Acute Respiratory Failure and Pulmonary Complications in End-Stage Liver Disease

Nida Qadir, MD; Tisha Wang, MD; Igor Barjaktarevic, MD, PhD; Steven Y. Chang, MD, PhD

Disclosures

Semin Respir Crit Care Med. 2018;39(5):546-555. 

In This Article

Hepatic Hydrothorax

Hepatic hydrothorax is a frequent complication of ESLD and represents the accumulation of fluid in the pleural cavity in the absence of direct cardiac or pulmonary etiologies. This phenomenon is seen in 5 to 12%[10] of patients with advanced liver disease and, while commonly seen in the presence of ascites, can also be seen in its absence. HH is most often found in the right pleural cavity (73–87%),[10] but patients may present with bilateral (2–10%) or isolated left sided (13–17%) effusions as well.[34,35] Pathophysiologically, decreased oncotic pressure, increased azygos system pressure, and portal hypertension drive the accumulation of fluid in extravascular spaces and body cavities. The most important mechanism for development of a large pleural effusion is likely the increased pressure in the portal venous system, which allows fluid to leak out from the interstitial spaces into the peritoneal cavity, producing ascites. This fluid, originating in the peritoneal space, moves into the pleural cavity via subtle diaphragmatic defects. Studies using intraperitoneal administration of radiolabeled tracer demonstrate this shift of fluid into the negative-pressure intrapleural space.[10,36–41] As this is unidirectional flow, it is not surprising that HH may occur even in the absence of a significant amount of ascites.[35]

The clinical significance of HH varies considerably. Small- or moderate-sized effusions may not have a significant impact on activities of daily living, although some degrees of dyspnea, nonproductive cough, or exertional pleuritic chest pain are usually present. Large, especially bilateral, effusions can lead to chronic hypoxemic or hypercapnic respiratory failure. In the setting of advanced liver disease and hypervolemia, worsening hydrothorax is usually accompanied by pulmonary edema, which together can lead to the need for mechanical ventilation. Management of symptomatic HH consists of salt restriction and volume optimization with diuretics. Thoracentesis is indicated if the diagnosis is unclear, but large volume thoracenteses and especially chest tubes should generally be avoided unless the HH is persistent and severe in spite of adequate diuresis, as these measures can lead to fluid depletion and protein loss, and come with increased risk of bleeding due to the coagulopathies frequently present in ESLD.[42,43] In cases that are refractory and severe, transjugular intrahepatic portosystemic shunt or indwelling pleural catheter placement may be considered. Liver transplant is the only definitive treatment for HH.[44]

Pleural effusions associated with portal hypertension are generally transudative.[45] Nevertheless, multiple confounding factors which may affect the composition of pleural fluid exist, including diuretics, previous thoracenteses, or intra-abdominal processes, making pleural fluid analysis more difficult. In general, the interpreting physician should be able to use data obtained by thoracentesis to assess for the presence of infection and whether the presence of the fluid will have a significant clinical impact on the patient's course.

A long-lasting HH can lead to a myriad of complications which may impact the overall prognosis of an ESLD patient. One such complication is spontaneous bacterial empyema (SBEM), which is similar to spontaneous bacterial peritonitis in patients with ascites, and may develop in 13 to 16% of cirrhotic patients with HH.[46] Diagnosis of SBEM is made by pleural fluid analysis, which will show a polymorphonuclear neutrophil (PMN) count >250 cells/mm3 along with positive pleural fluid cultures, or a PMN count > 500 cells/mm3 without positive cultures. SBEM should only be diagnosed in the absence of pneumonia.[47] Appropriate antibiotics are the mainstay of treatment. Chest tube drainage should only be pursued in the event that a true empyema develops. SBEM is associated with a mortality rate of up to 38%.[48,49]

A large HH may lead to atelectasis and even lobar collapse, especially in deconditioned and immobile patients, which may cause dyspnea and hypoxia. Acute tension hydrothorax[50] is a rarely seen complication probably related to the presence of pleuroperitoneal bleb[51,52] or larger diaphragmatic defects allowing for rapid fluid accumulation in the pleural space. Persistent atelectasis, especially in the setting of inflammatory, infectious, or sanguinous effusions may lead to a fibrous visceral pleural thickening that prevents lung re-expansion, thus leading to chronic atelectasis and trapped lung. Thoracentesis and removal of fluid may lead to a hydropneumothorax or pneumothorax ex vacuo (Figure 2). Definitive management consists of decortication, but the surgical risk may be prohibitive in patients with advanced liver disease. While trapped lung rarely leads to respiratory failure itself, it may cause significant symptoms in an already debilitated ESLD patient. In individuals who are on invasive mechanical ventilation (IMV), weaning from the ventilator may prove to be particularly challenging, and should be taken into consideration when evaluating patients for transplant (Figs. 1 and 2).

Figure 1.

Hepatic hydrothorax.

Figure 2.

Trapped lung with postthoracentesis pneumothorax ex vacuo.

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....