RT Journal Article SR Electronic T1 Determination of total lung capacity (TLC) without body plethysmography JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 1793 VO 42 IS Suppl 57 A1 Inon Cohen A1 Adam LaPrad A1 Ori Adam A1 Zachi Peles A1 Robert Brown A1 Julian Solway A1 Jeffrey Fredberg YR 2013 UL http://erj.ersjournals.com/content/42/Suppl_57/1793.abstract AB We report here a new method to determine TLC that requires neither body plethysmography (PLETH), gas dilution, nor thoracic imaging. With cheeks supported, the subject breathes through a flow interruption valve downstream of a parallel chamber of known gas volume, comprising a so-called MiniBox (Fig.1 inset). The subject also performs standard spirometry. Pressure and flow metrics were derived from both these maneuvers in a training population, as well as TLCPLETH measured on the same day (Platinum Elite, MGC, and ZAN 500, nSpire). Data mining methods were used to generate a formula from which we calculated TLC of any individual subject. Our population comprised 59 healthy adult women (31.5+15.5y, 23.3+4.9 BMI), 83 healthy adults men, (31.0+14.9y, 24.1+3.3 BMI), 25 patients with restrictive disease (48.8+16.4y, 29.4+6.8 BMI), and 101 patients with obstructive disease (62.9+11.9y, 27.7+4.9 BMI). Across this heterogeneous population we found TLCMiniBox=1.01TLCPLETH, r=0.91 (Pearson), CI: 0.922-0.88 (Fig.1). The coefficient of variation (CV) for repeated trials was 5.1%. These results establish a robust new method for accurate, rapid, and reproducible determination of TLC not only in healthy subjects but also in patients with a range of obstructive and restrictive disorders. Because it is compact, rapid, and accurate, this method is suitable for use in a physician office.This work was sponsored by PulmOne Ltd., Ra’anana, Israel.