Intrapulmonary Shunt in the Course of Pediatric Liver Transplantation

Abstract

The hepatopulmonary syndrome occurs when an intrapulmonary shunt (IPS) causes hypoxemia in patients with cirrhosis. Because IPS has not been clearly defined in children, we investigated the prevalence, clinical characteristics, and outcomes of IPS in children undergoing liver transplantation (OLT). Of the 107 pediatric OLT recipients between December 1994 and March 2005, 18 (16.8%) had IPS, as evaluated by contrast-enhanced echocardiography (CEE) at 9 months to 16 years of age. The degree of IPS was classified into five grades according to the extent of microbubbles in the left ventricle, with significant IPS defined as grade II or higher. Baseline characteristics, including serum total bilirubin, albumin, aminotransferase, and prothrombin time, did not differ in patients with or without IPS. The patients with IPS had significantly lower Pa o 2 and Sa o 2, longer duration of mechanical ventilation and hospital stay, and higher postoperative morbidity and mortality than patients without IPS ( P < .05 each), but there were no other significant differences between the groups. The six patients with significant IPS (one grade II, three grade III, and two grade IV) showed a significantly greater morbidity and mortality than patients with grade I IPS ( P < .05). Most of the positive CEE findings of IPS regressed within 6 months after OLT. These findings indicated that IPS is not uncommon among children undergoing OLT, but is reversible. Because severe IPS may increase patient morbidity and mortality, early assessment of IPS status using CEE is essential for pediatric OLT candidates.