Bilirubin in the early course of venovenous extracorporeal membrane oxygenation support for refractory ARDS

Bilirubin is known as a marker of hepatic dysfunction and is incorporated in scoring algorithms to assess prognosis in critically ill patients. No data are so far available on the prognostic role of hepatic dysfunction in patients with severe ARDS on venovenous extracorporeal membrane oxygenation (VV-ECMO) support. In 112 consecutive patients with severe ARDS treated with VV-ECMO, we aimed at assessing whether increased bilirubin during the first 72 h could affect early death. Increased serum bilirubin (≥1.2 mg/dl) was detectable in 29 patients (25.9%) who were older (p = 0.031), exhibited a higher SOFA score (p = 0.006), were more frequently given pre-ECMO muscular blockers (p = 0.001) and supported with ECMO for a longer period (p = 0.024), when compared to patients with normal bilirubin. No difference in in-ICU mortality rate was observed between the two subgroups. In survivors, bilirubin showed a progressive and significant decrease (p = 0.032) during the first 72 h of ECMO support, while it increased in dead patients (p = 0.007).The mortality rate was higher in patients with increased bilirubin at 24, 48 and 72 h after ECMO start in respect to that of patients with normal values. Pre-ECMO increased bilirubin values (≥1.2 mg/dl), being detectable in about one-fourth of the entire population, is not associated with increased in-ICU mortality, while the persistence of increased bilirubin values after 24 h of ECMO start and within the first 3 days identified a subgroup of patients at higher risk of death.