Dillon Warr, MS4