[Hepato-pulmonary syndrome: meta-analysis]

Abstract

Introduction and objectives: The clinical introduction of multiple elimination of inert gases (MEIG) has meant a qualitative advance in our understanding of the physiopathology of a wide range of pulmonary diseases. This meta-analysis aims to bring together data on patients with cirrhosis of the liver from 3 similar studies in which MEIG was used.

Patients and methods: The results from 30 patients in 3 studies, divided into 2 groups based on baseline partial arterial O2 pressure (hypoxemic: PaO2 < 80 mmHg, n = 17; normal: PaO2 > or = 80 mmHg, n = 13) were subjected to statistical analysis.

Results: The hypoxemic group experienced an increase in the percentage of cardiac output perfusing regions of shunting (10.1 +/- 10 vs. 1.08 +/- 1.6%; p < 0.01) and low ventilation/perfusion relationships (16.3 +/- 10.3 vs. 3.5 +/- 5.8%; p < 0.01). We also observed greater dispersion in the distribution of perfusion (1.09 +/- 0.43 vs. 0.67 +/- 0.34; p < 0.01) and ventilation (0.62 +/- 0.14 vs. 0.49 +/- 0.13; p < 0.05), with the ventilation mean located in regions with higher ventilation/perfusion relationships (1.3 +/- 0.5 vs. 0.85 +/- 0.15; p < 0.01). The difference between observed and calculated PaO2 was significant in the hypoxemic group (7.3 +/- 5.5 vs. 1.2 +/- 1.3 mmHg; p < 0.01).

Conclusions: Hypoxemia in patients with cirrhosis of the liver is mainly due to changes in ventilation/perfusion relationships and shunting. In the most hypoxemic patients, however, we cannot rule out a role for the causes of hypoxemia, such as diffusion changes.