Patients with advanced chronic liver disease can develop specific pulmonary complications related or unrelated to pre-existing lung disease. The three major pulmonary complications in this patient population include hepatopulmonary syndrome (HPS), portopulmonary hypertension (PoPH), and hepatic hydrothorax (HH). These entities are most often revealed by increasing dyspnea together with signs of portal hypertension. The prevalence of these complications remains underestimated due to the lack of routine screening of the cirrhotic population. The pathophysiology of HH is better understood than that of HPS and PoPH. The clinical features, diagnosis, and therapeutic options of these pulmonary complications are extensively discussed in this chapter. Liver transplantation may offer a curative therapy in highly-selected cases and MELD exception points allow priority access to liver transplantation, thus avoiding potential deterioration while awaiting transplant and providing a better post liver transplant survival. The complexity of managing these pulmonary complications requires a multidisciplinary team approach, especially when liver transplantation is indicated.

Acute decompensation is defined as the development of ascites, bleeding due to portal hypertension, jaundice, or hepatic encephalopathy in the presence of known or unknown chronic liver disease. Acute-on-chronic liver disease is defined as a clinical entity reflecting acute worsening in liver function along with extrahepatic organ failure with significantly higher 28-day mortality. In the common pathogenesis, severe systemic inflammation and portal hypertension and varying degrees of reaction to these conditions play a major role. Triggering factors act as accelerators in the development of acute decompensation and acute-on-chronic liver failure. The extrahepatic organ failure in acute-on-chronic liver failure is mainly due to tissue hypoxia due to decreased perfusion and cellular edema. The number of organ failure in acute-on-chronic liver failure is considered to be the most important prognostic indicator. Liver transplantation remains the most appropriate treatment option for selected patients, even though supportive therapies based on the severity of the disease and the clinical findings that have developed are at the forefront.

With the rising prevalence of chronic liver disease worldwide, the incidence and prevalence of acute-on-chronic liver failure (ACLF) are increasing and attribute to higher morbidity, mortality, and healthcare costs. Many of such patients die without being considered for the lifesaving treatment option of liver transplantation. The underutilization of liver transplantation as a therapeutic option in the setting of ACLF, is due to multiple reasons; with the heterogeneity of ACLF and the lack of universal definition being the key players. Liver transplantation listing and allocation are based on MELD score. As of now, we do not know where MELD score stands in regard to defining ACLF and the prognostication of such patients. This insight is very important for the efficient identification of potential liver transplantation candidates in the setting of ACLF. This review paper investigates the role of liver transplantation in the setting of ACLF. In light of recent evidence, MELD score is not the perfect model in the setting of ACLF either. The safety of liver transplantation, either deceased donor or living donor, among ACLF patients has been debated. The short-term mortality rate of ACLF patients has created a need for a standard liver transplant selection criterion for these patients. Based on published literature, we find that three commonly used ACLF definitions may be used in combination to define the sensitivity, specificity, and futility of ACLF and we propose an algorithm to best identify patients for urgent liver transplantation in the setting of ACLF. Moreover, we discuss the data on the safety of liver transplantation in the setting of ACLF. Future validation of this multifaceted approach could bridge the gap between ACLF patients and appropriately guided medical intervention.

Transabdominal ultrasound is a valuable diagnostic approach for evaluating the gastrointestinal tract and related disorders. This dynamic examination provides real-time visualization of the digestive tube and surrounding structures, assessment of peristaltic movements, estimation of compressibility of intestinal loops, and recognition of painful spots requiring specific attention. Since ultrasound imaging is non-invasive, painless, reproducible, inexpensive and requires no special preparation, it is used as a major diagnostic tool in emergency settings and in outpatient follow-up of several disorders. Costs, encompassing both accessibility and actual procedural expenses, are lower than those associated with other diagnostic techniques. However, the incorporation of gastro-intestinal ultrasound (GIUS) in clinical practice has not been widely used on a global scale. The purpose of this paper is to provide an overview of the execution techniques as well as the main areas of application for GIUS. Through illustrative iconographic representation, emphasis was placed on its potential within the diagnostic and therapeutic pathway of various acute and chronic gastrointestinal disorders.