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Eur J Cardiothorac Surg 2006;30:202-203
© 2006 Elsevier Science NL

Letter to the Editor

Should carbon monoxide lung diffusion capacity (DLCO) measurement be mandatory before lung resection?

Division of Thoracic Surgery, Department of Surgical Oncology, Tata Memorial Hospital, Mumbai 400012, India

Received 29 March 2006; accepted 5 April 2006.

^_* Corresponding author. Tel.: +91 22 24177000; fax: +91 22 24146937. (Email: cspramesh{at}vsnl.net).

Key Words: Carbon monoxide lung diffusion capacity • DLCO • Risk stratification

We congratulate Brunelli and colleagues [1] on their recent paper reiterating the importance of diffusion capacity of carbon monoxide (DLCO) for perioperative risk stratification in lung resectional surgery. The theoretical basis for measurement of DLCO is the ability to evaluate gas exchange at the alveolar-capillary level as opposed to only measurement of lung volumes in conventional pulmonary ‘function’ tests (PFT). Gas exchange is based on simple diffusion and is therefore dependent on the surface area available, a short diffusion path between alveolar air and the capillaries and the concentration gradients for oxygen and carbon dioxide between the alveolar air and blood. None of these variables is dependent on lung volumes and mere measurement of lung volumes will not accurately assess the ‘functionality’ of the lung. Especially in pathologies like interstitial lung disease (ILD), lung volumes are frequently normal or even supranormal but gas exchange and consequently DLCO measurements show extremely low values. Moreover, there cannot be (even theoretically) reasonable correlation between lung volumes as measured by vital capacity and FEV1 and gas exchange as measured by DLCO. Therefore, it seems illogical to restrict measurement of DLCO only in patients whose forced expiratory volume in 1 s (FEV1) is less than 80%. This is clearly demonstrated by Brunelli's study which shows at best, average correlation between the two. The importance of DLCO is also illustrated by the finding that postoperative complications were twice as frequent and mortality almost thrice as frequent in patients with low predicted postoperative DLCO (ppoDLCO). We do a fair number of lung resections in our hospital (primarily for lung cancer) and consider ppoFEV1 and ppoDLCO values of 40% and a ppoFEV1 (%) x ppoDLCO (%) product of 1500 as a cut-off for considering lung resection. It is surprising that even after numerous previous studies on the topic [2–4], DLCO measurement prior to surgery is not universally done. We strongly urge the adoption of routine DLCO testing in patients undergoing lung resectional surgery regardless of conventional PFT results.

References

1. Brunelli A, Refai MA, Salati M, Sabbatini A, Morgan-Hughes NJ, Rocco G. Carbon monoxide lung diffusion capacity improves risk stratification in patients without airflow limitation: evidence for systematic measurement before lung resection. Eur J Cardiothorac Surg 2006;29:567-570.[Abstract/Free Full Text]
2. Wang J, Olak J, Ferguson MK. Diffusing capacity predicts operative mortality but not long-term survival after resection for lung cancer. J Thorac Cardiovasc Surg 1999;117:581-587.[Abstract/Free Full Text]
3. Pierce RJ, Copland JM, Sharpe K, Barter CE. Preoperative risk evaluation for lung cancer resection: predicted postoperative product as a predictor of surgical mortality. Am J Respir Crit Care Med 1994;150:947-955.[Abstract]
4. Ferguson MK, Little L, Rizzo L, Popovich KJ, Glonek GF, Leff A, Manjoney D, Little AG. Diffusing capacity predicts morbidity and mortality after pulmonary resection. J Thorac Cardiovasc Surg 1988;96:894-900.[Abstract]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Rajesh C. Mistry Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Pramesh, C.S. Articles by Mistry, R. C. Search for Related Content PubMed PubMed Citation Articles by Pramesh, C.S. Articles by Mistry, R. C. Related Collections Lung - other