Mer,
hepatopulmanary syndrome is the dilitation of pulmanary arteries in the cappulary stage. 2 methods can test for it. An echocardiogram with contrast which will show right to left blood shunting. And a nuculear medicine perfusion lung scan with Tc99 MAA....on the lung scan increased activity will show in the brain.......
Tell your pulmonologist this he might think you know whats going on........If he does have yhis he gets moved up..........15 to 20 percent of ESLD pts have this.........many die undiagnosed..........If the pt doesent have underlying heart disease, or lung disease they prob have hps...........Its worth the 2 tests. There are specialized pulmanary function tests also that can be done. but the 2 I gave ya are the gold standard for diagnoses