Submitted on December 19, 2008
Revised on April 20, 2009
Accepted on May 7, 2009
Nitric oxide and carbon monoxide lung transfer in patients with advanced liver cirrhosis
Bruno Degano1*, Marie Mittaine2, Herve Guenard3, Jacques Rami2, Gilles Garcia4, Nassim kamar5, Christophe Bureau6, Jean-Marie Peron6, Lionel Rostaing5, and Daniel Riviere7
1 CHU Antoine Béclère
2 CHU Larrey
3 University Victor Segalen Bordeaux II
4 Hôpital Antoine Béclère
5 Dialyse et Transplantation d'Organes
6 CHU Purpan
7 Service d'Exploration de la Fonction Respiratoire et de Médecine du Sport Clinique des Voies Respiratoires - Hôpital LARREY 24, chemin de Pouvourville TSA 30030 - 31059 TOULOUSE
* To whom correspondence should be addressed. E-mail: degano.b{at}gmail.com.
Background: In advanced cirrhosis, decreased lung transfer for carbon monoxide (TLCO) and increased alveolar-arterial oxygen tension difference (PA-aO2 
15 mmHg while breathing ambient air) are frequently detected. Pulmonary membrane diffusion capacity for CO (DmCO) and pulmonary capillary blood volume (Vcap) can be derived from the simultaneous measurement of TLCO and lung transfer for nitric oxide (TLNO). Methods: Measurements of single breath TLNO and TLCO were performed in 49 cirrhotic patients with advanced liver cirrhosis and in 35 healthy controls to derive Vcap, DmCO and TLNO:TLCO ratio. Results: 25 patients had increased PA-aO2, of whom 11 had hepatopulmonary syndrome (HPS). Compared with controls, non-HPS patients with normal PA-aO2 had a significant ~10% decrease in TLCO, DmCO and Vcap, but similar TLNO:TLCO ratios. Compared with non-HPS patients with normal PA-aO2, non-HPS patients with increased PA-aO2 had lower Vcap and higher TLNO:TLCO ratio, but similar DmCO. HPS patients had lower Vcap and higher TLNO:TLCO ratios than both subgroups of non-HPS patients. In cirrhotic patients, TLNO:TLCO ratios correlated positively and TLCO (%pred) and Vcap (%pred) correlated negatively with PA-aO2 (r2=0.25, p=0.0003, r2=0.48, p<0.0001 and r2=0.57, p<0.0001, respectively). Conclusion: In cirrhotic patients, lower TLCO and increased PA-aO2 are associated with lower Vcap. In addition, high TLNO:TLCO ratios in patients with increased PA-aO2 suggest a decreased thickness of the capillary blood layer in these patients.
