Discriminating transudates and exudates in dogs with pleural effusion: diagnostic utility of simplified Light's criteria compared with traditional veterinary classification

Abstract

<jats:sec><jats:title>Objectives</jats:title><jats:p>To determine whether the simplified Light’s criteria (ie, pleural effusion lactate dehydrogenase concentration and serum total protein) can identify the pathophysiology of pleural effusion formation in dogs, and to assess whether these criteria were more accurate than the traditional veterinary classification based on pleural effusion total protein (TPp) and nucleated cell count (TNCCp).</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>This is a cross-sectional study including 100 dogs with pleural effusion. The aetiology of effusion was used to classify the pathophysiology of its formation. Parameters measured included the simplified Light’s criteria, TPp and TNCCp. The diagnostic utility of the two methods in classifying pleural effusion formation was evaluated.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Seven transudates due to decreased colloid osmotic pressure, 18 transudates due to increased hydrostatic pressure gradient and 75 exudates were included in the study. The simplified Light’s criteria misclassified 2 of 75 exudates (98 per cent overall accuracy). The traditional veterinary classification scheme misclassified 31 of 75 exudates and 12 of 18 increased hydrostatic pressure gradient transudates (57 per cent overall accuracy). The frequency of agreement between the simplified Light’s criteria and the traditional veterinary classification with the true nature of the pleural effusion was significantly different (P&lt;0.001).</jats:p></jats:sec><jats:sec><jats:title>Clinical significance</jats:title><jats:p>The simplified Light’s criteria were highly accurate in discriminating exudates from transudates, while TPp and TNCCp had no diagnostic value in doing so.</jats:p></jats:sec>

Evaluation of a new multiple regression model based on biochemical parameters for the distinction of canine exudates and transudates

“…Thus, different transudative or exudative effusions can be formed secondary to neoplasia. In a study by Zoia et al, who used similar methods to those used in our study, 18 any effusion formed secondary to intracavitary neoplasia was considered to be an exudate. Intracavitary tumors can form transudates when compressing adjacent lymphatic or blood vessels, 20,48 creating increased intravascular hydraulic pressure leading to localized edema and effusion formation.…”

“…These were established by the attending clinician, based on the assessment of history and signalment; physical examination; laboratory data; imaging studies; and/or necropsy and histopathology results, according to criteria represented in Table 1. The list of criteria was adapted from a recent study where similar methods were applied 18 . A final diagnosis was established when all of the respective criteria were met.…”

“…The list of criteria was adapted from a recent study where similar methods were applied. 18 A final diagnosis was established when all of the respective criteria were met. Forty-six cases remained that either had no diagnosis, a suspected diagnosis only, or a diagnosis unrelated to the effusion formation.…”