Patients with advanced liver disease, due to the mechanisms and pathophysiologic changes seen in liver failure, are at increased risk of pulmonary comorbidities (Table 36-1). Along with a thorough general preoperative evaluation, these patients should undergo a complete pulmonary evaluation to determine if any condition should be addressed prior to liver transplantation to prevent complications in the perioperative and postoperative periods (Fig. 36-1). In addition to general preoperative issues, pulmonary complications of end-stage liver disease include elevation of the diaphragm, atelectasis, and pleural effusions, which are attributed to hepatosplenomegaly, ascites, and hypoalbuminemia, respectively.1 Other less common complications include hepatopulmonary syndrome2 and pulmonary hypertension associated with portal hypertension (portopulmonary hypertension [PPHTN]).3 It is important to identify these patients and make sure that they are treated aggressively, as postoperative pulmonary complications in nonthoracic surgery patients have been reported in 2% to 19% of patients.4 This chapter attempts to outline the preoperative pulmonary assessment of liver transplant patients.
Management protocol for pulmonary evaluation in liver transplant patients.
TABLE 36-1General and Pulmonary Preoperative Risk Factors ||Download (.pdf) TABLE 36-1 General and Pulmonary Preoperative Risk Factors
General Preoperative Risk Factors
Pulmonary Preoperative Risk Factors in Liver Disease
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Abnormal pulmonary function test
Hepatopulmonary syndrome (HPS)
Portopulmonary hypertension (PPHTN)
AGE AND NUTRITIONAL STATUS
In all surgical candidates, the general examination should include age and nutritional status. It is well known that age is a risk factor for surgical complications, and advancing age is associated with increasing frequency of complications of abdominal surgeries.5 In addition, nutritional status should be assessed and optimized, as 44% of the patients are malnourished on admission for intrabdominal surgery. Malnutrition in itself is considered a marker for poor surgical outcomes.6
Obesity is defined as a body mass index (BMI) greater than or equal to 30 kg/m2 and has been recognized by the American Medical Association as a disease state that is a risk factor for all surgical patients. Excess abdominal fat (central or visceral obesity), which is found above the waist, is related to increased risk of diabetes, heart disease, postoperative pulmonary complications. A waist circumference greater than 40 inches in men or 36 inches in women is of concern. From a pulmonary point of view, obesity leads to decreased lung volumes after surgery and is a principal cause of postoperative pulmonary complications. Morbid obesity causes a restrictive ventilatory pattern and decreases thoracic compliance and may lead to alveolar hypoventilation.7...