Proceedings of The Physiological Society

Physiology 2016 (Dublin, Ireland) (2016) Proc Physiol Soc 37, PCA083

Poster Communications

Improved prediction of post-pneumonectomy lung function

M. Kang1, H. Guénard2, M. Pichelin3, I. Katz3, B. Sapoval1

1. Ecole Polytechnique, Palaiseau, France. 2. Université Bordeaux 2, Bordeaux, France. 3. Air Liquide Santé International, Jouy-en-Josas, France.

An important problem in lung cancer surgery is the prediction of post-operative respiration (Brunelli et al., 2013). A new approach to this question is made possible by the recent bottom up model of oxygen capture during the respiratory cycle (Kang et al. 2015). This model allows for a quantitative calculation of the respective role of ventilation (VE) and cardiac output (Q) on oxygen uptake (VO2). The results are shown in the figure that represents the VO2 isolines of a healthy lung as a function of VE and Q. The predictive method is based on the idea that the resection of a fraction of the lungs volume does not modify strongly Q so that the local blood flow rate in the remaining volume is increased accordingly. Consider for example the case where half the lung volume has been resected. As a consequence the local blood flow is doubled but the local ventilation would remain the same if the diaphragm motion is not modified. This is shown in the figure by shifting from A (for which VE(normal) = 7.5 L/min; Q(normal) = 5L/min and VO2(normal) = 220mL/min) to B (same ventilation, local Q(B) = 2Q(normal) = 10L/min and VO2(post) = (1/2)VO2(B) = (1/2)(0.35) L/min = 0.175L/min which is insufficient. To recover a normal VO2, one has to increase the ventilation of the remaining lung by shifting from B to C where VO2(post) = (1/2)VO2(C) = 220mL/min = VO2(normal). Not shown here are the abacus giving PAO2 and saturation abacus computed from Kang et al. (2015) that confirm that provided the increase in ventilation, normal values will be recovered. The conclusion is that, a constant cardiac motion, a ventilation increase either spontaneous or artificial are needed to recover normal VO2. The method can be extended to any resection fraction and to COPD patients that exhibit impaired ventilation before pneumonectomy.

Where applicable, experiments conform with Society ethical requirements