The propofol infusion syndrome: more puzzling evidence on a complex and poorly characterized disorder.

The propofol infusion syndrome is a potentially devastating cardiovascular and metabolic derangement that has been described in both pediatric and adult patients sedated with propofol. Despite a large number of case reports that have appeared in the literature since 1992, the precise clinical features and pathophysiology of this disorder remain uncertain. Historically, the syndrome has been characterized by the occurrence of lactic acidosis, rhabdomyolysis, and circulatory collapse after several days of high-dose propofol infusion. The affected patients were typically young and critically ill, and the reported mortality was high. More recently, a number of atypical cases have been reported with favorable outcomes. These occurred after short-term or lower-dose infusions in noncritically ill patients in whom generally only a subset of the classical syndrome features was observed. It remains unclear whether these reports reflect true propofol infusion syndrome detected at an earlier and more salvageable stage, or mere associations with the use of sedative agents in general. Without better information on the true incidence of the propofol infusion syndrome, clinical guidelines on the safe use of this drug remain unsupported by good evidence.