Hypoxemia In Liver Cirrhosis And Intrapulmonary Shunt Determination Using Tc-99m-MAA Whole Body Scan

Lee, Kye Young; Kim, Young Whan; Han, Sung Koo; Shim, Young Soo; Kim, Keun Youl; Han, Yong Chol

Abstract

BACKGROUND
It is well known that severe hypoxemia is often associated with liver cirrhosis without preexisting cardiac or pulmonary diseases. Pulmonary vascular impairments, more specifically, intrapulmonary shunting have been considered as a major mechanism. Intrapulmonary shunting arises from pulmonary vascular dilatation at the precapillary level or direct arteriovenous communication and has relationship with the characteristic skin findings of spider angioma. However, these results are mainly from Western countries where alcoholic and primary biliary cirrhosis are dominant causes of cirrhosis. It is uncertain that tie same is true in viral hepatitiss associated liver cirrhosis, which is dominant causes of liver cirrhosis in Korea. We investigated the incidences of hypoxemia and orthodeoxia in Korean cirrhotic patients dominantly composed of postnecrotic cirrhosis and the significance of intrapulmonary shunting as the suggested mechanism of hypoxemia. METHOD: We performed the arterial blood gas analysis separately both at the supine and errect position in 48 stable cirrhotic patients without the evidences of severe complications such as ascites, variceal bleeding, and hepatic coma. According to the results of arterial blood gas analysis, all patients were divided into hypoxemic and normoxemic group. In each group, pulmonary function test and Tc-99m-MAA whole body scan were performed. The shunting fraction was calculated based on the fact that the sum of cerebral and bilateral renal blood flow is 32% of the systemic blood flow.
RESULTS
The hypoxemia of PaO2 less than 80 mmHg was observed in 9 patients(18.8%) and Orthodeoxia more than 10 mmHg was observed in 8 patients(16.7%). Hut there was no patient with significant hypoxemia of PaO2 less than 60 mmHg. PaO2 was significantly decreased in the patients with spider angioma than the patients without spider angioma and showed no correlation with the serologic type and severities of liver function test findings. Any parameters of pulmonary function test did not demonstrate the difference between normoxemic and hypoxemic group. But hypoxemic group showed significantly increased shunt fraction of 11.4+/-4.1% than normoxemic group of 4.1+/-2.0% (p<0.05).
CONCLUSIONS
Hypoxemia is not infrequently observed complication in liver cirrhosis and intrapulmonary shunting is suggested to play a major role in the development of hypxemia. But there was no great likelihood of clinically significant hypoxemia in our domestic cirrhotic patients predominantly composed of postnecrotic type.