EMPHYSEMA

Transpleural ventilation of explanted human lungs

Cliff K Choong¹, Peter T Macklem², John A Pierce³, Stephen S Lefrak³, Jason C Woods⁴, Mark S Conradi⁴, Dimitry A Yablonskiy⁵, James C Hogg⁶, Kimiaki Chino¹, Joel D Cooper¹

¹ Division of Cardiothoracic Surgery, Washington University School of Medicine, St Louis, Missouri, USA
² Meakins-Christie Laboratories, Montreal Chest Institute, McGill University Health Centre Research Institute, Montreal, Quebec, Canada
³ Division of Pulmonary and Critical Care Medicine, Washington University School of Medicine, St Louis, Missouri, USA
⁴ Department of Physics, Washington University, St Louis, Missouri, USA
⁵ Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri, USA
⁶ McDonald Research Laboratories, St Paul’s Hospital, University of British Columbia, Vancouver, British Columbia, Canada

Correspondence to:
Dr Joel D Cooper
Hospital of the University of Pennsylvania, 3400 Spruce St, 6 Silverstein, Philadelphia, Pennsylvania 19104, USA; joel.cooper{at}uphs.upenn.edu

Background: The hypothesis that ventilation of emphysematous lungs would be enhanced by communication with the parenchyma through holes in the pleural surface was tested.

Methods: Fresh human lungs were obtained from patients with emphysema undergoing lung transplantation. Control human lungs were obtained from organ donors whose lungs, for technical reasons, were not considered suitable for implantation. Lungs were ventilated through the bronchial tree or transpleurally via a small hole communicating with the underlying parenchyma over which a flanged silicone tube had been cemented to the surface of the lung (spiracle). Measurements included flow-volume-time curves during passive deflation via each pathway; volume of trapped gas recovered from lungs via spiracles when no additional gas was obtainable passively from the airways; and magnetic resonance imaging assessment of spatial distribution of hyperpolarised helium (³He) administered through either the airways or spiracles.

Results: In emphysematous lungs, passively expelled volumes at 20 s were 94% greater through spiracles than via the airways. Following passive deflation from the airways, an average of 1.07 litres of trapped gas volume was recoverable via spiracles. Regions were ventilated by spiracles that were less well ventilated via bronchi.

Conclusions: Because of the extensive collateral ventilation present in emphysematous lungs, direct communication with the lung parenchyma through non-anatomical pathways has the potential to improve the mechanics of breathing and hence ventilation.

Abbreviations: CL, lung compliance; FEV₁, forced expiratory volume in 1 s; FVC, forced vital capacity; Gaw, airway conductance; Gsp, spiracle conductance; PA, alveolar pressure; Pel, elastic recoil pressure; Pfr, pressure producing flow; Ppl, pleural pressure; ROI, region of interest; RV, residual volume; TLC, total lung capacity; VC, vital capacity

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

• Coxson, H. O., Mayo, J., Lam, S., Santyr, G., Parraga, G., Sin, D. D. (2009). New and Current Clinical Imaging Techniques to Study Chronic Obstructive Pulmonary Disease. Am. J. Respir. Crit. Care Med. 180: 588-597 [Abstract] [Full Text]  
• Choong, C. K., Macklem, P. T., Pierce, J. A., Das, N., Lutey, B. A., Martinez, C. O., Cooper, J. D. (2008). Airway Bypass Improves the Mechanical Properties of Explanted Emphysematous Lungs. Am. J. Respir. Crit. Care Med. 178: 902-905 [Abstract] [Full Text]  
• Grgic, A., Wilkens, H., Kubale, R., Groschel, A., Buecker, A., Sybrecht, G. W. (2008). Low-Dose MDCT for Surveillance of Patients with Severe Homogeneous Emphysema After Bronchoscopic Airway Bypass. Am. J. Roentgenol. 191: W112-W119 [Abstract] [Full Text]