Dear Cesar,

Recently I found a review saying that we still don't have a method for quantification of lung lining fluid:

"There are, however, no alternatives to in vivo determinations of lung surface area and lung lining fluid."

Find the citation below,

Article Measurements of Deposition, Lung Surface Area and Lung Fluid...

Hope it helps,

Marcos

You may find this paper helpful:

https://journals.physiology.org/doi/full/10.1152/jappl.2000.89.2.672?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org

Thank you so much!!!!