Am J Respir Crit Care Med 201 (11): 1575 - 1578, 2020. doi: 10.1164 / rccm.201912 - 2514LE Diagnosis of Hepatopulmonary Syndrome Pulse oximetry Contrast echocardiography and sometimes other imaging Hepatopulmonary syndrome should be suspected in patients with known liver disease who report dyspnea (particularly platypnea).