PT  - JOURNAL ARTICLE
AU  - Liisa Porra
AU  - Mats Wallin
AU  - Magnus Hallbäck
AU  - Ludovic Broche
AU  - Pekka Suortti
AU  - Anssi Sovijärvi
AU  - Ferenc Petak
AU  - Walid Habre
AU  - Sam Bayat
TI  - Changes in regional distribution of gas and blood volumes within a single respiratory cycle: Effect of tidal volume, PEEP and respiratory pattern
DP  - 2014 Sep 01
TA  - European Respiratory Journal
PG  - P543
VI  - 44
IP  - Suppl 58
4099  - http://erj.ersjournals.com/content/44/Suppl_58/P543.short
4100  - http://erj.ersjournals.com/content/44/Suppl_58/P543.full
SO  - Eur Respir J2014 Sep 01; 44
AB  - Rationale: Regional lung function depends on the amount of capillary blood that interfaces with alveolar air, and both parameters dynamically change during the respiratory cycle. Although the spatial distribution of regional blood (Vb) and gas (Vg) within the lung has previously been assessed by different techniques, the dynamic changes of these parameters during the respiratory cycle have not been directly quantified.Methods: We used K-edge subtraction synchrotron CT imaging and a post-gating reconstruction sequence to quantitatively image regional Vg, tissue density and Vb in 6 anaesthetized healthy and mechanically ventilated rabbits. Images were repeatedly collected during ventilation and steady-state inhalation of 70% Xe, or iodine infusion. Data were acquired in 2 different axial chest positions, PEEP, VT and breathing patterns. Regional Vg and Vb were calculated from xenon and iodine distributions, respectively.Results: A video of the dynamic changes in gas and blood volume during the respiratory cycle was obtained. Changes in the Vg and Vb are shown in the Figure.Figure: Relative lung gas and blood volumes during 2 successive respiratory cycles.Conclusions: This study shows for the first time, the relation between regional blood and gas volume during the respiratory cycle. The dynamics of Vg and Vb were affected both by VT and PEEP level.