Pulmonary Issues in Chronic Liver Disease

Abstract

Pulmonary complications are important cause for high incidence of mortality in chronic liver disease patients admitted to the intensive care unit. Up to 50–70% of patients report shortness of breath, reflecting the high prevalence of respiratory failure, defined as an arterial pressure of oxygen (PaO2) of less than 60 mm Hg. The causes of respiratory failure are multifactorial in chronic liver disease. Although much attention is given to the pathologies of pulmonary microcirculation (i.e., portopulmonary hypertension and hepatopulmonary syndrome), these specific conditions are found in <20% of cirrhotic patients. The impact of liver disease on respiratory function extends far beyond these two specific conditions and include micro-aspirations associated with hepatic encephalopathy, fluid overload, hepatic hydrothorax, and basal atelectasis and restriction due to large ascites. The impact of altered bile-acid composition induces a shift in the gut microbiome and this may shed a new light on the molecular basis for the ‘gut–liver–lung axis’ as the driver for multiple organ failure. This chapter focuses on current evidence surrounding the prevalence, management, and complications from various etiologies of respiratory insufficiency in end-stage liver disease patients.