Nitric oxide may be involved in the impaired oxygenation of cirrhotic patients, a condition that improves in most patients after liver transplantation. To compare oxygenation and nitric oxide concentrations before and after liver transplantation. Before-and-after observational study. Academic medical center. 18 patients with cirrhosis and no obvious cardiopulmonary disease who underwent successful orthotopic liver transplantation. Orthotopic liver transplantation. Blood gas analysis, measurement of exhaled nitric oxide, contrast-enhanced echocardiography, and pulmonary function tests. Before transplantation, the mean (±SD) exhaled nitric oxide concentration was higher in patients than in normal controls (13 ± 4.9 parts per billion [ppb] compared with 5.75 ± 1.9 ppb; P < 0.001). After transplantation, the alveolar-arterial oxygen gradient significantly decreased (from 17.3 ± 7.1 mm Hg to 9 ± 5.2 mm Hg; P < 0.001), as did the exhaled nitric oxide concentration (from 13 ± 4.9 ppb to 6.2 ± 2.8 ppb; P < 0.001). The decrease in the exhaled nitric oxide concentration was significantly correlated with the decrease in the alveolar-arterial oxygen gradient (r = 0.56; P = 0.014). Five patients met the criteria for the diagnosis of the hepatopulmonary syndrome before transplantation; the syndrome was cured by transplantation. The correlation between the decrease in exhaled nitric oxide concentration after liver transplantation and the improvement in oxygenation reinforces the hypothesis that nitric oxide is an important mediator of impaired oxygenation in patients with cirrhosis.

The objective of this study was to examine the relation between respiratory function tests, disease activity and disease severity in ambulatory patients with systemic lupus erythematosus (SLE) who did not present with overt respiratory problems. Lung volumes, maximal expiratory flows at 50% and 25% of vital capacity (MEF₅₀ and MEF₂₅), bronchial threshold to methacholine (PD₁₅FEV ₁), transfer factor CO (KCO) were measured in 24 consecutive SLE outpatients (22 women, age 41 ± 14.8 years) and in 24 healthy controls matched for age and sex. In SLE patients alveolar-arterial oxygen gradient (AaO₂) was also measured. Disease activity was assessed by European Consensus Lupus Activity Measurement (ECLAM) scoring system and disease severity by Lupus Severity of Disease Index. In comparison to controls SLE patients showed a significant decrease of total lung capacity (TLC) (91.7 ± 16.5 vs 102.7 ± 12.9% predicted, P < 0.01), MEF₂₅ (58.4 ± 25.2 vs 73.5 ± 19.5% predicted, P < 0.005), PD₁₅FEV₁ (2164 ± 1122 vs 4230 ± 1014 μg methacholine, P < 0.0001) and KCO (77.1 ± 20.5 vs 96.3 ± 12.4% predicted, P < 0.001). AaO₂ (mean value 13.2 ± 8.4) was abnormally high (>20 mm Hg) in 12 patients. The ECLAM score of activity was inversely related with KCO (r = 0.48, P < 0.02). The severity index was significantly related with FEV₁/VC ratio (r = 0.43, P < 0.05), MEF₅₀ (r = 0.51, P < 0.01), MEF₂₅ (r = 0.40, P < 0.05) and PD₁₅FEV₁ (r = 0.51, P < 0.01). In eight patients, evaluated also after treatment intensification, there was a significant increase in KCO (from 71.8 ± 24.7 to 84.9 ± 22.3% predicted, P < 0.01) along with a decrease in ECLAM score (from 3.0 ± 1.34 to 0.69 ± 0.75, P < 0.01). The relation between disease activity and KCO suggests a relation between systemic and alveolar inflammation whereas the relation between severity index, airway patency and reactivity indices suggests a cumulative damage to the airways in SLE patients, even in the absence of overt respiratory manifestations.