Notes
As reflected by this calculator too, there are several different published methods and equations that aid in estimating the approximate volume of the pleural effusion.
The equations are as follows:
- Balik formula: effusion volume (mL) = maximum perpendicular distance between the pulmonary surface and chest wall at end-expiration with mild trunk elevation at 15° (mm) x 20
- Eibenberger formula: effusion volume (mL) = [47.6 x maximum perpendicular distance between the pulmonary surface and chest wall at maximal inspiration (mm) ] – 837
- Note that the Eibenberger formula returns false negative values if the distance between pleural layers is below 17 mm. This calculator refuses to calculate and shows a warning message in this case. For very small effusions the Balik formula should be preferred.
- First Goecke formula: effusion volume (mL) = craniocaudal extent of the effusion measured at the dorsolateral chest wall in an erect or sitting position (mm) x 90
- Second Goecke formula: effusion volume (mL) = [ craniocaudal extent of the effusion measured at the dorsolateral chest wall in an erect or sitting position (mm) + distance between the lung base and the mid-diaphragm (mm) ] x 70
- (Bolanle Olubunmi Ibitoye, Bukunmi Michael Idowu, Akinwumi Babatunde Ogunrombi, Babalola Ishmael Afolabi. Ultrasonographic quantification of pleural effusion: comparison of four formulae. (2017) Ultrasonography. 37 (3): 254.)
- Appropriate positioning of the ultrasound probe is crucial in order to make any use of these calculations. If unfamiliar, refer to this PubMed central open access article where the correct position is illustrated.
- In general, the erect/sitting Goecke formulas yield a more precise estimate of the pleural effusion volume, and thus are preferred if the patient positioning is possible.
For further information we recommend you to visit the relevant article on Radiopaedia.org too.
Last updated: 2021-08-17