Abstract
Background
Ultrasound is an innovative, noninvasive method to examine pleural effusions. Sonographic appearances are considered useful in determining the nature of pleural effusion, but there is no validated tool (similar to Light's criteria), to differentiate a transudate from an exudate using ultrasound only.
Aims
To explore the discriminative power of a score based on ultrasound criteria to differentiate a transudative pleural effusion.
Methods
A total score was computed by adding one point if any of the following findings were observed: bilateral effusions, absence of loculated fluid, anechoic fluid, non-thickened pleura, congested liver, and non-collapsing inferior vena cava.
We prospectively scored and then audited the sonographic diagnosis in 23 patients with pleural effusions. The nature of the effusion was established following a pleural aspirate on the basis of Light's biochemical criteria.
Results
By Light's criteria 10 patients had transudates and 13 had exudates. There was a correlation of 85% between the sonographic diagnosis and the biochemical diagnosis of the effusions. The average sonographic score for an exudate was 2.07 (± 1.44), while the average score for a transudate was 4.4 (± 0.70) (p<0.05). For a score of ≥4 the sensitivity and specificity for a transudate was 0.80 and 0.81.
Conclusion
A simple sonographic score can distinguish a transudative pleural effusion and may reduce the number of diagnostic aspirations for effusions likely to be transudates. Larger prospective studies are required to validate these findings.
- © 2014 ERS