Validation of equations for pleural effusion volume estimation by ultrasonography

摘要

Scopo Per convalidare l’accuratezza di equazioni che stimano il volume versamento pleurico. Metodi Abbiamo testato le equazioni che hanno usato le misurazioni semplici. Sono state prese tre misure: altezza di effusione (H), la distanza tra il polmone collassato e la parete toracica (C) e la distanza tra polmone e diaframma (D). Il versamento e` stato aspirato e il volume e` stato registrato. Coefficiente di correlazione intra-classe (ICC) e` stato utilizzato per determinare l’accuratezza predittiva delle misurazioni. Risultati 46 pazienti sono stati inclusi. L’equazione piu` accurata nel predire il volume di effusione era (H + D) × 70 (ICC 0,83). La piu` semplice equazione accurata era H × 100 (ICC 0,79). Conclusione L’altezza del versamento pleurico misurato con ecografia fornisce una stima ragionevole del volume di versamento. La distanza tra la base del polmone e il diaframma migliora la precisione.%Purpose To validate the accuracy of previously published equations that estimate pleural effusion volume using ultrasonography. Methods Only equations using simple measurements were tested. Three measurements were taken at the posterior axillary line for each case with effusion: lateral height of effusion (H), distance between collapsed lung and chest wall (C) and distance between lung and diaphragm (D). Cases whose effusion was aspirated to dryness were included and drained volume was recorded. Intra-class correlation coefficient (ICC) was used to determine the predictive accuracy of five equations against the actual volume of aspirated effusion. Results 46 cases with effusion were included. The most accurate equation in predicting effusion volume was (H + D) × 70 (ICC 0.83). The simplest and yet accurate equation was H × 100 (ICC 0.79). Conclusion Pleural effusion height measured by ultrasonography gives a reasonable estimate of effusion volume. Incorporating distance between lung base and diaphragm into estimation improves accuracy from 79% with the first method to 83% with the latter.