The term ‘hepatopulmonary syndrome’ refers to a clinical correlation between impaired hepatic function and pulmonary blood vessel distension accompanied by abnormalities in arterial blood oxygenation. Hepatopulmonary
syndrome develops in patients with advanced liver diseases, most frequently cirrhosis or chronic active hepatitis. Patients with fully developed hepatopulmonary syndrome present respiratory symptoms such as cyanosis,
dyspnea, platypnea, orthodeoxia, clubbed fingers. Platypnea is dyspnea occurring due to assuming a sitting position, which subsides after lying down, while orthodeoxia is a decrease of oxygen pressure in capillary blood
associated with assuming a sitting position. Hepatopulmonary syndrome and consequent respiratory symptoms are due to vascular changes involving distension of precapillaries, presence of arteriovenous shunts within the lungs and so-called spider angiomas in the pleura. Precapillary and capillary distension leads to impairment of perfusion and diffusion mechanisms,
Consequently, the mixture of arterial and venous blood passes to the pulmonary veins, which leads to hypoxia. According to the predominating opinion, angiotensin II is an etiologic factor for this syndrome. The development
of hepatopulmonary syndrome symptoms, due to vascular distension, is believed to be associated with abnormal response to angiotensin II (reducet vasoconstricting effect) and with simultaneous inscrease of the concentration
of nitrogen oxide – a vasodilating factor. The diagnostic criteria include: 1) documented acute or chronic liver disease, 2) presence of pulmonary vascular distension and increased alveoloarterial gradient in the respiratory process. It has been emphasized that liver transplantation, is the only effective method of treatment, providing at the same time evidence for the reversibility of hepatopulmonary syndrome. The attempts of pharmacological treatment undertaken so far have yielded disappointing results. Further search for new methods of treatment effective in hepatopulmonary syndrome is necesary.

Keywords: hepatopulmonary syndrome, orthodeoxia, platypnea, pathogenesis, diagnostics, treatment